Psychological effects of polar expeditions

Review

Psychological effects of polar expeditions Lawrence A Palinkas, Peter Suedfeld

Polar expeditions include treks and stays at summer camps or year-round research stations. People on such expeditions generally undergo psychological changes resulting from exposure to long periods of isolation and confinement, and the extreme physical environment. Symptoms include disturbed sleep, impaired cognitive ability, negative affect, and interpersonal tension and conflict. Seasonal occurrence of these symptoms suggests the existence of three overlapping syndromes: the winter-over syndrome, the polar T3 syndrome, and subsyndromal seasonal affective disorder. About 5% of people on expeditions meet DSM-IV or ICD criteria for psychiatric disorders. However, they also experience positive or so-called salutogenic outcomes resulting from successfully coping with stress and enhanced self-sufficiency, improved health, and personal growth. Prevention of pathogenic psychological outcomes is best accomplished by psychological and psychiatric screening procedures to select out unsuitable candidates, and by providing access to psychological support, including telephone counselling. Promotion of salutogenic experiences is best accomplished by screening for suitable personality traits, and training participants in individual coping strategies, group interaction, and team leadership. The history of polar exploration consists of many tales of heroism, bravery, self-sacrifice, and conquest. It also has many tales of hardship, suffering, illness, and death. Although polar explorations were historically an activity for the purposes of economic gain, national pride, scientific discovery, or individual fame and recognition, they have now become much safer and more commonplace than before. Cruise ships laden with tourists are regular visitors to the Antarctic peninsula, Spitzbergen (Norway), and Greenland. Exploration for oil and subsequent development has contributed to an increase in the non-native population of the Arctic regions. Studies of global warming suggest that a year-round ice-free route across the Arctic ocean could become a reality in the near future, which could possibly lead to increased numbers of people travelling these waters for commercial, scientific, and recreational purposes.1 Nevertheless, apart from anecdotal reports of polar madness and cabin fever, little is known about the psychological demands people on polar expeditions face from the harsh physical and social environment. An understanding of these demands is of great importance for prevention and treatment of morbidity and mortality related to poor psychosocial and neurobehavioural adaptation to this extreme and unusual environment. Polar expeditions also serve as a useful analogue to the psychological demands likely to be faced by people on long-duration space voyages.2–4

The heroic age Other than the exploration and settlement of Greenland by the Vikings in the 9th century, the first recorded polar expeditions were the three voyages of Martin Frobisher who sought the Northwest Passage in 1576–78. However, the heroic age of polar exploration really began with voyages to the Arctic and Antarctic in the early 19th century. Accounts of expeditions throughout the 19th and early 20th centuries rarely mentioned episodes of psychiatric disturbance or interpersonal conflict, as such was not in keeping with the image of polar explorers, who were www.thelancet.com Vol 371 January 12, 2008

expected to have specific qualities and characteristics, such as strength and resilience.5 Nevertheless, equally rare was the polar expedition that did not have at least one member who was debilitated by depression, anxiety, paranoia, alcoholism, or sleep disorders. During Sir Douglas Mawson’s second Antarctic expedition (1910–14), that person was Sydney Jeffryes, the radio operator, whom Mawson believed “surely must be going off his base. During the day he sleeps badly, gets up for dinner looking bad, husky; mutters sitting on his bunk in the dark afterward.”6 Frequently, the entire crew of a polar expedition would experience melancholy and depression, as was the case of the Belgica expedition to Antarctica in 1898–99. As described by the great polar explorer and expedition physician, Frederick A Cook, “The curtain of blackness which has fallen over the outer world of icy desolation

Lancet 2008; 371: 153–63 Published Online July 25, 2007 DOI:10.1016/S01406736(07)61056-3 School of Social Work, University of Southern California, Los Angeles, CA 90089, USA (Prof A Palinkas PhD); and Department of Psychology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada (Prof P Suedfeld PhD) Correspondence to: Lawrence A Palinkas, School of Social Work, University of Southern California, Los Angeles, CA 90089, USA [email protected]

Search strategy and selection criteria We searched for references listed in PsycINFO and PubMed (January 1975–November 2005), with the search terms “polar regions”, “polar expeditions”, ”Arctic”, “Antarctic”, in combination with the terms “behavior”, “performance”, and “mental health”. We also searched reference lists of articles identified by this search and selected those describing original research that included a specific focus on psychological or social dimensions of behaviour, performance, stress, and coping. The quality of the research described in these articles varied, from well-designed observational studies and randomised controlled trials of large groups of residents of polar research stations obtained over several years, to retrospective study of a single polar trek of two or three individuals using data collection techniques with poor reliability and validity. In each instance, the strengths and weaknesses of the research methodology was factored into our assessment of the usefulness of information derived from the study. Several review articles, book chapters, and earlier key publications known to us were also included.

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Present day polar expeditions

PA Photos

The printed journal includes an image merely for illustration

Expeditions to polar regions are challenging, both physically and psychologically

has descended upon the inner world of our souls. Around the tables, in the laboratory, and in the forecastle, men are sitting about sad and dejected, lost in dreams of melancholy from which, now and then, one arouses with an empty attempt at enthusiasm.”7 Cook tried to treat these symptoms by having crew members sit in front of large blazing fires. This baking treatment, as he called it, could be the first recorded attempt to use light therapy to treat symptoms of winter depression or seasonal affective disorder.8 Other expeditions, such as the Greely expedition of 1881–84, met a far worse fate than the Belgica exploration. In their attempt to establish a scientific base on Ellsmere Island in the Arctic, the crew of the Greely expedition was driven to mutiny, madness, suicide, and cannibalism, leaving six survivors of a crew of 25 men.9 No systematic attempt was made to understand and prevent these behaviours until the late 1950’s. These efforts were precipitated in Antarctica by a case of schizoaffective disorder at one station,10 and widespread interpersonal conflict precipitated by poor leadership at another11 during the International Geophysical Year (1957–58). These studies assessed the risk of psychological disturbances in people undertaking polar expeditions, and tried to identify interventions for their prevention, accounting for the logistical difficulty of treatment or evacuation of people who exhibit such disturbances. Gunderson,12 for instance, documented a three times increased risk of psychiatric disorders in US Navy personnel in Antarctica. Early studies by investigators such as Rivolier,3 Law,13 Mullin,14 Nardini and colleagues,10 and Palmai15 identified several risk factors rooted in sociodemographic characteristics such as age, education, and occupational status, and in personality traits such as extraversion and neuroticism. Subsequent investigations by Taylor16 and Natani and Shurley17 focused on the interpersonal dimension of psychological disturbances. 154

Three main types of polar expeditions take place today, and they entail a range of exposures to cold, danger, deprivation, and physical demands. The first type is the modern-day equivalent of the polar trek of the heroic era. Usually done in spring or summer months when weather conditions are most favourable, these expeditions are intended to recreate the experiences of the early polar explorers, or set new records for speed and distance. Other reasons for treks include drawing attention to the plight of Native peoples separated by the Cold War, such as the Bering Bridge Expedition in 1989, or to the effects of global warming on Native populations and polar bears, and transport of supplies and equipment to remote locations. Although some expeditions use traditional modes of travel (eg, sled dogs, skis, snowshoes), others use modern methods of transport (eg, snowmobiles, tractors, tracked vehicles). Ocean voyages in small sailing craft are also included in this category. Polar treks are usually the most challenging type of polar expedition because the team size is small, they entail the greatest exposure to the elements, the least access to the comforts of civilisation, and the highest physical demands. The second type of expedition is the summer camp. Such camps are usually for scientific (eg, glaciology, geology, marine biology) or commercial (eg, mineral or oil exploration) purposes. Camps range in size from three to 300 individuals who reside in tents, Quonset huts, or other temporary shelters. This category includes ocean voyages in large scientific research or commercial exploration vessels. The duration of such expeditions ranges from 2 weeks to 3 months. The third type of expedition is a period at a polar research station. In Antarctica, for example, 20 nations operate 47 permanent stations for the entire year. The population of these stations in the summer months (October–February) ranges from 14 to 1100 men and women, and from 10 to 250 during the winter months (March–September). Most of these residents are aged between 18 and 60 years. In the Arctic, comparable stations exist and are operated by the nations that border the circumpolar north (USA, Canada, Russia, Iceland, Sweden, and Norway). People on these expeditions are usually researchers in disciplines such as marine biology, astronomy, upper-atmosphere physics, meteorology, seismology, geology, and glaciology. Most of their time is spent indoors, especially in winter, and they usually have all the conveniences of modern life, including warm shelter, good food, communications with the outside world, and opportunities for leisure activity.

