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Section 11. Mental Disorders – Introduction
S E C T I O N
11
MENTAL DISORDERS INTRODUCTION Mary V. Seeman INTRODUCTION Men and women differ in the prevalence and severity of mental illnesses that they suffer from. This opinion needs to be stated with caution because the diagnosis of a specific mental illness is primarily based on symptoms reported by the patient. More or less ‘neutral’ parties such as clinicians and family members add their observations, but ‘harder’ evidence from biopsies, blood tests, or diagnostic brain changes are rarely available to distinguish among categories of psychiatric illness. To complicate things further, there is considerable overlap in symptoms among differently named illnesses, and overlap also exists between what we determine to be illness and what we consider to be within the range of health. The divisions between wellness and illness, and among psychiatric illnesses, can be relatively arbitrary. Because symptoms fluctuate, they are unreliable anchors. Because some individuals are readier to disclose symptoms than others or more disposed to seek help for them, there may be many, equally ill, who are not identified. For many DSM-IV diagnoses, symptoms alone are not sufficient to identify someone as ill; an impairment in function must also exist. That can be problematic since adequate functioning depends on many factors besides the severity of an illness, e.g. socioeconomic status, intelligence, personality traits, family support or social role within the family or community. For all these reasons, although male/female differences in the prevalence of many psychiatric disorders appear to exist, it is probably premature to state unequivocally that they do. If we suspend disbelief, however, and assume that sex differences are a fact, such differences can provide clues to etiology. We can then search for effects of exposure to distinct environments,
hormonal effects, gene dosage effects, genetic imprinting effects or microchimerism (the passage of antigens across the placenta during pregnancy). Most likely, sex differences in disease will prove to be based on combinations of the above. We no longer speak of the differential effects of nature versus nurture, since the two are one: vulnerabilities in our DNA can be overcome or exaggerated by what we experience. The chapters in this section focus on mood disorders, schizophrenia, post-traumatic disorders, eating disorders, and addictive disorders. Alzheimer’s disease is covered elsewhere in this volume, in the section on aging. Social and reproductive contributions to women’s health are also addressed in other sections. Not addressed are dissociative disorders such as dissociative amnesia, or dissociative identity disorder, both more common in women than in men although the diagnostic category is controversial; the DSM-V workgroup is reconsidering it. Classification of personality disorders is also being reconsidered and these disorders are likewise not addressed in this section. Personality disorders as a group refer to stable, significant impairments in interpersonal functioning. The DSM-IV categories of histrionic (emotional lability, manipulativeness, attention seeking) and dependent (submissiveness, anxiousness, separation insecurity) personality disorder describe stereotypic feminine traits, unsurprisingly much more prevalent in women than in men. These categories will probably not appear in DSM-V. Antisocial personality disorder, far more common in men than in women, and consisting of manipulativeness, deceitfulness, callousness, hostility, irresponsibility, impulsivity and risk taking will probably stay as a personality disorder category in DSM-V. Borderline personality disorder, very much associated with being female, may undergo a name change in
1244
11. MENTAL DISORDERS
DSM-V and may even become an Axis-1 or clinical disorder, in which case it will have a chapter of its own in the next edition of this book. The other psychiatric diagnoses not addressed here are the paraphilias such as exhibitionistic disorder, fetischistic disorder, pedohebephilic disorder, all substantially more prevalent in men than in women. It is important to note that young boys are more often brought to psychiatric consultation than are girls but that, after puberty, a change occurs and the rate of mood, anxiety, and eating disorders escalates in women. Addictive disorders, impulse control disorders, and schizophrenia continue, in adulthood, to be more prevalent in men, but, as chapters in this section illustrate, gender leaves its imprint on these disorders as well. Is the change in gender ratios that occurs at puberty linked with a help-seeking tendency in adult women? Women seek help not only for themselves, but for their young children male and female, and even for their grown up sons when these sons fail to take the initiative. Community surveys may, it is thought, uncover more distress in women because they are less reluctant to report symptoms to interviewers than are men. For reasons of upbringing, it may be less stigmatizing for women to own up to psychological symptoms. Please see the chapter by Kessler and Gaderman1 for a fuller discussion of these issues. Uncertainty remains because, in most surveys, interviewers tend to be women, and confiding may be easier when one is speaking to a member of one’s own sex. Another