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Gender and age differences in the prevalence of specific fears and phobias
~
Pergamon
Behav. Res. Ther. Vol. 34, No. 1, pp. 33-39, 1996
0005-7967(95)00048-8
Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0005-7967/96 $9.50 + 0.00
Gender and age differences in the prevalence of specific fears and phobias M A T S F R E D R I K S O N 1'2., P E T E R A N N A S l, H / ~ K A N F I S C H E R j a n d G U S T A V W I K 3
~Department of Clinical Neuroscience, Karolinska Institute and Hospital, Sweden, 2Department of Clinical Psychology, Uppsala University, Box 1225, S-751 42 Uppsala, Sweden and 31nstitut fiir Experimentelle Audiologie, Westfiilische Wilhelmsuniversitgit, Miinster, Germany (Received 25 April 1995) Summary--Point prevalence of specific fears and phobias was determined in 704 respondents of 1000 randomly selected adults aged 18 70yr. A phobia for lightning, enclosed spaces, darkness, flying, heights, spiders, snakes, injections, dentists and/or injuries was defined if subjects reported a fear that was out of conscious control, interfered with life and lead to the avoidance of the feared object [American Psychiatric Association, 1994. Diagnostic and statistical manual of mental disorders (4th edn). Washington, DC: American Psychiatric Press.] Fear intensity was assessed using visual analogue scales. A factor analysis generally supported the classification of fears and phobias into: (1) situational phobias (lightning, enclosed spaces, darkness, flying and heights); (2) animal phobias (spiders and snakes); and (3) mutilation phobias (injections, dentists, injuries). Total point prevalence of any specific phobia was 19.9% (26.5% for females and 12.4% for males). In total, 21.2% women and 10.9% men met criterias for any single specific phobia. Multiple phobias was reported by 5.4% of the females and 1.5% of the males. Animal phobia had a prevalence of 12.1% in women and 3.3% in men. Point prevalence of situational phobia was 17.4% in women and 8.5% in men. For mutilation phobia no gender difference was observed, being presented in 3.2% of the women and 2.7% of the men. Women as compared to men gave higher fear ratings for all objects and situations. Inanimate object fears and phobias were more common in older than younger individuals. Animal fears were more intense in younger than in older individuals. Fear of flying increased and fear of injections decreased as a function of age in women but not in men. Thus, specific fears and phobias are heterogeneous with respect to sex and age distribution.
INTRODUCTION Phobias are defined as unreasonable fears, associated with the avoidance of objects or situations, that interferes with life (DSM IV, American Psychiatric Association, 1994). Phobias are categorized as specific, social or agoraphobias (DSM IV). At least 14 studies (see Table 1) have presented prevalence rates for different types of phobias. In the first epidemiological study performed when DSM (1952) defining criterias were used Agras, Sylvester and Oliveau (1969) reported a 6.3% point prevalence estimate of any specific and a 7.7% estimate of any phobia in a combined sample of men and women. Costello (1982) reported a 12-month prevalence rate of specific phobia in women varying between 4.9 and 12.5%, depending on the phobias that were included. A phobia was in that study defined as intense fear associated with the avoidance of a specific object. In the Epidemiological Catchment Area (ECA) surveys (Robins, Helzer, Weissman, Orvaschel, Gruenberg, Burke & Regier, 1984; Myers, Weissman, Tischler, Holzer, Leaf, Orvaschel, Anthony, Boyd, Burke, Kramer & Stoltzman, 1984; Regier, Boyd, Burke, Rae, Myers, Kramer, Robins, George, Karno & Locke, 1988; Boyd, Rae, Thompson, Burns, Bourdon, Locke & Regier, 1990), DSM-III-R (American Psychiatric Association, 1987) criteria were used to define phobia and prevalence rates of specific phobias varied from 2 to 26%. Part of the variation was due to location,, sex and time. The variation between cities could not be accounted for except that Myers et al. 0984) suggested that different wording related to prevalence differences. Wittchen (1986) used DSM-III criteria and observed a 6-month prevalence of 4.1% and a lifetime prevalence of 8% for specific phobia in men and women (Table 1). Kendler, Neale, Kessler, Heath & Eaves (1992) studying mono- and dizygotic twins reported a 20.5% lifetime prevalence of any DSM-III-R defined specific phobia including animal (insects, spiders, mice, snakes and bats) or situational (tunnels, other closed places, bridges, airplanes, other high places) phobias. Kessler, McGonagle, Zhao, Nelson, Hughes, Eshleman, Wittchen and Kendler (1994) recently presented results from the national comorbidity survey in the United States and reported a life-time prevalence of specific phobia of 6.7% in men and 15.7% in women. Part of the variation in prevalence is most likely due to the fact that in some but not other studies a decrease in the global assessment of functioning has been part of the phobia definition. Most studies treat the more circumscribed specific phobias separate from the less circumscribed social phobia and agoraphobia. However, studies mainly treat specific phobia as a single entity. Because specific phobias seem