Expedition stressors Irrespective of the type of expedition, people face many stressors from the physical and psychosocial environment of high latitudes. These stressors were aptly summarised in Mear and Swan’s18 account of the Footsteps of Scott expedition in the Antarctic: “With each day that passed our www.thelancet.com Vol 371 January 12, 2008

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isolation increased and the fatigue grew. There was minimal time for sleep in the cramped tent. There was also a gnawing hunger and doubts that perhaps what we were attempting was impossible. No one had ever made such a journey without support, and if things were hard now, soon they would be harder, and all this added to the stress.” Participants of polar treks and traverses and, to a smaller extent, polar camps, must contend with periods of great physical exertion, fatigue, and exhaustion.19 Polar environments are filled with hazards such as crevasses, blizzards, slippery ice, frozen lakes, and open leads (ie, a channel of water through a field or flow of ice), which increase the likelihood of accidental injury and death.20,21 Cold temperatures are characteristic of polar environments, especially for people on treks or those who spend a substantial amount of time outdoors. Cycles of daylight and darkness become longer with increasing latitude, culminating in 6 months of light, or 6 months of dark at the poles. The polar regions are also characterised by low humidity and, depending on location, high altitude (eg, south pole). Physiological responses to these environmental conditions include light-related changes in circadian rhythms;22,23 altitude-related cardiopulmonary symptoms;24 and cold-related changes in peripheral circulation,25,26 hypothermia and frostbite,27–29 suppression of the immune system,30,31 and hormonal changes.29,32,33 The psychosocial environment of polar expeditions is characterised by isolation and confinement. Depending on the location and time of year, expeditions are usually physically isolated from the outside world, with darkness and weather conditions exerting severe restrictions on travel. People on such expeditions are separated from their family and friends and consequently feel degrees of emotional deprivation. Personal crises such as the death of a family member, financial difficulties, or deterioration of marital relations become magnified by the separation. At the same time, people experience social confinement within the expedition itself. Absence of privacy and constant gossip are frequent on polar expeditions and have a negative effect on social relations, especially relations between men and women.34 Little separation between work and leisure can exist because living and working spaces are close to one another, and each person interacts with the same group of individuals in both sets of activities. This constant interaction can also create increased social conflict between workers and supervisors, co-workers, cliques, or people with conflicting personalities. Removing oneself from tense social situations during the winter is not a viable option. Travel for even brief periods to escape this confinement is hampered by the extreme cold, darkness, fatigue, and by policies promoting safety and reduction of the risk of accidental injuries. Such a dilemma is illustrated by an account of the Steger International polar expedition in 1986: “Sitting there cold and hungry as the wind snapped the tent walls like a whip, we grumbled among ourselves, certain that the other group was hoarding more than its www.thelancet.com Vol 371 January 12, 2008

share of the additional supply we had gotten from Drep Camp. With a storm raging outside, another one was about to erupt inside our tents. As our suspicions evolved into anger, we shouted over to the other tent group, demanding our full share of the soup.”35 However, the authors further note: “As the accusations shot back and forth like darts, it slowly became apparent to all of us that, in our state of perpetual stress, hunger, and exhaustion, it was impossible for us to look at the issue objectively. When the smoke cleared, it proved to be an innocent matter with a simple explanation.”35 The psychological effects experienced by people on polar expeditions can be categorised as symptoms, syndromes, disorders, and positive effects.

Symptoms Several symptoms are repeatedly reported by people on polar expeditions (panel 1), including headaches, boredom, fatigue, inattention to personal hygiene, reduced motivation with intellectual inertia, and increased appetite resulting in weight gain. Gastrointestinal complaints, rheumatic aches and pains, and increased sensitivity to physical and social stimuli are also common symptoms.14,52 However, the most common symptoms of people undertaking polar expeditions include sleep disruption, impaired cognitive performance, negative affect, and interpersonal tension and conflict. Panel 1: Psychological symptoms experienced by people on polar expeditions Somatic symptoms Fatigue14,17,36 Weight gain17,34 Gastrointestinal complaints13,17 Rheumatic aches and pains13,17 Headaches10,13,14,24 Disturbed sleep (big eye) Difficulty falling asleep15,17,24,37–43 Difficulty staying asleep15,17,24,37–43 Loss of slow-wave sleep44 Loss of rapid eye movement (REM) sleep44,45 Impaired cognition Reduced accuracy and increased response time for cognitive tasks of memory, vigilance, attention, and reasoning13–15,17,34,43,46,47 Easily hypnotised and susceptible to suggestion48,49 Intellectual inertia14,17,34 Spontaneous fugue states (Antarctic stare)17,34 Negative affect Depressed mood12,13,15,17,34,43 Anger and irritability12,13,15,17,34,43 Anxiety12,13,17 Interpersonal tension and conflict Toward group members12,17,18,34,35,50,51 Toward people not in the group8,17,34

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Sleep disruption Difficulty falling or staying asleep, or both (popularly known as big eye) are characteristic of people on polar expeditions, especially at midwinter.15,37–40 A survey by Palinkas34 recorded that 64·1% of people at McMurdo Station in Antarctica reported some difficulty with sleep in winter. Similarly, a summer expedition to the Antarctic noted poor sleep in two of every three participants.41 In a study of Russian miners in Svalbard, Norway, 81% of men and 77% of women reported sleeping problems lasting for at least 2 weeks.42 Other sleep-related studies recorded sizable reductions in the amount of slow-wave and rapid-eye-movement (REM) sleep in Antarctica44,45 and a significant reduction in REM sleep in men working and sleeping in the Arctic.46 These problems can mostly be attributed to disruption of circadian rhythms in both summer41,53 and winter,23 cold exposure,46 and psychosocial stress.15,54 However, other studies noted no change in sleep in people on expiditions in the Antarctic.55,56 Palinkas and colleagues54 reported that total hours of sleep over 24 hr, duration of longest (ie, night-time) sleep event, number of sleep events, time of sleep onset, and quality of sleep remained unchanged over the course of the austral winter (March to October) in Antarctica. However, increasing exposure to total darkness calculated on the basis of station latitude was significantly associated with fewer total hours of sleep, shorter duration of longest sleep event, later time of sleep onset, and reduced quality of sleep.