possibility is that women are more likely to ‘yea-say’ than are men, more likely to confirm the presence of a specific symptom when the question is posed in an attempt to not disappoint the questioner. Women may be more likely than men to endorse what they consider to be socially and culturally acceptable (low spirits, rumination) and to deny the socially undesirable (violent impulses, drinking behavior, hallucinations). Time frames may also influence gender responsiveness, men hypothetically living more in the present than women and, therefore, remembering only current symptoms, forgetting or reinterpreting experiences from the past, even the relatively recent past. It has also been argued that items on most surveys are geared more to women’s problems (body sensations) than to men’s problems (cognitive issues). As pointed out in the Eating Disorders chapter,2 diagnostic criteria for Bulimia Nervosa (BN), for instance, rely on purging behavior whereas men are more likely to attempt weight loss through exercise rather than purging and, thus, may be less likely to receive a formal BN diagnosis. An important determinant of response to questionnaires, of course, is self-awareness. Again,
INTRODUCTION
for reasons of upbringing (child rearing being the vehicle through which social pressures are communicated to offspring), and perhaps of hormones, women are generally more aware of their internal sensations than men and better able to translate them into a psychological vocabulary. Because of care-taking responsibilities, women may also hold a higher ideal of health than men do and may consequently find their own level of health wanting. There is, however, no real evidence within any of these conjectures as to why the sex prevalence of mental health symptoms appears to change dramatically mid-puberty. Kessler and Gadermann suggest a textured interpretation, allowing for sex-role related differences in cognitive styles as well as a differential risk of stress exposure, both of which factors interact with biological givens during adolescence. Empirically-based research needs to re-examine clinical presentations and continually revise prevalence estimates so that they accurately reflect gender differences. Culture, class, occupation, and age interact with sex in complex ways to produce differing rates of illness. Is it possible that collective and conflicting social expectations (to be attractive and nurturant, to be agreeable and autonomous, to be socially interactive and competitive) impact so much on women that they alone explain some of the differential sex prevalence in depression and anxiety? Peer expectations are among the most powerful shapers of ideology and behavior and they do appear to influence, for instance, the gender prevalence of eating disorders2 or of compulsive buying 3. If expectations play an important role, socioeconomic class, ethnicity, and locale should markedly influence prevalence rates, and sometimes they do. At other times, cultural diversity is not sufficiently understood or appropriately assessed. Biology, of course, contributes to social expectations. In general, men after puberty are taller and stronger than their female same-age peers. After puberty, lipid stores in women’s bodies increase; women’s bodies become round and girls begin to develop breasts. They begin to menstruate, a preparation for reproduction. As adults, they carry each fetus for nine months prior to labor and delivery; they give birth and they nurse their infants. The lengthy proximity with their young, as well as powerful hormonal secretions, create unique bonds between mother and child. From an evolutionary viewpoint, with respect to the biological imperative of ensuring the survival of one’s DNA, males and females in most species use different behavioral strategies. Females know that the relatively few offspring they bear have all inherited their genetic material and, thus, mothers have a selfish interest in ensuring that all their infants survive. They want, therefore, to do all
11. MENTAL DISORDERS
they can to ensure the continuing loyalty of potentially faithless male partners so that they will continue to shelter and protect the children. Mothers do this is every way they can helplessness (sometimes manifesting as depression/anxiety) being a trait that is often useful. Nurturing skills also help, both in binding the male in a permanent way and in ensuring the survival of children. Males, on the other hand, can potentially sire many children, but are never absolutely certain of parentage. They would, therefore, need to evolve different selfish strategies. It can be argued that the male’s best bet is to attract partners who appear to be healthy enough to weather repeated pregnancy and childbirth, and to impregnate these partners as frequently as possible. Moreover, just in case, the male may be wise to impregnate other females as well, to increase the chances of survival of his own selfish genes. In the light of selection pressures, with males obligated to be on continuous courtship alert, impulsive/aggressive traits have survival value. Males may also benefit from an inbuilt tolerance for mind numbing substances to help them overcome social and sexual inhibitions. Like any grand theory, evolutionary theory can explain essentially all behaviour and couch it in the language of biological imperativeness. We do not have experimental data in humans, however, to