heterogeneous with respect to age at onset (Ost, 1987), genotype (Kendler et al., 1992; Rose, Miller, Pogue-Geile & Cardwell, 1981) and possibly evolutionary underpinnings (Seligman, 1971) there could be reasons to study the epidemiology of specific fears and phobias for different objects and situations separately. Rosenhan and Seligman (I 989), suggested that specific phobias could be grouped into three categories, namely: situational phobias, animal phobias and mutilation phobias. In the present study phobias of snakes and spiders was classified as "animal phobia". Phobia of lightning, enclosed spaces, darkness, flying and heights was classified as "situational phobia" *To whom all correspondence should be addressed at: Department of Clinical Psychology, Uppsala University, Box 1225, S-751 42 Uppsala, Sweden. 33
interview schedule DSMs
one-point 325
interview
1645
6-month more than 9000 18 and over DISc DSMillh
one-point 449 18~5 PSEd
intensity+
5.0-12.5% Calgary
2.3-7.3% 6.0-15.7% 3 ECAb cities
10.2-30.0%t
Florida
0.9-1.7% 1.5-2.6%
10.6%t
2.~8.6% 7.7-17.5% 0.9-3A% 4.2-7.8%
19.0% 2.9% 8.3%
DSMIll
lifetime 9543 18 and over DIS DSMIII
lifetime 657 2~63 DIS
3.8-14.5% 5.5% 8.5-25.9% 10.4% 3 ECA cities Munich
1.5-5.2% 5.3-12.5% 2,4% 3.2%
DSMIII
6-month 3648 18 and over DIS DSMIIIRi
ASIf
one-point 500
DSMIIIR
lifetime 18 572 18 and over DIS
7.2% 13.9%** 5 ECA cities
2.3% 3.2%
2.9% 7~7%**
9.2% 17.0%**
DSMIIIR
lifetime 1498 16~4 DIS
CPEc
5.9%t
3.9%t
0.36%
6.8% 14.6%
Pollard & Bourden e t al, Joyce e t al. Henderson 1987 1988 1989
9.5%-7.9% a 13.2%-16.6%* North Carolina St. Louis
1.7%-2.6% 2.5%-3.6% a
2.2%-4,6%* 6A%-7.9% t
Robins e t al. Wittchen George e t o,l. 1984 1986 1986
Table I. Prevalence a n d gender differences in phobias in different epidemiological studies Myers e t al, 1984
I 1.3%t
15.5%t
Costello 1982
structured interview DSMIIIR
lifetime 1110
0.09% 0.54% Florence
0.72% 0.27%
0.90%
DSMIIlR
1-month 18 571 18 and over DIS
5 ECA cities
5.1%t
1.3%t
2-9%t
6.2%t
Faravelli et al, Boyd e l al. 1989 1990
DSMIIIR
DIS
20.2% Virginia Twin registry Lifetime 2163
11.5%
8.7%
33.4%
Kendler e t al. 1992
DSMIV
one-point 704 18-70 questionnaire
12.4% 26.5%*" Stockholm
The present study
*P < 0.05 (reported P-value); **P < 0.01 (reported P-value); "['total prevalence. aRural-Urban; bEpidemiotogicat Catchment Area program; CChristchurch Psychiatric Epidemiology; dPrescnt State Examinations; ~Diagnostic Interview Schedule; rAnxiety Symptoms Interview; SDiagnostic and Statistic Manual o f mental disorders, 1952; hDiagnostic and Statistic M a n u a l o f mental disorders, 1980; ~Diagnostic and Statistic M a n u a l o f mental disorders, 3rd edition 1987.
Period of prevalence Sum of subjects Age of subjects Data collecting method Phobia definition
Men 7.7%t Women Agoraphobia + panic Men Women Social phobia Men Women Simple phobia Men Women Place Burlington
Any phobia
Agras el a/, Schwab e t al. 1969 1979
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and phobia of injections, dentists and injurys as "mutilation phobia". These situations and objects were chosen because they commonly elicit fear and phobia (of. Agras et al., 1969; Rosenhan & Seligman, 1989). Women generally display more phobias than men (Marks, 1969; Lindal & Stef~nsson, 1993). Furthermore, it has been reported (cf. Marks, 1969) that sex differences in specific phobias are present predominantly after puberty. However, it has only seldom been determined whether sex differences in specific fears and phobia prevail, increase or decrease throughout the adult lifecycle. Agras et al. (1969) reported lower fear ratings with increasing age but did not include estimates of phobias. The aim of the present study was to determine prevalence rates of phobias for lightning, enclosed spaces, darkness, flying, heights, spiders, snakes, injections, dentists and injuries in younger and older women and men. Point prevalence was chosen over other estimates since it has been argued that recall over more extended time periods might pose reliability problems (Burvill, 1987; Parker, 1987). Presence of phobia was determined using true/false questions based on DSM-IV criteria. Fear intensity was rated using visual analogue scales. Finally, by performing a factor analysis we studied if the three factor structure for specific fears and phobias, as suggested by Rosenhan & Seligman (1989), could obtain empirical support. METHOD Subjects Five hundred male and 500 female Ss from the greater Stockholm area, aged 18--70 yr, were randomly selected from a population-based registry (L-data). A questionnaire was mailed together with a stamped return envelope. Within 3 weeks, 242 men and 274 women had replied. After a reminding letter was sent out, 336 men and 384 women, a total number of 720 Ss, had returned the questionnaires. Five men and 11 women replied in ways impossible to interpret and were excluded. Thus, a total of 704 Ss were eligible for analyses. Questionnaires Questions on fear of snakes, spiders, lightning, enclosed spaces, darkness, flying, heights, injections, dentists and injuries were included. Based on DSM-IV criteria, the following true-false questions were used to define a phobia: (1) I give up things because of my fear; (2) My fear is greater than justified; (3) I cannot control my fear. If Ss answered all 3 