Cognition impairment Many people on polar expeditions in the Antarctic and Arctic report impairment of memory, difficulty in concentrating, and reduced alertness, seen as reductions in accuracy and increases in response time in standardised tests.14,46,47 During the 1989 winter season at McMurdo, 51·5% of residents reported difficulties with concentration or memory.34 Other studies reported increased susceptibility to suggestion and hypnosis,48,49 and the incidence of spontaneous fugue states.14 These symptoms have been attributed to fatigue,14 absence of environmental stimulation,57 and neurobehavioural effects of exposure to cold.46 However, other studies recorded no reduction in cognitive performance,58 reductions in some elements of performance (eg, accuracy on a memory search task) but not in others (eg, code substitution, reaction time, pattern recognition),59 and a few studies have noted increases in performance after a winter in the Antarctic.60,61

Negative affect Depressed affect is one of the most common symptoms people have on polar expeditions, closely followed by anxiety and irritability. Accounts of polar treks frequently cite instances of people who undergo periods of doubt about their performance or sadness that they are unable to meet personal or group expectations.18,35 Such feelings are also pervasive in the polar research station, despite its greater comfort than shelters used in traditional treks. In 156

the 1989 winter season at McMurdo, 62·1% of residents reported feeling depressed and 47·6% reported feeling more irritable than usual.34 Negative affect is generally transient and resolves without clinical intervention. Yet clinically and statistically significant increases in depressive symptoms are noted during winter in Antarctica.62–64 These symptoms are attributed to poor sleep,47 psychosocial stress15,34,57 and neurobehavioural effects of long-term exposure to cold and darkness.47,64,65 However, other polar expeditions note no increase in depressed affect;66–68 increases in depression or anxiety at the beginning of an expedition that subsequently abate;69 more positive than negative affect;70,71 or decreases in depression either in summer72 or winter.73–75

Interpersonal tension and conflict Although people on polar expeditions often have great social cohesion because of undergoing a common experience,34 interpersonal conflict and tension is the greatest source of stress in polar expeditions.17,18,52 An illustration of such tension is provided in an account of a polar trek: “Adding to the physical misery of scouting was that it often proved to be a thankless job. Team members who were thoroughly exasperated with the horrendous workload of chopping ice and prying, pushing, and pulling the thousand pound sled loads inch by inch for endless hours each day, often thought the scout had the easier job. Minor grumbling erupted from time to time when day after day I was often out of sight of our caravan. Some felt I was copping out of the brunt of the work.”35 Tension or conflict within an expedition can be attributed to social comparisons that are inevitable in every newly formed group,17,34 ostracism of crewmembers who do not adhere to group norms,17,34,76 group heterogeneity characterised by differences in gender77,78or occupation,15,34,52 poor or ineffective leadership,76,79,80 and competition between leaders18,68 or between leaders and followers. Polar expeditions also frequently have some degree of tension or conflict with external organisations. Much of this external tension results from displacement of intragroup tension and conflict.17,34 However, it might also be a response to interference with established routines, delays in arrival of relief parties or supplies, or problems with communication.17,34 Other studies recorded little or no tension between expedition members.67,70–72

Syndromes Explorers in both the Antarctic and Arctic have long noted the occurrence of seasonal variations in the aforementioned symptoms.81 For instance, Americans resident in six Antarctic research stations for whole winters between 1963 and 1974 had significant increases in symptoms as the season progressed.82 Members of the 11th Indian Antarctic scientific expedition reported significant increases in tobacco smoking in March and sleep disturbances in June, reductions in rapport with fellow crew members in September, and satisfaction with www.thelancet.com Vol 371 January 12, 2008

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work and life situations in December and January.39 An analogous pattern of seasonal variation in mood and somatic complaints was reported in Japanese residents at Asuka Station in Antarctica.36 Another study of Japanese residents in the Antarctic noted a decrease in hardiness at the end of the winter.66 These seasonal changes can also be regarded as three distinct syndromes or clusters of symptoms.

Winter-over syndrome The cluster of symptoms consisting of sleep disturbance, impaired cognition, negative affect, and interpersonal tension and conflict experienced by people on polar expeditions in the Antarctic was first referred to as the winter-over syndrome by Strange and Youngman.43 Despite its name, the winter-over syndrome is not a clinical entity, and the severity and duration of symptoms are usually not sufficient to warrant a DSM-IV diagnosis. Rather, it can be more appropriately described as a subclinical condition similar to subclinical depression.83 Several studies have noted that the symptoms of the winter-over syndrome seem to increase after the midpoint of an expedition, with some reduction in symptoms toward the end.50,82,84 This pattern is known as third-quarter phenomenon,85 and seems to be due to psychosocial factors, rather than environmental ones, and is independent of expedition duration. This syndrome results from the realisation that the mission is only half completed, and that a period of isolation and confinement equal to the first half remains. However, this situation has not affected all expeditions, especially polar treks in which the greatest stress occurs around the point of no return (ie, the point at which available supplies are insufficient to allow a return to the point of origin), after which stress seems to diminish, as seen during the Footsteps of Scott expedition in Antarctica: “Our days on the glacier were some of the most pleasant of the journey. The stress we felt on the Barrier was perhaps due as much to the deprivation of the landscape as it was to the uncertainty of what lay ahead. Now we were past half-way and making excellent progress.”18

These changes are known as the polar T3 syndrome, and share many characteristics with subclinical hypothyroidism, including raised thyrotropin-stimulating hormone concentrations and enhanced effects of thyrotropin-releasing hormone.33,87,88 Furthermore, reductions in cognitive performance and increases in negative affect have been effectively treated with low doses of thyroid supplements.47 The cognitive and affective symptoms characteristic of polar T3 syndrome are believed to represent a state of CNS hypothyroidism accompanied by systemic euthyroidism.47,65

Subsyndromal seasonal affective disorder A third pattern of seasonal changes in polar expeditions seems to be related to variations in patterns of daylight and darkness.89 A review of data collated from people who spent an austral winter at Palmer, McMurdo, and South Pole Stations in 1991 showed a significant increase in prevalence of subsyndromal seasonal affective disorder from late austral summer to mid-winter.64 The association between depressive symptoms and time of year is consistent with studies of individuals in the general population that suggest an increased risk of seasonal affective disorder and subsyndromal seasonal affective disorder with decreased exposure to bright light during the winter months.90,91 Light intensity has been associated with suppression of melatonin;92–94 light-dependent Diagnosis

DSM-IV Number Rate per 100 Weighted Code of cases debriefed Rate per 100

Mood disorders

13

4·2

1·7

Major depressive disorder, single episode

296.2

6

1·9

0·8

Major depressive disorder, recurrent

296.3

2

0·6

0·3

Dysthymic disorder

300.4

1

0·3

0·1

Depressive disorder not otherwise specified

311.0

4

1·3

0·5

5

1·6

0·5 0·3

Personality disorders Schizoid personality disorder

301.2

2

0·6

Dependent personality disorder

301.6

2

0·6

0·3

Personality disorder not otherwise specified

301.9

1

0·3

0·1

4

1·3

0·5

Alcohol dependence

303.9

2

0·6

0·3

Polar T3 syndrome

Cannabis abuse

304.3

1

0·3

0·1

A second seasonal pattern of symptoms was seen in a cohort of 22 men and women participating in a study of cold-related changes in thyroid function and their effects on mood. Profile of Mood States86 total mood disturbance scores showed an effect over the 12 months of Antarctic residence, with a sine distribution and two peak values above the mesor, one in November and one in July, and a trough below the mesor in March.65 This cyclic pattern is almost identical to the seasonal variation in serum thyrotropin-stimulating hormone concentrations seen at the polar regions.47 Furthermore, the change in thyroid function in people on polar expeditions is significantly correlated with performance at cognitive tests and mood symptoms.47,65

Alcohol abuse

305.0

1

0·3

0·1

9

2·9

1·1

9

2·9

1·1

12

3·8

1·6 0·8

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Substance-related disorders

Sleep disorders Circadian rhythm sleep disorder

307.45

Adjustment disorders Adjustment disorder with depressed mood

309.0

6

1·9

Adjustment disorder with anxiety

309.24

2

0·6

0·3

Adjustment disorder with mixed emotion or conduct

309.4

2

0·6

0·3

Adjustment disorder unspecified

309.9

2

0·6

0·3

39

12·5

5·2

Total DSM-IV disorders

*Adjusted for differences between military or civilian status, age, and sex of participants in debriefing and all expedition members.