support any of these speculations. Hormones undoubtedly play an important role in the sex ratios of illness. It is critical to know more about what happens in the brains of men and women at the time of puberty, since this is the period when sex ratios dramatically alter. Primate and human data suggest that certain neurons (not all) undergo active growth and/or pruning during this stage, and that the pace of these events and their final steady state are influenced by the action of pubertal hormones. In women, the cyclic monthly withdrawal of hormones may begin to interfere with one of the natural functions of estrogen; that is, its ability to neutralize the effects of glucocorticoids released in response to stress thus, perhaps, rendering women more vulnerable than men to stress hormones and, consequently, to depression and anxiety. Why are boys more vulnerable at early ages? Temperament and psychosocial risk are important to the expression of illness4. Development is also a factor. Perhaps boys are vulnerable because male brains develop slowly relative to female brains so that, at birth, they are relatively less mature. There is also a difference in lateralization, with the two hemispheres in girls being more symmetrical. The process of maturation is completed faster in girls than it is in boys, both with respect to progressive myelination and volumetric increases. Boys’ hemispheric functions are, early
INTRODUCTION
1245
on, more specialized than those of girls. In light of the above, it is possible that stressors impairing specific brain circuitry in early years have more severe impact on boys, with girls being protected by the presence of a second similarly endowed brain hemisphere and with fully formed myelin sheaths protecting their neurons. But with a comparatively longer time for reparation (via pruning of unwanted synapses and connections), boys may emerge from adolescence with lesser vulnerability to repeated stress than girls. Women’s stronger interhemispheric connections may generalize past stressors and invoke past memories with a concomitant release of stress hormones and resultant symptoms of depression and anxiety. This is, of course, speculation. With respect to pharmacological response, one important difference between males and females is that women’s bodies contain far more adipose tissue than men’s bodies per unit of body weight. Since antipsychotic drugs, antidepressants, and anxiolytics are lipophilic (bind to fat molecules), they will be retained longer in women’s bodies after drug discontinuation; they can also be released unexpectedly from fat stores during rapid weight loss, causing untoward sideeffects. Blood flow to the brain (taking the drugs along with it) is under hormonal control. It is somewhat more rapid in women than in men, which means that psychotropic agents reach their targets faster. There are also sex differences in the activity of some liver enzymes that degrade drugs prior to their elimination from the body. Alcohol, for instance, is much less efficiently detoxified by the female liver than by the male liver, so that the same initial concentration of blood alcohol is more toxic for women than it is for men. Women, in general, take a larger number of different drugs than men; drug interactions are, therefore, more frequent in women and, correspondingly, so are adverse drug reactions. In addition, specific side-effects may have more meaning for one sex than the other. Appearance being of importance to most women, drugs that detract from beauty (that put on weight, cause skin rash or hair loss) tend to reduce adherence in women. Sedating drugs that interfere with child care may do the same, while drugs that impair sexual function may pose special problems for men. Family contexts are perceived and experienced differently by men and women. There is a rich and complex literature in this area. Boys appear to be more sensitive than girls to early family upheavals such as death and divorce. In adolescence, boys perceive their families as more demanding and less supportive than do girls. Married men are better protected against psychiatric disease than single men; the opposite is true for women. Women suffer more than men from
1246
11. MENTAL DISORDERS
domestic abuse. Women are the caretakers of children and of elderly parents; the emotional burdens of family life fall more severely on their shoulders. The chapter by Kulkarni and Gavrilidis5 explores this issue in depth. All in all, however, women and men are more alike than not. The overlap between cognitive traits that are considered most divergent (such as visuo-spatial memory, for instance) is considerable. The range of differences within each sex is certainly larger than mean differences between the sexes. Nevertheless, such differences as do exist may offer clues to the origin and perpetuation of certain psychiatric diseases and, for
INTRODUCTION
that reason, it is important to identify them and to investigate them.
References [1] Kessler RC, Gadermann AM. Gender and mood disorders. This volume. [2] Bulik CM, Trace SE, Mazzeo SE. Eating disorders. This volume. [3] Sophia EC, Zilberman ML. Addictive disorders. This volume. [4] Merikangas KR, Burstein M, Schmitz A. Anxiety disorders in women. This volume. [5] Kulkarni J, Gavrilidis E. Psychosis in women: Gender differences in presentation, onset, course, and outcome of schizophrenia. This volume.