questions in the affirmative, a phobia was defined for each object and/or situation. Subjects were classified as having no, single or multiple phobias. Subjects also completed visual analogue scale (VAS) ratings of fear for snakes, spiders, lightning, enclosed spaces, darkness, flying, heights, injections, dentists, injuries. Zero denoted "no fear at all" and 100 "maximal fear". Statistical methods Statistical tests included analyses of variance, factor analyses and chi-square tests. Data were analyzed using the Statistical Package for Social Sciences; Macintosh version 4.0. Means and confidence intervals are presented in order to increase comparability with other studies. RESULTS The mean ( + S D ) age was 41.5 yr (_+ 14.2) and 41.4 yr ( _ 14.0) for women and men respectively. To define relatively younger and older S s, a median (Md = 41.0) split approach resulted in an average ( + SD) age of 29.0 yr (6.5) in the younger and of 53.3 yr (+8.4) in the older group. Fears The factor structure obtained from factor analyses of VAS ratings resulted in three separate dimensions and generally supported the theoretically based structure of Rosenham and Seligman (1989), (see Table 2). To be included in a factor the item had to display a factor loading greater than 0.50. The injury item did not meet the criteria for the mutilation factor but displayed a 0.44 loading. However, the injury item had its highest loading in the mutilation factor and therefore was included in this factor. Table 3 gives visual analogue scale ratings of fear for each item and groups of items in younger and older men and women. Women reported significantly more intense fear than men for all separate items and groups of items (see Table 3). Fear ratings of animals, particularly of spiders, were higher in younger than older individuals. Lower fear ratings of lightning, heights and flying in younger than older Ss resulted in lower average situational fear intensity. Fear of injections was higher in the young (see Table 3). Two significant interactions between gender and age for fear intensity pertained to higher fear of flying and lower fear of injections in older than younger women, whereas ratings were similar in older and younger men. No other interactions reached significance. For fear of flying, younger women gave a rating of 18.4 and older of 27.1
Table 2. The factor structure of fears as determined by varimax rotation analysis Items Lightning Closed spaces Darkness Heights Flying Snake Spider Injections Dentist Injuries
Factor 1 (Situational fears)
Factor II (Animal fears)
Factor Ill (Mutilation fears)
0.64 0.69 0.50 0.67 0.75 ---
-----0.74 0.83
--------
----
----
0.84 0.75 0.44
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Table 3. Average (_+SD) visual analogue scale ratings of fear and confidence intervals (Cls) in men and women as well as young and old individuals as defined by a median split approach. Gender and age differences are tested by analysis of variance
Average animal fear Snakes Spiders
Cls
17.6 (18.1) 22.3 (24.4) 12.9 (19.0)
15.6-19,7 19.6-25.1 10.8-15.1
32.6 (25.5) 38.1 (31.5) 27.2 (29.6)
15.9-19.6 6.2-9.4 18.7-24.9 10.6-14.8 29.1-35.7 11.1-16.2
31.5 25.1 37.6 29.0 43.3 22.7
17.5 (24.9) 17.9 (25.9) 23.4 (24.8)
17.5-21.8 14.7-20.3 15.0-21.0 20.6-26.2
25.9 21.7 23.6 32.4
Younger
CIs
28.1 (24.0) 31.0 (29.0) 25.2 (28.7)
25.5-30.8 27.8-34.2 22.0-28.4
23.5 (23.0) 31.0 (29.9) 16.2 (22.6)
21.1-26.0 27.7-34.2 13.8-18.6
F(1,651) = 6.3** F(1,651) < 1 F(1,653) = 19.8"**
20.9-25.0 10.6-15.3 25.0-31.8 18.9-24.5 31.5-38.5 13.3-18.7
27.0 20.7 31.8 21.0 41.1 20.7
24.8-29.2 17.8-23.5 28.5-35.2 18.4-23.7 37.7~4.5 17.8-23.6
F(1,649) = F(I,651) = F(1,652) = F(1,654) < F(1,653) = F(1,652) =
7.0** 16.3"** 1.9 1 6.1"* 5.5*
21.6-26.2 19.9-26.1 18.7-24.9 23.6-29.6
22.2 (19.8) 16.9 (23.4) 20.4 (25.4) 29.9 (28.2)
20.1-24.4 14.4-19.4 17.7-23.1 26.8-32.9
F(l,651) F(1,653) F(1,652) F(1,654)
1.1 9.0** 1 2.2
Average situational fear 17.7 (16.1) Lightning 7.8 (14.3) Closed spaces 21.8 (28.0) Darkness 12.7 (18.4) Heights 32.4 (29.7) Flying 13.7 (22.6)
Average mutilation fear 19.6 (19.6) Injections Dentists Injuries
Average animal fear Snakes Spiders
Average situational fear 23.0 (18.2) Lightning 12.9 (21.2) Closed spaces 28,4 (30.7) Darkness 21.7 (25.1) Heights 35,0 (31.6) Flying 16,0 (24.2)
Average mutilation fear 23.9 (20.9) Injections Dentists Injuries
Gender differences Women Cls
Men
23,0 (28.4) 21.8 (27.7) 26.6 (27.2)
Total
CIs
30.0-35.3 34.8--41.4 24.1-30.3
25.6 (23.5) 30.7 (29.4) 20.6 (26.1)
23.8-27.4 28.5-33.0 18.6-22.5
F(I,657) = 73.9*** F(1,657) =50.8*** F(1,659) = 53.1"**
(20.3) (28.7) (31.9) (27.6) (33.3) (27.6)
29.4--33.7 22.0--28.1 34.2-40.9 26.1-31.9 39.8-46.7 19.8-25.6
25.0 (19.7) 17.0 (24.6) 30.1 (31.1) 21.4 (25.1) 38.2 (31.9) 18.4 (25.7)
23.6-26.6 15.1-18.8 27.8-32.5 19.5-23.3 35.8-40.6 16.5-20.4
F(1,655) =91.0"** F:1,657) = 91.5"** F(I,658) =45.1"** F(1,660) = 77.7*** F(1,659) = 19.7"** F(1,658) = 20.8***
(20.6) (26.9) (26.7) (29.5)
23.7-28.0 18.9-24.5 20.8-26.4 29.3-35.5
22.9 (20.3)
21.3-24.5 17.7-21.7 18.9-23.0 26.1-30.3
F(1,657) = 15.8"** F(I,659) =4.4* F(1,658) = 7.9** F(1,660) = 17.8"**
19.7 (26.0) 20.9 (26.5) 28.2 (27.7)
Age differences Older Cls
(20.7) (26.9) (31.5) (24.9) (31.8) (26.9)
Gender differences
Age differences
= = < =
*P <0.05; **P < 0.01; ***P < 0.001.