Table: Unadjusted and weighted* prevalence (per 100 people debriefed) of DSM-IV disorders in people on the United States Antarctic Program at end of an austral winter95

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modulation of circulating melatonin concentrations conveys information about the photoperiod.95 The melatonin rhythm is an important transducer of photoperiod information for the timing of many circadian and circannual physiological rhythms,96 including rhythms of energetic arousal, mood, and cognitive performance.97,98

Psychiatric disorders Although these syndromes can be commonplace in people on polar expeditions, they rarely lead to a clinical intervention. Generally, psychiatric disorders have traditionally accounted for 1–5% of all station sick-calls or outpatient visits at research stations in the Antarctic,5 although evidence suggests that this proportion is decreasing.8 Psychiatric debriefings of 313 men and women done at McMurdo and South Pole between 1994 and 1997 revealed that 5·2% of people fulfilled DSM-IV criteria for at least one psychiatric disorder.99 The table shows details of specific disorders. Although these rates are lower than what might be seen in the general population in the USA,100 they are noteworthy because these men and women underwent medical and psychiatric screening before the winter. Norman101 reported a similar prevalence in crew members of British Antarctic Survey stations who did not have psychiatric screening. In the Arctic, Rosen, et al102 reported that 5·2% of men and 8·9% of women stationed at an army installation in Alaska met the criteria for seasonal affective disorder. However, the rates in this largely non-indigenous population are comparable with the 6·3% prevalence of seasonal affective disorder in a group of Inuit living in the Canadian Arctic.103

Positive effects Although people on polar expeditions might experience symptoms, syndromes, and disorders in varying degrees, they will probably also have positive effects. These effects can be divided into two major categories, each of which can be further subdivided. The two main categories are (a) the inherently enjoyable characteristics of the situation, and (b) the positive reactions to challenges of the environment and having encountered and successfully surmounted these challenges. Although very little research has focused on either of these positive effects, especially when compared with work that emphasises negative effects and consequences, some research and a substantial body of anecdotal evidence (autobiographies, logbooks, letters, diaries, and interviews) document their importance. One point to remember is that positive and negative reactions are not mutually exclusive. People can enjoy and benefit from an experience even though they also show signs of discomfort or psychological symptoms, and vice versa. Studying positive aspects is not intended to deny the existence of negative ones, but assessment of either alone results in an incomplete and therefore inaccurate picture of polar service. 158

Panel 2: Positive characteristics of the polar environment109 Natural grandeur, vastness, and beauty; feeling small and insignificant and (paradoxically) strength Excitement of encountering and learning about unknown and unusual terrain, weather, and fauna Efficiency; most needed facilities easily accessible Coziness; cocooning inside the comfortable station Balance of novelty and familiarity: sufficient novelty in routines and in natural environment, with sufficiently familiar capsule environment Improvisation: trying new ways of working without accustomed restrictions Free time; for recreation, self-improvement, hobbies, exercise, thinking Time out from daily hassles and other negative aspects of home-life

Even amidst the acknowledged dangers and deprivations of the early polar explorations, expeditioners frequently referred to the beauty and grandeur of the land, ice, and sea, the camaraderie and mutual support of the team, the admirable qualities of their leader, and the thrill of facing and overcoming the challenges of the environment.81 Those who study present-day polar sojourners report very similar positive reactions.104 Many studies have reported high emotional adjustment and positive feelings in expedition members in both summer68,72 and winter.66,105 One study of French stations noted predominantly favourable ratings of the recreational and leisure facilities of stations, the quality of the food, and the individual’s success in adjusting to the polar situation.50 An Australian survey of 104 Antarctic residents reported that although a greater range of negative reactions was listed, most of them were infrequent; positive events were much more frequent.105 A study of three Norwegian physicians who crossed the inland glacier of Greenland on skis reported a significant increase in subjective wellbeing in the second half of the trip.106 One important piece of evidence of the overall benefit of the polar experience is that so many people volunteer for repeated assignments and are perturbed when asked to consider never going back;105,107 as one researcher noted, “Almost every member of the winter party considered his Antarctic stay as one of the best experiences of his life.”108 Some frequently mentioned sources of polar enjoyment are listed in panel 2. As in other extreme and unusual environments, several kinds of positive reactions and consequences are seen in people on polar expeditions. Resilience and coping take place while in the environment; salutogenesis and post-return growth refer to the long-term effects of the experience. Evidence of successful coping strategies for the physical and psychosocial environmental conditions of polar expeditions was obtained from investigations of mood disturbances during early and late winter in 657 navywww.thelancet.com Vol 371 January 12, 2008

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enlisted men who spent a winter in Antarctica between 1963 and 1974. These studies recorded that symptoms of the winter-over syndrome were inversely associated with the altitude, latitude, and mean yearly temperature of the research stations.82,110 An increase in symptom scores from early to late winter was seen in 63·0% of these individuals; no change in symptom scores was noted in 8·5%; and 28·4% had a decrease in symptom scores. People who had a decrease in symptoms had less need for social interaction (eg, low need to include others, low need to be included by others, and low need to express affection to others) than those whose symptoms increased.82 Coping strategies, whether transferred from normal life to the polar regions or developed in these regions, are a source of pride and self-esteem because they help the crew surmount challenges. Early sailors in the polar seas, and both Arctic and Antarctic explorers of the heroic age, used a range of tactics to increase enjoyment and knowledge, including amateur theatricals, musicals, ship’s or expedition’s newspapers, and lectures on topics including the polar science of the day.111 Present-day crews, at sea and on the ice, engage in similar activities, and additionally have access to television, video, telephones, and the internet. These activities seem to effectively facilitate coping, stress reduction and pleasure enhancement.108 Salutogenesis and post-return growth are related to the ideas of eustress, based on Selye’s112 notion of stress that has positive effects (as opposed to distress): they are also related to the positive psychology movement.113 The important distinction between salutogenesis and post-return growth on the one hand and resilience and coping on the other is that resilience and coping refer to ways of avoiding or warding off negative effects, whereas the salutogenesis and post-return growth refer to improvements in psychological characteristics or processes. Salutogenesis is a term coined by the late Israeli sociologist, Aaron Antonovsky,114 who contrasted it with the word pathogenesis. Salutogenic experiences therefore are those that lead to heightened strength, depth of insight, improved relations with others, increased self-confidence and humane values, and many other favourable changes. Such experiences are, as the term implies, health-generating; pathogenic experiences have the opposite effect, they are illness-generating. Comparable events or experiences can be pathogenic or salutogenic for different people, or for one person at different times. Post-return growth is a paraphrase of the label, posttraumatic growth, originated by Tedeschi and Calhoun.115 The basic idea is that traumatic experiences can lead to positive changes in characteristics such as coping skills and resilience, self-esteem, self-confidence, changes in perspective and values, and increased self-awareness. If positive changes happen to people who survive extreme www.thelancet.com Vol 371 January 12, 2008