11
MENTAL DISORDERS INTRODUCTION Mary V. Seeman INTRODUCTION Men and women differ in the prevalence and severity of mental illnesses that they suffer from. This opinion needs to be stated with caution because the diagnosis of a specific mental illness is primarily based on symptoms reported by the patient. More or less ‘neutral’ parties such as clinicians and family members add their observations, but ‘harder’ evidence from biopsies, blood tests, or diagnostic brain changes are rarely available to distinguish among categories of psychiatric illness. To complicate things further, there is considerable overlap in symptoms among differently named illnesses, and overlap also exists between what we determine to be illness and what we consider to be within the range of health. The divisions between wellness and illness, and among psychiatric illnesses, can be relatively arbitrary. Because symptoms fluctuate, they are unreliable anchors. Because some individuals are readier to disclose symptoms than others or more disposed to seek help for them, there may be many, equally ill, who are not identified. For many DSM-IV diagnoses, symptoms alone are not sufficient to identify someone as ill; an impairment in function must also exist. That can be problematic since adequate functioning depends on many factors besides the severity of an illness, e.g. socioeconomic status, intelligence, personality traits, family support or social role within the family or community. For all these reasons, although male/female differences in the prevalence of many psychiatric disorders appear to exist, it is probably premature to state unequivocally that they do. If we suspend disbelief, however, and assume that sex differences are a fact, such differences can provide clues to etiology. We can then search for effects of exposure to distinct environments,
hormonal effects, gene dosage effects, genetic imprinting effects or microchimerism (the passage of antigens across the placenta during pregnancy). Most likely, sex differences in disease will prove to be based on combinations of the above. We no longer speak of the differential effects of nature versus nurture, since the two are one: vulnerabilities in our DNA can be overcome or exaggerated by what we experience. The chapters in this section focus on mood disorders, schizophrenia, post-traumatic disorders, eating disorders, and addictive disorders. Alzheimer’s disease is covered elsewhere in this volume, in the section on aging. Social and reproductive contributions to women’s health are also addressed in other sections. Not addressed are dissociative disorders such as dissociative amnesia, or dissociative identity disorder, both more common in women than in men although the diagnostic category is controversial; the DSM-V workgroup is reconsidering it. Classification of personality disorders is also being reconsidered and these disorders are likewise not addressed in this section. Personality disorders as a group refer to stable, significant impairments in interpersonal functioning. The DSM-IV categories of histrionic (emotional lability, manipulativeness, attention seeking) and dependent (submissiveness, anxiousness, separation insecurity) personality disorder describe stereotypic feminine traits, unsurprisingly much more prevalent in women than in men. These categories will probably not appear in DSM-V. Antisocial personality disorder, far more common in men than in women, and consisting of manipulativeness, deceitfulness, callousness, hostility, irresponsibility, impulsivity and risk taking will probably stay as a personality disorder category in DSM-V. Borderline personality disorder, very much associated with being female, may undergo a name change in
1244
11. MENTAL DISORDERS
DSM-V and may even become an Axis-1 or clinical disorder, in which case it will have a chapter of its own in the next edition of this book. The other psychiatric diagnoses not addressed here are the paraphilias such as exhibitionistic disorder, fetischistic disorder, pedohebephilic disorder, all substantially more prevalent in men than in women. It is important to note that young boys are more often brought to psychiatric consultation than are girls but that, after puberty, a change occurs and the rate of mood, anxiety, and eating disorders escalates in women. Addictive disorders, impulse control disorders, and schizophrenia continue, in adulthood, to be more prevalent in men, but, as chapters in this section illustrate, gender leaves its imprint on these disorders as well. Is the change in gender ratios that occurs at puberty linked with a help-seeking tendency in adult women? Women seek help not only for themselves, but for their young children male and female, and even for their grown up sons when these sons fail to take the initiative. Community surveys may, it is thought, uncover more distress in women because they are less reluctant to report symptoms to interviewers than are men. For reasons of upbringing, it may be less stigmatizing for women to own up to psychological symptoms. Please see the chapter by Kessler and Gaderman1 for a fuller discussion of these issues. Uncertainty remains because, in most surveys, interviewers tend to be women, and confiding may be easier when one is speaking to a member of one’s own sex. Another possibility is that women are more likely to ‘yea-say’ than are men, more