[t(162) = 2.749; P < 0.001] whereas younger and older m e n gave ratings of 12.9 and 13.9 respectively [t(162) < 1; NS]. F o r injections, VAS-ratings o f 27.6 and 15.8 were given by younger and older w o m e n [t(162) = 3.852; P < 0.001], whereas younger and older men had ratings o f 17.2 and 18.0 respectively [t(136) < 1; NS].
Phobias 19.9% of all S s met the criterias for any single or multiple specific phobia; 26.5% of all w o m e n and 12.4% of all men L~2(1) = 22.0; P < 0.01] (see Table 4). 16.3% met criterias for any m o n o s y m p t o m a t i c phobia and 3.6% met criterias for
Animsi
/
\
Mutilation
35 (5.2%)
[
~
12 {1.8%)
16 (2.3%} ~w~ 4 (0.6%) Situational 68 (10.0%)
Fig. 1. Distribution of individuals reporting animal, mutilation and situational phobias in a randomly selected cohort of 704 Ss.
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Table 4. Average (+SD) prevalence rates confidence intervals (Cls), gender and age differences of specific phobias in men and women as well as young and old individuals as defined by a median split approach. Gender and age differences are tested by chi square analysis Gender differences Women Cls %
Men %
Cls
Total %
Cls
Any animal phobia Snakes Spiders
3.3 (17.9) 2.4 (15.4) 1.2 (10.9)
1.4-5.3 0.7-4. I 0.0-2.4
12,1 ( 3 2 . 6 ) 8.3 (27.6) 5.6 (23.1)
Any situational phobia Lightning Closed spaces Darkness Heights Flying
8.5 (27.9) 0.3 ( 5 . 5 ) 2.4 (15.4) 0.0 ( 0 . 0 ) 6.3 ( 2 . 4 ) 1.8 (13.4)
5.4-11.5 0.34.9 0.7-4.1 0.0-0.0 0.4-9.0 0.4-3.3
Any mutilation phobia Injections Dentists Injuries
2.7 (16.3) 1.2 (10.9) 2.1 (14.4) 2.4 (15.4)
1.0-4.5 0.0-2.4 0.6-3.7 0.7-4.1
Younger %
CIs
Any animal phobia Snakes spiders
7.9 ( 2 . 7 ) 4.4 ( 2 . 1 ) 4.7 ( 2 . 1 )
Any situational phobia Lightning Closed spaces Darkness Heights Flying Any mutilation phobia Injections Dentist Injuries
;( 5
8.7-15.4 5.5-11.1 3.9-8.0
7.9 (27.1) 5.5 (22.9) 3.5 (18.5)
5.9-10.0 3.8-7.2 2.2-4.9
17.4 (38.0) 3.7 (19.0) 5.4 (22.6) 4.3 (20.2) 8.6 (28.0) 3.2 (17.7)
13.6-21.3 1.8-5.7 3.1-7.7 2.2-6.4 5.7-11.4 1.4-5.0
13.2 (33.9) 2.1 (14.4) 4.0 (19.6) 2.3 (14.9) 7.5 (26.4) 2.6 (15.8)
10.7-15.7 I.I-3.2 2.5-5.4 1.2-3.4 5.6-9.5 1.3-3.7
;(5(1) = ;(5(I) = ;(5(1) = ;(5(1) = ;(2(1) = Z2(I) =
12.3"* 10.0"* 4.0* 14.6"** 1.3 1.4
3.2 (17.7) 1.9 (13.6) 2.1 (14.5) 4.0 (19.7)
1.4-5.0 0.5-3.3 0.7-3.6 2.0-6.0
3,0 (17.0) 1.6 (12.4) 2,1 (14.4) 3,3 (17.8)
1.7-4.2 0.6-2.5 1.1-3.2 1.9-4.6
;(5(I) < ;(2(1) < ;(2(1) < z2(l) =
I 1 1 1.4
Z2(I) = 18.3"** j(2(1) = 11.6"* ;(2(1) = 10.0"*
Age differences Older Cls %
Z2
5.1-10.8 2.2-6.6 2.4-7.0
8.1 (2.7) 6.7 (2.5) 2.5 (I.6)
6.3-12.5 4.1-9.3 0.9-4.1
;(2(t) < 1 ;(2(1) = 1.7 Z2(I) = 2.4
9.4 ( 2 . 9 ) 0.9 (1.0) 2.6 ( 1 . 6 ) 2.1 ( 1 . 4 ) 5.3 ( 2 . 2 ) 1.8 (1.3)
6.3-12.5 0.1-1.9 0.9-4.4 0.5-3.6 2.9-7.7 0.4-3.2
16.8 ( 3 . 7 ) 3.3 (1.8) 5.3 (2.4) 2.2 (1.5) 9.9 ( 2 . 3 ) 3.3 (1.8)
12.9-20.6 0.1-5.2 3.0-7.6 0.7-3.8 6.7-12.9 1.5-5.2
;(2(1) = ;(2(1) = ;(2(1) = X2(I) < ;(2(1) = ;(2(1) =
8.2** 5.1" 3.2 1 5.0* 1.8
3.8 (I.9) 1.8 (I.3) 2.6 ( 1 . 6 ) 2.1 (1.4)
1.8-5.9 0.4-3.2 0.9-4.4 0.5-3.6
2.2 (1.5) 1.4 (1.2) 1.7 (1.3) 4.5 (2.1)
0.7-3.8 0.2-2.6 0.3-3.0 2.3-6.6
;(2(1) = ;(2(I) < Z2(I) < Zs(1) =
1.5 1 I 3.18
*P < 0.05, **P < 0.01, ***P < 0.001.