Panel 3: Salutogenic after effects of polar expeditions109 Affiliation, intimacy with fellow crew members Sense of personal achievement Cooperativeness in work and play Striving toward important goals Courage, resoluteness, indomitability Excitement, curiosity Increased self-esteem and self-efficacy from challenges sought deliberately Hardiness, resiliency, coping Improved health Group solidarity, cohesiveness, shared values Increased individuality, reduced conformity Reflection, contemplation Ability to set and achieve higher goals, and changes in thinking Increased sense of humanity

trauma, such as military service, persecution, violent crime, or child abuse, they might also happen to those who return from challenging but not traumatic situations, such as time spent in an extreme or unusual environment.109,116 The best evidence of salutogenesis or post-return growth thus far is the finding that American naval crew who spent winter in the Antarctic had better health records after their return and more successful careers than a control group who had volunteered for Antarctic assignments and passed the screening tests, but had never been deployed.117 As a group, those stationed in Antarctica had 20% fewer first hospital admissions in the remainder of their time in the military (5–13 years). A salutogenic outcome could also result from achievement of the polar expedition’s goals. An example of such an outcome is detailed in a study, by Atlis, et al,118 of two women who successfully traversed the length of the Antarctic continent. Their main motivations for the expedition were not only the challenge of the environment, but also to be role models to girls and women, and to provide an educational curriculum to schools after the expedition. Panel 3 shows other psychosocial states that might result from salutogenic experiences and post-return growth.

Prevention and promotion Expedition leaders have tried several different techniques, including many leisure activities, for prevention of psychological distress and poor performance, and promotion of team member wellbeing. Occasionally, measures intended to reduce stress and improve wellbeing, such as availability of alcohol during the polar winter, in fact reduced individual performance and increased social tension and conflict.57 Engaging in training, both individually35 and as a crew34 also facilitates psychological adaptation to the expedition through enhanced self-confidence. Availability of information and 159

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support to family members, as is provided to members of the Australian National Antarctic Research Expedition119 also can enable coping in people on polar expeditions by improvement of access to social support and reductions in the stress associated with separation from family. Perhaps the most effective method for prevention of psychogenic effects during polar expeditions is a programme of psychological screening and selection of participants. Such programmes are rarely, if ever, adopted for treks and camps. Several nations operating research stations in the Antarctic have such programmes for individuals who expect to stay for 12 months or longer, including the austral winter when medical evacuation is exceedingly difficult if not impossible. These programmes typically consist of structured interviews by psychiatrists or clinical psychologists, standardised psychometric instruments such as the Minnesota Multiphasic Personality Inventory120 and the Michigan Alcoholism Screening Test,121 and reviews of medical and employment records. People on expeditions generally have low prevalence of psychiatric disorders and low proportion of total outpatient visits, thus these programmes are generally considered to be successful at detecting individuals who would have trouble coping with polar life. Screening and selection procedures including preexpedition psychiatric evaluations to select out people who could have psychiatric disorders are but one element of the psychological support provided for people on polar expeditions. Other elements include; psychiatrists and clinical psychologists consulting with expedition physicians and crew members via telecommunications networks, both in response to disasters and emergencies Panel 4: Characteristics of the ideal person for polar expeditions Short expeditions High motivation to achieve16,52,70,123 High sense of adventure123,124 Low susceptibility to anxiety71,125 Long expeditions Aged older than 30 years51,52,126 Emotionally stable52 Few symptoms of depression62,126,127 Low neuroticism127,128 Introverted but socially adept15,127 Satisfied with social support16,62 Not greatly extraverted or assertive43,127 No great need for social interaction52,127 Low demands for social support10,52,127 Sensitive to needs of others10,34,82,127 Desire for optimistic friends127 High tolerance of little mental stimulation129 Does not become bored easily10,82,127 High tolerance to lack of achievement82,127 Low need of order127

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affecting the entire expedition and in response to individual symptoms; training of crew members in personal coping strategies, teamwork and leadership; and giving psychological support to trauma victims;122 medical evacuation by air if necessary and possible (usually restricted to the summer months); and debriefings by clinicians after the expedition to intervene in crises and give reassurance before the return home. Additionally, a long tradition of research has identified individual characteristics that predict for optimum performance and adaptation in polar expeditions (panel 4).16,52,126,130 Several of the individual traits are associated with high emotional stability, task ability, and social compatibility in long-term (ie, station)51,82,127,129,131 and short-term (ie, treks and field camp)123–125 expeditions. Characteristics of effective groups include appropriate and effective leadership, similarities in approach to problem-solving, respect for each other’s opinions, and shared decisionmaking.51,129,132,133 Nevertheless, in addition to individuals being selectedout of some types of expedition, personality traits generally have little ability to predict behaviour and performance on polar expeditions because people who want do go on expedition are generally highly motivated volunteers who show smaller variation in personality traits than typically seen in the general population.3,16,128 Baseline measures of personality, stress, and coping are weak prospective predictors of behaviour and performance during the winter because such performance is affected more by the situational characteristics of isolation, confinement, and extreme environments than by stable traits of individuals.134,135 These characteristics include the stressors (eg, isolation, confinement), and the scarcity of resources necessary to cope with these stressors.

Conclusion Over the past century, we have learned much about the psychological changes experienced by polar expeditioners. These changes range from the harmful or pathogenic to the beneficial or salutogenic. For most expeditioners, the rewards have far outweighed the risks. Nevertheless, continued research on the psychological effects of polar expeditions is important because it helps us to better understand some of the underlying principles of behaviour in any environment and in particular, behaviour in isolated and confined environments. This understanding is seen as especially important in situations like long-duration missions in space where the opportunities for doing similar investigations is limited by logistical constraints and small numbers of participants. This research will also be increasingly important as more and more people, old and young, seek out the challenge and beauty of the circumpolar regions. Improvement of select-out procedures can reduce the frequency and operational effects of psychiatric disorders and other pathogenic changes, although improvement of select-in procedures can improve quality of life, enhance www.thelancet.com Vol 371 January 12, 2008