likely to confirm the presence of a specific symptom when the question is posed in an attempt to not disappoint the questioner. Women may be more likely than men to endorse what they consider to be socially and culturally acceptable (low spirits, rumination) and to deny the socially undesirable (violent impulses, drinking behavior, hallucinations). Time frames may also influence gender responsiveness, men hypothetically living more in the present than women and, therefore, remembering only current symptoms, forgetting or reinterpreting experiences from the past, even the relatively recent past. It has also been argued that items on most surveys are geared more to women’s problems (body sensations) than to men’s problems (cognitive issues). As pointed out in the Eating Disorders chapter,2 diagnostic criteria for Bulimia Nervosa (BN), for instance, rely on purging behavior whereas men are more likely to attempt weight loss through exercise rather than purging and, thus, may be less likely to receive a formal BN diagnosis. An important determinant of response to questionnaires, of course, is self-awareness. Again,
INTRODUCTION
for reasons of upbringing (child rearing being the vehicle through which social pressures are communicated to offspring), and perhaps of hormones, women are generally more aware of their internal sensations than men and better able to translate them into a psychological vocabulary. Because of care-taking responsibilities, women may also hold a higher ideal of health than men do and may consequently find their own level of health wanting. There is, however, no real evidence within any of these conjectures as to why the sex prevalence of mental health symptoms appears to change dramatically mid-puberty. Kessler and Gadermann suggest a textured interpretation, allowing for sex-role related differences in cognitive styles as well as a differential risk of stress exposure, both of which factors interact with biological givens during adolescence. Empirically-based research needs to re-examine clinical presentations and continually revise prevalence estimates so that they accurately reflect gender differences. Culture, class, occupation, and age interact with sex in complex ways to produce differing rates of illness. Is it possible that collective and conflicting social expectations (to be attractive and nurturant, to be agreeable and autonomous, to be socially interactive and competitive) impact so much on women that they alone explain some of the differential sex prevalence in depression and anxiety? Peer expectations are among the most powerful shapers of ideology and behavior and they do appear to influence, for instance, the gender prevalence of eating disorders2 or of compulsive buying 3. If expectations play an important role, socioeconomic class, ethnicity, and locale should markedly influence prevalence rates, and sometimes they do. At other times, cultural diversity is not sufficiently understood or appropriately assessed. Biology, of course, contributes to social expectations. In general, men after puberty are taller and stronger than their female same-age peers. After puberty, lipid stores in women’s bodies increase; women’s bodies become round and girls begin to develop breasts. They begin to menstruate, a preparation for reproduction. As adults, they carry each fetus for nine months prior to labor and delivery; they give birth and they nurse their infants. The lengthy proximity with their young, as well as powerful hormonal secretions, create unique bonds between mother and child. From an evolutionary viewpoint, with respect to the biological imperative of ensuring the survival of one’s DNA, males and females in most species use different behavioral strategies. Females know that the relatively few offspring they bear have all inherited their genetic material and, thus, mothers have a selfish interest in ensuring that all their infants survive. They want, therefore, to do all
11. MENTAL DISORDERS
they can to ensure the continuing loyalty of potentially faithless male partners so that they will continue to shelter and protect the children. Mothers do this is every way they can helplessness (sometimes manifesting as depression/anxiety) being a trait that is often useful. Nurturing skills also help, both in binding the male in a permanent way and in ensuring the survival of children. Males, on the other hand, can potentially sire many children, but are never absolutely certain of parentage. They would, therefore, need to evolve different selfish strategies. It can be argued that the male’s best bet is to attract partners who appear to be healthy enough to weather repeated pregnancy and childbirth, and to impregnate these partners as frequently as possible. Moreover, just in case, the male may be wise to impregnate other females as well, to increase the chances of survival of his own selfish genes. In the light of selection pressures, with males obligated to be on continuous courtship alert, impulsive/aggressive traits have survival value. Males may also benefit from an inbuilt tolerance for mind numbing substances to help them overcome social and sexual inhibitions. Like any grand theory, evolutionary theory can explain essentially all behaviour and couch it in the language of biological imperativeness. We do not have experimental data in humans, however, to support any of these