multiple phobias. There was overlap especially for situational and animal phobia, but less so for animal and mutilation phobia (see Fig. 1). Gender differences in the frequency of both monosymptomatic and multiple phobias were found. 21.2% of the female and 10.9% of the male population had a single specific phobia ~2(1) = 13,6; P < 0.01], while 5.4% of the female and 1.5% of the male population had multiple phobias [22(1) --- 7.6; P < 0.01]. Inanimate object phobia (13.2%) was the most c o m m o n phobia type followed by animal (8%) and mutilation phobia (3%). There were gender differences in animal and situational phobia but not in mutilation phobia. 17.4% of the females and 8.5% of the males had situational phobia (see Table 4). 12% of the female and 3.3% of the male sample displayed animal phobia. 3.2% of the female and 2.7% of the male sample had mutilation phobia (see Table 4). DISCUSSION Total point prevalence o f one or more specific phobia(s) was 19.9%; 26.5% for women and 12.4% for men. Roughly 16% had any specific phobia, while around 4% reported having multiple phobias. More women than men had animal and situational phobias. For mutilation phobia no gender differences were observed. A factor analysis indicated the existence of three separate and independent factors in specific phobia namely animal, situational and mutilation phobia. DSM-IV maintains that specific phobias m a y be categorized as animal type, natural environment type, blood-injection-injury type or situational type. Results from the factor analysis performed in the present study supported an animal, a blood-injection injury-mutilation and a situational phobia type. Storms and heights are given as examples of natural environment phobia in the DSM-IV. In the present study however, fears and phobias of thunderstorms and of heights clustered together with fear of enclosed places, darkness and flying. This suggests that the situational and the natural environment phobia type could share a c o m m o n underlying theme. Findings are in general agreement with previous studies reporting a higher phobia prevalence in women than men (el. Marks, 1969). This m a y reflect true differences, response bias or measurement precision problems. Confidence intervals estimate the precision o f the point estimate, and it is not obvious that measurements of mutilation phobia are less reliable than those of the other two phobia types at least not as reflected in wider confidence intervals. Therefore, variations in the precision of the measurement do not seem to account for gender differences. Sex differences were observed for animal and situational phobias but not for mutilation phobia. Data does not support that women are generally more willing to admit their phobias. Because mutilation phobias were reported equally often a m o n g the two sexes and since response bias most likely would affect reporting of all phobia types alike. This argues against response bias as an explanation of gender
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differences in phobias. Instead, women may be more vulnerable to animal and situational phobias. Gender differences may then reflect different genetic and/or environmental transmission patterns. To the best of our knowledge, no data has been reported to suggest different genetic vulnerability for phobia in men and women. However, this possibility is currently investigated in our laboratory. It is also conceivable that experiental factors differ between men and women. In experimental studies on aversive conditioning (Fredrikson, Hugdahl & Ohman, 1976) sex differences in acquisition and extinction rate were not observed. Thus, sex differences in fear-conditionability does not seem like a plausible single explanation for sex differences in phobia prevalence. It is conceivable that learning processes relevant to phobia acquisition, other than classical conditioning, could differ between the two sexes. For example, it has been suggested that the process of incubation, when fear intensity increases as a function of time, may operate in phobia acquirement (Eysenck, 1985). If traumatic experiences with, for example heights and lightning are equally common among the two sexes, data implicate that incubation should be more commonly observed in women than men. Thus data from the present study do not demonstrate but are consistent with an increased rate of socially transmitted fears and phobias in women as compared to men. Social transmission of fears and phobias might be more frequent or facilitated among women than men. Role modelling, the processes through which a fearful model transmits fear to an observer, seems to occur more frequently among women then men (Fredrikson, Annas & Wik, 1994). Except for being exposed more often or for longer periods of time it is also possible, but not demonstrated (Green & Osborne, 1985), that women given a similar amount of exposure may be more sensitive to this role model learning than men. Finally, gender differences in adulthood might reflect extinction processes and that more men than women are exposed to their phobic object with fear extinction as the consequence. Processes other than exposure that result in extinction of phobias may also be more efficient or common in men. Because situational phobias are more prevalent in older than younger individuals some phobias could be acquired or elicited during adulthood. Alternatively, highly fearful individuals may be categorized as non-phobics earlier and phobics later in life. It should be noted that situational as compared to animal and mutilation phobia seem to be under substantially lower genetic control (Kendler et al., 1992). This is consistent with a hypothesis that some (situational) phobias are acquired