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task performance, and increase the likelihood of beneficial or salutogenic changes. Such improvements would include the development of guidelines for the screening and selection of individuals for various types of polar expeditions. Assessment and classification of adaptive and maladaptive forms of behaviour that are specific to polar expeditions, developing protocols and resources necessary to provide psychological support, and training polar expeditioners to cope with the stress of isolation, confinement, and harsh physical environments is also recommended. Such procedures should be designed to predict for as well as promote the three essential components of successful polar expeditions: task ability, emotional stability, and social compatibility. Conflict of interest statement We declare that we have no conflict of interest. Acknowledgments This work was supported by the US National Science Foundation (OPP-00-90343). References 1 Connor S. Global warming ‘past the point of no return’. The Independent (UK): Sept 16, 2005. 1 2 Harrison AA, Clearwater YA, McKay CP. Introduction. In: Harrison AA, Clearwater YA, McKay CP, eds. From Antarctica to outer space: life in isolation and confinement. New York: Springer-Verlag, 1991: 1–6. 3 Rivolier J. L’homme dans l’espace: une approche psycho-écologique des vols habités. Paris: Presses Universitaires de France, 1997. 4 Institute of Medicine. Bioastronautics roadmap: a risk reduction strategy for the human exploration of space. Washington, DC: National Academy Press, 2005. 5 Lugg D. Behavioral health in Antarctica: implications for long-duration missions in space. Aviat Space Environ Med 2005; 76 (suppl 6): B89–93. 6 Jacka F, Jacka E, eds. Mawson’s Antarctic diaries. Sidney: Allen & Unwin Australia, 1988. 7 Cook FA. Through the first Antarctic night 1898–1899. New York: Doubleday, Page & Co, reprinted in 1998 Pittsburgh, PA: Polar Publishing Company. 8 Palinkas LA. The psychology of isolated and confined environments: understanding human behavior in Antarctica. Am Psychol 2003; 58: 353–63. 9 Guthridge LF. Ghosts of Cape Sabine: the harrowing true story of the Greely Expedition. New York: Berkeley Books, 2000. 10 Nardini JE, Herrmann RS, Rasmussen JE. Navy psychiatric assessment program in the Antarctic. Am J Psychiatry 1962; 119: 97–105. 11 Behrendt JC. Innocents on the ice: a memoir of Antarctic exploration, 1957. Boulder: University Press of Colorado, 1998. 12 Gunderson EK. Emotional symptoms in extremely isolated groups. Arch Gen Psychiatry 1963; 14: 362–68. 13 Law P. Personality problems in Antarctica. Med J Aust 1960; 47: 273–82. 14 Mullin CS. Some psychological aspects of isolated Antarctic living. Am J Psychiatry 1960; 117: 323–25. 15 Palmai G. Psychological observations on an isolated group in Antarctica. Br J Psychiatry 1963; 109: 364–70. 16 Taylor AJW. Antarctic psychology. Wellington: Department of Scientific and Industrial Research, 1987. 17 Natani K, Shurley JT. Sociopsychological aspects of a winter vigil at south polar station. In: Gunderson EKE, ed. Human adaptability to Antarctic conditions. Washington, DC: American Geophysical Union, 1974: 89–114. 18 Mear R, Swan R. In the footsteps of Scott. London: Jonathan Cape, 1987. 19 Sproule J, Jette M, Rode A. Medical observations of members of the Soviet/Canadian 1988 Polar Bridge Expedition. Arctic Med Res 1991; 50 (suppl): 489–90.

www.thelancet.com Vol 371 January 12, 2008

20 21

22

23

24

25

26

27 28 29

30

31

32

33

34 35 36

37

38

39

40

41

42

43 44

45

Cattermole TJ. The incidence of injury with the British Antarctic Survey, 1986–1995. In J Circumpolar Health 2001; 60: 72–81. Cooke FJ, Sabin C, Zuckerman JN. A study of the incidence of accidents occurring during an Arctic expedition: another important aspect of travel medicine? J Travel Med 2000; 7: 205–07. Broadway JW, Arendt J. Seasonal and bright light changes of the phase position of the human melatonin rhythms in Antarctica. Arctic Med Res 1988; 47 (suppl 1): 201–03. Kennaway DJ, Van Dorp CF. Free-running rhythms of melatonin, cortisol, electrolytes, and sleep in humans in Antarctica. Am J Physiol 1991; 260: R1137–44. Guenter CA, Joern AT, Shurley JT, Pierce CM. Cardiorespiratory and metabolic effects in men on the south polar plateau. Arch Intern Med 1970; 125: 630–37. O’Brien C, Frykman PN. Peripheral responses to cold: case studies from an Arctic expedition. Wilderness Environ Med 2003; 14: 112–19. Harinath K, Malhotra AS, Pal K, Prasad R, Kumar R, Sawhney RC. Autonomic nervous system and adrenal response to cold in man at Antarctica. Wilderness Environ Med 2005; 16: 81–91. Cattermole TJ. The epidemiology of cold injury in Antarctica. Aviat Space Environ Med 1999; 70: 135–40. Hassi J, Makinen TM. Frostbite: occurrence, risk factors and consequences. Int J Circumpolar Health 2000; 59: 92–98. Steine K, Roseth AG, Sandbaek G, et al. Increased cortisol levels, frostbite and effects on the muscles and skeleton during extreme polar conditions. Tidsskr Nor Laegeforen 2003; 123: 3529–32. Muller HK, Lugg DJ, Quinn D. Cell mediated immunity in Antarctic wintering personnel: 1984–1992. Immunol Cell Biol 1995; 73: 316–20. Shearer WT, Lee BN, Cron SG, et al. Suppression of human anti-inflammatory plasma cytokines IL-10 and IL1-RA with elevation of proinflammatory cytokine IFN-γ during the isolation of the Antarctic winter. J Allergy Clin Immunol 2002; 109: 854–57. Leppaluoto J, Paakkonen T, Korhonen I, Hassi J. Pituitary and autonomic responses to cold exposures in man. Acta Physiol Scand 2005; 184: 255–64. Reed HL, Burman KD, Shakir KMM, O’Brian JT. Alterations in the hypothalamic-pituitary-thyroid axis after prolonged residence in Antarctica. Clin Endocrinology 1986; 25: 55–65. Palinkas LA. Going to extremes: the cultural context of stress, illness and coping in Antarctica. Soc Sci Med 1992; 35: 651–64. Steeger W, Schurke P. North to the Pole. New York: Times Books, 1987. Ikegawa M, Kimura M, Makita K, Itokawa Y. Psychological studies of a Japanese winter-over group at Asuka Station, Antarctica. Aviat Space Environ Med 1998; 69: 452–60. Joern AT, Shurley JT, Brooks RE, Guenter CA, Pierce CM. Short-term changes in sleep patterns on arrival at the south polar plateau. Arch Intern Med 1970; 125: 649–54. Shurley JT, Pierce CM, Natani, K, Brooks RE. Sleep and activity patterns at South Pole station. Arch Gen Psychiatry 1970; 22: 385–89. Bhargava R, Mukerji S, Sachdeva U. Psychological impact of the Antarctic winter on Indian expeditioners. Environ Behav 2000; 32: 111–27. Usui A, Obinata I, Ishizuka Y, Okado T, Fukuzawa H, Kanba S. Seasonal changes in human sleep-wake rhythm in Antarctica and Japan. Psychiatry Clin Neurosci 2000; 54: 361–62. Gander PH, MacDonald JA, Montgomery JC, Paulin MG. Adaptation on sleep and circadian rhythms to the Antarctic summer: a question of zeitgeiber strength. Aviat Space Environ Med 1991; 62: 1019–25. Nilssen O, Lipton R, Brenn T, Hoyer G, Boiko E, Tkatchev A. Sleeping problems at 78 degrees north: the Svalbard Study. Acta Psychiatr Scand 1997; 95: 44–48. Strange RE, Youngman SA. Emotional aspects of wintering over. Antarct J US 1971; 6: 255–57. Natani K, Shurley JT, Pierce CM, Brooks RE. Long-term changes in sleep patterns in men on the south polar plateau. Arch Intern Med 1970; 235: 655–59. Paterson RA. Seasonal reduction of slow-wave sleep at an antarctic coastal station. Lancet 1975; 1: 468–69.