speculations. Hormones undoubtedly play an important role in the sex ratios of illness. It is critical to know more about what happens in the brains of men and women at the time of puberty, since this is the period when sex ratios dramatically alter. Primate and human data suggest that certain neurons (not all) undergo active growth and/or pruning during this stage, and that the pace of these events and their final steady state are influenced by the action of pubertal hormones. In women, the cyclic monthly withdrawal of hormones may begin to interfere with one of the natural functions of estrogen; that is, its ability to neutralize the effects of glucocorticoids released in response to stress thus, perhaps, rendering women more vulnerable than men to stress hormones and, consequently, to depression and anxiety. Why are boys more vulnerable at early ages? Temperament and psychosocial risk are important to the expression of illness4. Development is also a factor. Perhaps boys are vulnerable because male brains develop slowly relative to female brains so that, at birth, they are relatively less mature. There is also a difference in lateralization, with the two hemispheres in girls being more symmetrical. The process of maturation is completed faster in girls than it is in boys, both with respect to progressive myelination and volumetric increases. Boys’ hemispheric functions are, early
INTRODUCTION
1245
on, more specialized than those of girls. In light of the above, it is possible that stressors impairing specific brain circuitry in early years have more severe impact on boys, with girls being protected by the presence of a second similarly endowed brain hemisphere and with fully formed myelin sheaths protecting their neurons. But with a comparatively longer time for reparation (via pruning of unwanted synapses and connections), boys may emerge from adolescence with lesser vulnerability to repeated stress than girls. Women’s stronger interhemispheric connections may generalize past stressors and invoke past memories with a concomitant release of stress hormones and resultant symptoms of depression and anxiety. This is, of course, speculation. With respect to pharmacological response, one important difference between males and females is that women’s bodies contain far more adipose tissue than men’s bodies per unit of body weight. Since antipsychotic drugs, antidepressants, and anxiolytics are lipophilic (bind to fat molecules), they will be retained longer in women’s bodies after drug discontinuation; they can also be released unexpectedly from fat stores during rapid weight loss, causing untoward sideeffects. Blood flow to the brain (taking the drugs along with it) is under hormonal control. It is somewhat more rapid in women than in men, which means that psychotropic agents reach their targets faster. There are also sex differences in the activity of some liver enzymes that degrade drugs prior to their elimination from the body. Alcohol, for instance, is much less efficiently detoxified by the female liver than by the male liver, so that the same initial concentration of blood alcohol is more toxic for women than it is for men. Women, in general, take a larger number of different drugs than men; drug interactions are, therefore, more frequent in women and, correspondingly, so are adverse drug reactions. In addition, specific side-effects may have more meaning for one sex than the other. Appearance being of importance to most women, drugs that detract from beauty (that put on weight, cause skin rash or hair loss) tend to reduce adherence in women. Sedating drugs that interfere with child care may do the same, while drugs that impair sexual function may pose special problems for men. Family contexts are perceived and experienced differently by men and women. There is a rich and complex literature in this area. Boys appear to be more sensitive than girls to early family upheavals such as death and divorce. In adolescence, boys perceive their families as more demanding and less supportive than do girls. Married men are better protected against psychiatric disease than single men; the opposite is true for women. Women suffer more than men from
1246
11. MENTAL DISORDERS
domestic abuse. Women are the caretakers of children and of elderly parents; the emotional burdens of family life fall more severely on their shoulders. The chapter by Kulkarni and Gavrilidis5 explores this issue in depth. All in all, however, women and men are more alike than not. The overlap between cognitive traits that are considered most divergent (such as visuo-spatial memory, for instance) is considerable. The range of differences within each sex is certainly larger than mean differences between the sexes. Nevertheless, such differences as do exist may offer clues to the origin and perpetuation of certain psychiatric diseases and, for
INTRODUCTION
that reason, it is important to identify them and to investigate them.
References [1] Kessler RC, Gadermann AM. Gender and mood disorders. This volume. [2] Bulik CM, Trace SE, Mazzeo SE. Eating disorders. This volume. [3] Sophia EC, Zilberman ML. Addictive disorders. This volume. [4] Merikangas KR, Burstein M, Schmitz A. Anxiety disorders in women. This volume. [5] Kulkarni J, Gavrilidis E. Psychosis in women: Gender differences in presentation, onset, course, and outcome of schizophrenia. This volume.