during adulthood. In general, age differences in phobia prevalence were similar to age differences in fear intensity. Because age differences in phobias seem to parallel age differences in fear, this indicates that a similar set of factors may operate to determine fear and phobias. Thus, the most parismonius explanation is one of categorization. With increasing age, fear of animals was lower whereas situational fears were higher. The cross-sectional nature of the present study precludes any conclusion if this reflects alterations throughout the life span or is confounded with age. In a study of children aged 6-16 yr animal phobia had a negative correlation with age (Staley & O'Donnell, 1984) and specific animal fears seem to diminish in frequency with age both for boys and girls (Angelino & Shedd, 1953). The present data is consistent with the notion that this process is similar in adulthood for animal and mutilation fears and phobias but reversed for situational phobias. When prevalence data for specific phobia from the present study are compared with data from other studies using DSM-III-R based diagnoses (Table 1), it is clear that prevalence rates in the present study seem higher. This is particularly true compared to the ECA study and especially for men (cf. Robins et al., 1984). Prevalence rates are similar to those reported by Kendler et al. (1992) also studying women. It is difficult to compare prevalence rates because studies differ in phobia definitions, data collection methods, age, race, socioeconomic status of Ss, different time periods for risk estimation and varying number of objects and/or situations included to which Ss could report phobias. Thus, differences in prevalence rates may reflect sample selection procedures, response bias, differences in data collection procedures, alterations over time (reflecting willingness to admit, fears and phobias, or true differences). Also, the generality criterion, a decrease in global functionality has sometimes been assessed and included. When this is not assessed, prevalence figures will increase. This is true for the present study and also for the study of Kendler et al. (1992). According to Weissman, Myers and Harding (1978), self-report questionnaires of psychiatric symptoms as compared to interviews, tend to result in higher prevalence estimates, possibly overestimating the true prevalence. In the present study no effort was made to rate the intensity of avoidance, loss of control of fear or amount of interference with life. Thus, the possibility exists that relatively liberal subjective criteria for these questions were applied spontaneously by respondents, thereby producing high prevalence estimates. Also specific questions on a particular syndrom may give higher prevalence estimates, an observation made when personality disorders are diagnosed in epidemiological studies (Ekselius, 1994). We suggest that by being specific in our diagnostic approach and by not assessing global functioning our prevalence estimates are higher than those previously reported. Some limitations with the generality of the present study should be noted. All participants lived in the greater Stockholm area. In the ECA study the prevalence rate varied with cities (Boyd et al., 1990). Thus, findings from one place might not be representative of findings from another place. This could not be determined in the present study because only individuals in one city were studied. In short, we conclude that age and gender differences in phobia prevalence indicate specific phobias to be heterogenous with respect to sex and age distribution.
REFERENCES Agras, S., Sylvester, D. & Oliveau, D. (I 969). The epidemiology of common fears and phobia. Comprehensive Psychiatry, I0, 151-156. American Psychiatric Association (1987). Diagnostic and statistical manual of mental disorders (3rd edn, rev.). Washington, DC: American Psychiatric Association. American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders. Washington, DC: American Psychiatric Press. Angelino, H. & Shedd, C. (1953). Shifts in the content of fears and worries relative to chronological age. Proceedings of the Oklahoma Academy of Science, 34, 180-186. Bourden, K. H., Boyd, J. H., Rae, D. S., Burns, B. J., Thompson, J. W. & Locke, B. Z. (1988). Gender differences in phobias: results of the ECA community survey. Journal of Anxiety Disorders, 2, 227--241. Boyd, J. H., Rae, D. S., Thompson, J. W., Burns, B. J., Bourdon, K., Locke, B. Z. & Regier, D. A. (1990). Phobia: prevalence and riskfactors. Social Psychiatry and Psychiatric Epidemiology, 25, 314-323.
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Burvill, P. W. (1987). An appraisal of the NIMH epidemiologic catchment area program. Australian and New Zealand Journal of Psychiatry, 21, 175-184. Costello, C. G. (1982). Fears and phobias in women: a community study. Journal of Abnormal Psychology, 91, 280-286. Ekselius, L. (1994). Personality Disorders in the DSM-III-R. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, 484. Eysenck, H. J. (1985). Incubation theory of fear/anxiety. In Reiss, B. & Boutzin, R. R. (Eds), Theoretical issues in behavior therapy (pp. 83-105). New York: Academic Press. Faravelli, C., Degl'Innocenti, G. & Giardinelli, L. (1989) Epidemiology of anxiety disorders in Florence. Acta Psychiatrica Scandinavia, 79, 308-312. Fredrikson, M., Annas, P. & Wik, G. (1994). Epidemiology of aversive encounters and the development of phobia in a random cohort. Manuscript submitted. Fredrikson, M., Hugdahl, K. & Ohman, A. (1976). Electrodermal conditioning to potentially phobic stimuli in male and female subjects. Biological Psychology, 4, 305-314. George, L. K., Hughes, D. C. & Blazer, D. G. (1986). Urban/rural differences in the prevalence of anxiety disorders. The American Journal of Social Psychiatry, 4, 249-258. Green, G. & Osborne, J. G. (1985). Does vicarious instigation provide support for observational learning theories?: A critical review. Psychological Bulletin, 97, 3-17. Joyce, P. R., Bushnell, J. A., Oakley-Browne, M. A., Wells, J. E. & Hornblow, A. R. (1989). The epidemiology of panic symptomology and agoraphobic avoidance. Comprehensive Psychiatry, 30, 303-312. Kendler, S. K., Neale, M. C., Kessler, R. C., Heath, A. C. & Eaves, J. E. (1992). The genetic epidemiology of phobias in women. Archives of General Psychiatry, 49, 273-281. Kessler, R. C., McGonagle, K. A., Zhao, S. Z., Nelson, C. B., Hughes, M., Eshleman, S., Wittchen, H. U. & Kendler, K. S. (1994). Lifetime and 12-month prevalence of DSM-III-R Psychiatric Disorders in the United States. Archives of General Psychiatry, 51, 8-19. Lindal, E. & Stefhnsson, T. (1993). The lifetime prevalence of anxiety disorders in Iceland as estimated by the US National Institute of Mental Health Diagnostic Interview Schedule. Acta Psychiatrica Scandinavia, 88, 29-34. Marks, I. M. (1969) Fears and Phobias. London: Heinemann. Myers, J. K., Weissman, M. M., Tischler, G. L., Holzer, C. E., Leaf, P. J., Orvaschel, H., Anthony, J. C., Boyd, J. H., Burke, Jr, J. D., Kramer, M. & Stoltzman, R. (1984). Six-month prevalence of psychiatric disorders in three communities. Archives of General Psychiatry, 41, 959-967. Ost, L.-G. (1987). Age of onset in different phobias. Journal of Abnormal Psychology, 96, 223-229. Parker, G. (1987). Are the lifetime prevalence estimates in the ECA study accurate? Psychological Medicine, 17, 275-282. Pollard, C. A. & Henderson, J. G. (1987). Prevalence of agoraphobia: some confirmatory data. Psychological Reports, 60, 1305. Regier, D. A., Boyd, J. H., Burke, J. D., Rae, D. S., Myers, J. K., Kramer, M., Robins, L. N., George, L. K., Karno, M. & Locke, B. Z. (1988). One-Month Prevalence of Mental Disorders in the United States. Archives of General Psychiatry, 45, 977-986. Robins, L. N., Helzer, J. E., Weissman, M. M., Orvaschel, H., Gruenberg, E., Burke, Jr, J. D. & Regier, D. A. (1984). Lifetime prevalence of specific psychiatric disorders in three sites. Archives of General Psychiatry, 41, 949-958. Rose, R. J., Miller, J. Z., Pogue-Geile, M. F. & Cardwell, G. F. (1981). Twin-family studies of common fears and phobias. In Gedda, L., Parisi, P. & Nance, W. E., (Eds), Twin research, 3: intelligence, personality, and development (pp. 169-174). New York: Liss. Rosenhan, D. L. & Seligman, M. E. P. (1989). Abnormal psychology. New York: Norton. Schwab, J. J., Bell, R. A., Warheit, G. J. & Schwab, R. B. (1979). Social order andmental health. New York: Brunner/Mazel. Seligman, M. E. P. (1971). Phobias and preparedness. Behavioral Therapy, 2, 307-320. Staley, A. A. & O'Donnell, J. P. (1984). A developmental analysis of mothers' reports of normal children's fears. The Journal of Genetic Psychology, 144, 165-178. Weissman, M. M., Myers, J. K. & Harding, P. S. (1978). Psychiatric disorders in a US urban population: 1975-76. American Journal of Psychiatry, 135, 459--462. Wittchen, H. U. (1986). Epidemiology of panic attacks and panic disorders. In Hand, I. & Wittchen, H. U. (Eds), Anxiety and panic disorder. Berlin: Springer.
Pergamon
Behav. Res. Ther. Vol. 34, No. 1, pp. 33-39, 1996
0005-7967(95)00048-8
Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0005-7967/96 $9.50 + 0.00
Gender and age differences in the prevalence of specific fears and phobias M A T S F R E D R I K S O N 1'2., P E T E R A N N A S l, H / ~ K A N F I S C H E R j a n d G U S T A V W I K 3
~Department of Clinical Neuroscience, Karolinska Institute and Hospital, Sweden, 2Department of Clinical Psychology, Uppsala University, Box 1225, S-751 42 Uppsala, Sweden and 31nstitut fiir Experimentelle Audiologie, Westfiilische Wilhelmsuniversitgit, Miinster, Germany (Received 25 April 1995) Summary--Point prevalence of specific fears and phobias was determined in 704 respondents of 1000 randomly selected adults aged 18 70yr. A phobia for lightning, enclosed spaces, darkness, flying, heights, spiders, snakes, injections, dentists and/or injuries was defined if subjects reported a fear that was out of conscious control, interfered with life and lead to the avoidance of the feared object [American Psychiatric Association, 1994. Diagnostic and statistical manual of mental disorders (4th edn). Washington, DC: American Psychiatric Press.] Fear intensity was assessed using visual analogue scales. A factor analysis generally supported the classification of fears and phobias into: (1) situational phobias (lightning, enclosed spaces, darkness, flying and heights); (2) animal phobias (spiders and snakes); and (3) mutilation phobias (injections, dentists, injuries). Total point prevalence of any specific phobia was 19.9% (26.5% for females and 12.4% for males). In total, 21.2% women and 10.9% men met criterias for any single specific phobia. Multiple phobias was reported by 5.4% of the females and 1.5% of the males. Animal phobia had a prevalence of 12.1% in women and 3.3% in men. Point prevalence of situational phobia was 17.4% in women and 8.5% in men. For mutilation phobia no gender difference was observed, being presented in 3.2% of the women and 2.7% of the men. Women as compared to men gave higher fear ratings for all objects and situations. Inanimate object fears and phobias were more common in older than younger individuals. Animal fears were more intense in younger than in older individuals. Fear of flying increased and fear of injections decreased as a function of age in women but not in men. Thus, specific fears and phobias are heterogeneous with respect to sex and age distribution.