161

Review

46

47

48 49

50

51 52

53

54 55 56 57 58

59

60 61

62

63 64 65

66

67

68

69

70

71

162

Angus RG, Pearce DG, Buguet AG, Olsen L. Vigilance performance of men sleeping under arctic conditions. Aviat Space Environ Med 1979; 50: 692–96. Reed HL, Reedy KR, Palinkas LA, et al. Impairment in cognitive and exercise performance during prolonged Antarctic residence: effect of thyroxine supplementation in the Polar triiodothyronine syndrome. J Clin Endocrinol Metab 2001; 86: 110–16. Barabasz AF. EEG alpha, skin conductance and hyponotizability in Antarctica. Int J Clin Exp Hypnosis 1980; 28: 63–74. Barabasz M, Barabasz AF, Mullin CS. Effects of brief Antarctic isolation on absorption and hypnotic susceptibility – preliminary results and recommendations. Int J Clin Exp Hypnosis 1983; 31: 235–38. Stuster J. Bachelard C, Suedfeld P. The relative importance of behavioral issues during long-duration ICE missions. Aviat Space Environ Med 2000; 71 (Suppl 9): A17–25. McGuire F, Tolchin S. Group adjustment at the South Pole. J Ment Sci 1961; 107: 954–60. Gunderson EK. Psychological studies in Antarctica. In: Gunderson EKE, ed. Human adaptability to Antarctic conditions. Washington, DC: American Geophysical Union, 1974: 115–31. Steel GD, Callaway M, Suedfeld P, Palinkas LA. Human sleep-wake cycles in the high Arctic: effects of unusual photoperiodicity and time disentrainment. Biol Rhythm Res 1995; 26: 582–92. Palinkas LA, Houseal M, Miller C. Sleep and mood during a winter in Antarctica. Int J Circumpolar Health 2000; 59: 63–73. Buguet A, Rivolier J, Jouvet M. Human sleep patterns in Antarctica. Sleep 1987; 10: 374–82. Bogoslovskii MM. Polar insomnia on the antarctic continent. Lancet 1974; 1 (7856): 503–04. Palinkas LA. Sociocultural influences on psychosocial adjustment in Antarctica. Med Anthropol 1989; 10: 235–46. Le Scanff C, Larue J, Rosnet E. How to measure human adaptation in extreme environments: the case of Antarctic wintering-over. Aviat Space Environ Med 1997; 68: 1144–49. Hodgdon JA, Hesslink RL, Hackney AC, Vickers RR, Hilbert RP. Norwegian military field exercises in the arctic: cognitive and physical performance. Arctic Med Res 1991; 50 (suppl): 132–36. Xue Z, Xue Q. Psychological changes of fifteen Chinese Antarctic Research Expedition members. Antarct Rec 1994; 5: 27–33. Defayolle M, Boutelier C, Bachelard C, Rivolier J, Taylor AJ. The stability of psychometric performance during IBEA. J Human Stress 1985; 11: 157–60. Palinkas LA, Browner D. Effects of prolonged isolation in extreme environments on stress, coping, and depression. J Appl Soc Psychology 1995; 25: 557–76. Palinkas LA, Cravalho M, Browner D. Seasonal variation of depressive symptoms in Antarctica. Acta Psychiat Scand 1995; 91: 423–29. Palinkas LA, Houseal M, Rosenthal NE. Subsyndromal seasonal affective disorder in Antarctica. J Nerv Ment Dis 1996; 184: 530–34. Palinkas LA, Reed HL, Reedy KR, Do NV, Case HS, Finney NS. Circannual pattern of hypothalamic-pituitary-thyroid (HPT) function and mood during extended Antarctic residence. Psychoneuroendocrinol 2001; 26: 421–31. Weiss K, Suedfeld P, Steel GD, Tanaka M. Psychological adjustment during three Japanese Antarctic research expeditions. Environ Behav 2000; 32: 142–56. Peri A, Scarlata C, Barbarito M. Preliminary studies on the psychological adjustment in the Italian Antarctic summer campaigns. Environ Behav 2000; 32: 72–83. Leon GR, McNally C, Ben-Porath YS. Personality characteristics, mood, and coping patterns in a successful North Pole expedition team. J Res Personality 1989; 23: 162–79. Steine S, Steine K, Sandbaek G, Roseth AG. A polar expedition in challenging circumstances—experiences and psychological reactions. Tidsskr Nor Laegeforen 2003; 123: 3524–28. Kahn PM, Leon GR. Group climate and individual functioning in an all women’s Antarctic expedition team. Environ Behav 1994; 26: 669–97. Leon GR, Atlis MM, Ones DS, Magor G. A 1-year, three-couple expedition as a crew analog for a Mars mission. Environ Behav 2002; 34: 672–700.

72

73

74

75 76 77

78 79 80

81 82

83

84 85

86

87

88

89 90

91

92 93

94

95

96

Palinkas LA, Suedfeld P, Steel GD. Psychological functioning among members of a small polar expedition. Aviat Space Environ Med 1995; 66: 943–50. Palinkas LA, Johnson JC, Boster JS, Houseal M. Longitudinal studies of behavior and performance during a winter at the South Pole. Aviat Space Environ Med 1998; 69: 73–77. Palinkas LA, Johnson JC, Boster JS, et al. Cross-cultural differences in psychosocial adaptation to isolated and confined environments. Aviat Space Environ Med 2004; 75: 973–80. Palinkas LA, Houseal M. Stages of change in mood and behavior during a winter in Antarctica. Environ Behav 2000; 32: 128–41. Johnson JC, Boster JS, Palinkas LA. The evolution of networks in extreme and isolated environments. J Math Sociol 2003; 27: 89–121. Rosnet E, Jurion S, Cazes G, Bachelard C. Mixed-gender groups: coping strategies and factors of psychological adaptation in a polar environment. Aviat Space Environ Med 2004; 75 (suppl 7): C10–3. Leon GR. Men and women in space. Aviat Space Environ Med 2005; 76 (suppl 6): B84–88. Stuster J. Bold endeavors: lessons from polar and space exploration. Annapolis, MD: Naval Institute Press, 1996. Wood J, Schmidt L, Lugg D, Ayton J, Phillips T, Shepanek M. Life, survival, and behavioral health in small closed communities: 10 years of studying isolated Antarctic groups. Aviat Space Environ Med 2005; 76 (suppl 6): B89–93. Mocellin JSP, Suedfeld P. Voices from the ice: diaries of polar explorers. Environ Behav 1991; 23: 704–22. Palinkas LA, Gunderson EKE, Johnson JC, Holland AW. Behavior and performance on long-duration spaceflights: evidence from analogue environments. Aviat Space Environ Med 2000; 71 (suppl 9): A29–36. Judd LL, Schettler PJ, Akiskal HS. The prevalence, clinical relevance, and public health significance of subthreshold depressions. Psychiat Clin N Am 2002; 25: 685–98. Sandal GM. Coping in Antarctica: is it possible to generalize results across settings? Aviat Space Environ Med 2000; 71 (suppl 9): A37–43. Bechtel RB, Berning A. The third-quarter phenomenon: do people experience discomfort after stress has passed? In: Harrison AA, Clearwater YA, McKay CP, eds. From Antarctica to outer space: life in isolation and confinement New York: Springer-Verlag, 1991: 261–66. McNair DM, Lorr M, Droppleman LF. EdITS manual for the Profile of Mood States, revised. San Diego: Educational and Industrial Testing Service, 1992. Xu C, Zhu G, Xue QF, et al. Effect of the Antarctic environment on hormone levels and mood of the 16th Chinese expeditioners. Int J Circumpolar Health 2003; 62: 255–67. Reed HL, Silverman ED, Shakir KM, Dons R, Burman KD, O’Brian JT. Changes in serum triiodothyronine (T3) kinetics after prolonged Antarctic residence: the Polar T3 Syndrome. J Clin Endocrinol Metab 1990; 70: 965–74. Yoneyama S, Hashimoto S, Honma K. Seasonal changes of human circadian rhythms in Antarctica. Am J Physiol 1999; 277: R1091–97. Kasper S, Wehr TA, Bartko JJ, Gaist PA, Rosenthal NE. Epidemiologic findings of seasonal changes in mood and behavior. A telephone survey of Montgomery County, Maryland. Arch Gen Psychiatry 1989; 46: 823–33. Magnusson A, Partonen T. The diagnosis, symptomatology, and epidemiology of seasonal affective disorder. CNS Spectr 2005; 10: 625–34 Arendt J. Melatonin: characteristics, concerns, and prospects. J Biol Rhythms 2005; 20: 291–303. Brainard GC, Lewy AJ, Menaker M, et al. Dost-response relationship between light irradiance and the suppression of plasma melatonin in human volunteers. Brain Res 1988; 454: 212–18. Leppaluoto J, Sikkila K, Meyer-Rochow VB, Hassi J. Low melatonin secretion associates with albedo in circumpolar environments. J Pineal Res 2003; 35: 158–62. Brainard CG, Gaddy JR, Barker FM, Hanifin JP, Rollag MD. Mechanisms in the eye that mediate the biological and therapeutic effects of light in humans. In: Wetterberg L, ed. Light and biological rhythms in man. New York: Permagon, 1993: 29–54. Lewy AJ, Sack RL, Singer CM. Melatonin, light and chronobiological disorders. Ciba Foundtn Symp 1985; 117: 231–52.

www.thelancet.com Vol 371 January 12, 2008

Review

97 98

99

100

101

102

103

104 105

106

107 108

109 110

111

112 113 114 115

Thayer RE. The biopsychology of mood and arousal. New York: Oxford University Press, 1989. Wirz-Justice A, Graw P, Krauchi K, Haug HJ, Leonhart G, Brunner DP. Effect of light on unmasked circadian rhythms in winter depression. In: Wetterberg L, ed. Light and biological rhythms in man. New York: Permagon, 1993; 385–93. Palinkas LA, Glogower FG, Dembert M, Hansen K, Smullen R. Incidence of psychiatric disorders after extended residence in Antarctica. Int J Circumpolar Health 2004; 63: 157–68. Kessler RC, McGonagle KA, Zhao S, et al. Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Results from the National Comorbidity Survey. Arch Gen Psychiatry 1994; 51: 8–19. Norman JN. A comparison of the patterns of illness and injury occurring on offshore structures in the northern North Sea and the stations of the British Antarctic survey. Arctic Med Res 1991; 50: 719–21. Rosen L, Knudson KH, Fancher P. Prevalence of seasonal affective disorder among U.S. Army soldiers in Alaska. Mil Med 2002; 167: 581–84. Haggarty JM, Cernovsky Z, Husni M, Minor K, Kermeen P, Merskey H. Seasonal affective disorder in an Arctic community. Acta Psychiatr Scand 2002; 105: 378–84. Bouton K. A reporter at large: south of 60 degrees south. The New Yorker 1981; 42–122. Wood J, Hysong SJ, Lugg DJ, Harm DL. Is it really so bad? A comparison of positive and negative experiences in Antarctic winter stations. Environ Behav 2000; 32: 84–110. Sandbaek G, Steine K, Roseth AG, Falch JA, Steine S. Skiing over Greenland – physical and psychological changes. Tidsskr No Laegenforen 1997; 117: 1104–07. Steel GD. Polar bonds: environmental relationships in the polar regions. Environ Behav 2000; 32: 796–816. Oliver DC. Psychological effects of isolation and confinement of a winter-over group at McMurdo Station, Antarctica. In: Harrison AA, Clearwater YA, McKay CP, eds. From Antarctica to outer space: life in isolation and confinement. New York: Springer-Verlag, 1991: 217–25. Suedfeld P. Applying positive psychology in the study of extreme environments. Hum Perf Extrem Environ 2002; 6: 21–5 Palinkas LA. Effects of physical and social environment on the health and well-being of Antarctic winter-over personnel. Environ Behav 1991; 23: 782–99. Johnson PJ, Suedfeld, P. Non-work activities of Arctic whalers and explorers: coping with stress through creating microcosms of home and family. Hist Fam 1996; 1: 41–62. Selye H. Stress without distress. New York: New American Library, 1974. Snyder CR, Lopez SJ, eds. Handbook of positive psychology. Oxford UK: Oxford University Press, 2002. Antonovsky A. Unraveling the mystery of health: how people manage stress and stay well. San Francisco: Jossey-Bass, 1987. Tedeschi RG, Calhoun LG. Trauma and transformation: growing in the aftermath of suffering. Thousand Oaks, CA: Sage, 1995.

www.thelancet.com Vol 371 January 12, 2008

116 Suedfeld P. Invulnerability, coping, salutogenesis, integration: four phases of space psychology. Aviat Space Environ Med 2005; 76 (Suppl 6): B61–73. 117 Palinkas LA. Health and performance of Antarctic winter-over personnel: a follow-up study. Aviat Space Environ Med 1986; 57: 954–59. 118 Atlis MM, Leon GR, Sandal G M, Infante M. Decision processes and interactions during a two-woman traverse of Antarctica. Environ Behav 2004; 36: 402–23. 119 Australian Antarctic Division. Expeditioner handbook 2006–07. http://www.aad.gov.au/default.asp?casid=16006 (accessed Jan 22, 2007). 120 Dahlstrom WG, Welsh GS, Dahlstrom LE. An MMPI handbook. Minneapolis: University of Minnesota Press, 1975. 121 Alexander D, Mangelsdorff AD. Screening alcohol abuse potential among Army reservists with the Short Michigan Alcoholism Screening Test. Mil Med 1994; 159: 595–600. 122 Taylor AJW. Psychological adaptation to the polar environment. Int J Circumpolar Health 1998; 57: 58–68. 123 Pope FE, Rogers TA. Some psychiatric aspects of an Arctic survival experiment. J Nerv Ment Dis 1968; 146: 433–45. 124 Leon GR. Individual and group process characteristics of polar expedition teams. Environ Behav 1991; 23: 723–48. 125 Mocellin JS, Suedfeld P, Bernaldez JP, Barbarito ME. Levels of anxiety in polar environments. J Environ Psychol 1991; 11: 265–75. 126 Gunderson EK, Kapfer EL. The predictive validity of clinical ratings for an extreme environment. Br J Psychiatry 1966; 112: 405–12. 127 Palinkas LA, Gunderson EKE, Holland AW, Miller C, Johnson JC. Predictors of behavior and performance in extreme environments: the Antarctic Space Analogue Program. Aviat Space Environ Med 2000; 71: 619–25. 128 Steel GD, Suedfeld P, Peri A, Palinkas LA. People in high latitudes: the “Big Five” personality characteristics of the circumpolar sojourner. Environ Behav 1997; 29: 324–47. 129 Biersner RJ, Hogan R. Personality correlates of adjustment in isolated work groups. J Res Personality 1984; 18: 491–96. 130 Sandal GM, Vaernes R, Bergan T, Warncke M, Ursin H. Psychological reactions during polar expeditions and isolation in hyperbaric chambers. Aviat Space Environ Med 1996; 67: 227–34. 131 Rosnet E, Le Scanff C, Sagal M. How self-image and personality affect performance in an isolated environment. Environ Behav 2000; 32: 18–31. 132 Leon GR, Sandal GM. Women and couples in isolated extreme environments: applications to long-duration missions. Acta Astronaut 2003; 53: 259–67. 133 Schmidt LL, Wood J, Lugg DJ. Team climate at Antarctic research stations 1996–2000: leadership matters. Aviat Space Environ Med 2004; 75: 681–87. 134 Carver CS, Scheier MF. Situational coping and coping dispositions in a stressful transaction. J Pers Soc Psychol 1994; 66: 184–95. 135 Holahan CJ, Moos RH. Personal and contextual determinants of coping strategies. J Pers Soc Psychol 1987; 52: 946–55.

163