INTRODUCTION Phobias are defined as unreasonable fears, associated with the avoidance of objects or situations, that interferes with life (DSM IV, American Psychiatric Association, 1994). Phobias are categorized as specific, social or agoraphobias (DSM IV). At least 14 studies (see Table 1) have presented prevalence rates for different types of phobias. In the first epidemiological study performed when DSM (1952) defining criterias were used Agras, Sylvester and Oliveau (1969) reported a 6.3% point prevalence estimate of any specific and a 7.7% estimate of any phobia in a combined sample of men and women. Costello (1982) reported a 12-month prevalence rate of specific phobia in women varying between 4.9 and 12.5%, depending on the phobias that were included. A phobia was in that study defined as intense fear associated with the avoidance of a specific object. In the Epidemiological Catchment Area (ECA) surveys (Robins, Helzer, Weissman, Orvaschel, Gruenberg, Burke & Regier, 1984; Myers, Weissman, Tischler, Holzer, Leaf, Orvaschel, Anthony, Boyd, Burke, Kramer & Stoltzman, 1984; Regier, Boyd, Burke, Rae, Myers, Kramer, Robins, George, Karno & Locke, 1988; Boyd, Rae, Thompson, Burns, Bourdon, Locke & Regier, 1990), DSM-III-R (American Psychiatric Association, 1987) criteria were used to define phobia and prevalence rates of specific phobias varied from 2 to 26%. Part of the variation was due to location,, sex and time. The variation between cities could not be accounted for except that Myers et al. 0984) suggested that different wording related to prevalence differences. Wittchen (1986) used DSM-III criteria and observed a 6-month prevalence of 4.1% and a lifetime prevalence of 8% for specific phobia in men and women (Table 1). Kendler, Neale, Kessler, Heath & Eaves (1992) studying mono- and dizygotic twins reported a 20.5% lifetime prevalence of any DSM-III-R defined specific phobia including animal (insects, spiders, mice, snakes and bats) or situational (tunnels, other closed places, bridges, airplanes, other high places) phobias. Kessler, McGonagle, Zhao, Nelson, Hughes, Eshleman, Wittchen and Kendler (1994) recently presented results from the national comorbidity survey in the United States and reported a life-time prevalence of specific phobia of 6.7% in men and 15.7% in women. Part of the variation in prevalence is most likely due to the fact that in some but not other studies a decrease in the global assessment of functioning has been part of the phobia definition. Most studies treat the more circumscribed specific phobias separate from the less circumscribed social phobia and agoraphobia. However, studies mainly treat specific phobia as a single entity. Because specific phobias seem heterogeneous with respect to age at onset (Ost, 1987), genotype (Kendler et al., 1992; Rose, Miller, Pogue-Geile & Cardwell, 1981) and possibly evolutionary underpinnings (Seligman, 1971) there could be reasons to study the epidemiology of specific fears and phobias for different objects and situations separately. Rosenhan and Seligman (I 989), suggested that specific phobias could be grouped into three categories, namely: situational phobias, animal phobias and mutilation phobias. In the present study phobias of snakes and spiders was classified as "animal phobia". Phobia of lightning, enclosed spaces, darkness, flying and heights was classified as "situational phobia" *To whom all correspondence should be addressed at: Department of Clinical Psychology, Uppsala University, Box 1225, S-751 42 Uppsala, Sweden. 33
interview schedule DSMs
one-point 325
interview
1645
6-month more than 9000 18 and over DISc DSMillh
one-point 449 18~5 PSEd
intensity+
5.0-12.5% Calgary
2.3-7.3% 6.0-15.7% 3 ECAb cities
10.2-30.0%t
Florida
0.9-1.7% 1.5-2.6%
10.6%t
2.~8.6% 7.7-17.5% 0.9-3A% 4.2-7.8%
19.0% 2.9% 8.3%
DSMIll
lifetime 9543 18 and over DIS DSMIII
lifetime 657 2~63 DIS
3.8-14.5% 5.5% 8.5-25.9% 10.4% 3 ECA cities Munich
1.5-5.2% 5.3-12.5% 2,4% 3.2%
DSMIII
6-month 3648 18 and over DIS DSMIIIRi
ASIf
one-point 500
DSMIIIR
lifetime 18 572 18 and over DIS
7.2% 13.9%** 5 ECA cities
2.3% 3.2%
2.9% 7~7%**
9.2% 17.0%**
DSMIIIR
lifetime 1498 16~4 DIS
CPEc
5.9%t
3.9%t
0.36%
6.8% 14.6%
Pollard & Bourden e t al, Joyce e t al. Henderson 1987 1988 1989
9.5%-7.9% a 13.2%-16.6%* North Carolina St. Louis
1.7%-2.6% 2.5%-3.6% a
2.2%-4,6%* 6A%-7.9% t
Robins e t al. Wittchen George e t o,l. 1984 1986 1986
Table I. Prevalence a n d gender differences in phobias in different epidemiological studies Myers e t al, 1984
I 1.3%t
15.5%t
Costello 1982
structured interview DSMIIIR
lifetime 1110
0.09% 0.54% Florence
0.72% 0.27%
0.90%
DSMIIlR
1-month 18 571 18 and over DIS
5 ECA cities
5.1%t
1.3%t
2-9%t
6.2%t
Faravelli et al, Boyd e l al. 1989 1990
DSMIIIR
DIS
20.2% Virginia Twin registry Lifetime 2163
11.5%
8.7%
33.4%
Kendler e t al. 1992
DSMIV
one-point 704 18-70 questionnaire
12.4% 26.5%*" Stockholm
The present study
*P < 0.05 (reported P-value); **P < 0.01 (reported P-value); "['total prevalence. aRural-Urban; bEpidemiotogicat Catchment Area program; CChristchurch Psychiatric Epidemiology; dPrescnt State Examinations; ~Diagnostic Interview Schedule; rAnxiety Symptoms Interview; SDiagnostic and Statistic Manual o f mental disorders, 1952; hDiagnostic and Statistic M a n u a l o f mental disorders, 1980; ~Diagnostic and Statistic M a n u a l o f mental disorders, 3rd edition 1987.
Period of prevalence Sum of subjects Age of subjects Data collecting method Phobia definition
Men 7.7%t Women Agoraphobia + panic Men Women Social phobia Men Women Simple phobia Men Women Place Burlington
Any phobia
Agras el a/, Schwab e t al. 1969 1979
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35
and phobia of injections, dentists and injurys as "mutilation phobia". These situations and objects were chosen because they commonly elicit fear and phobia (of. Agras et al., 1969; Rosenhan & Seligman, 1989). Women generally display more phobias than men (Marks, 1969; Lindal & Stef~nsson, 1993). Furthermore, it has been reported (cf. Marks, 1969) that sex differences in specific phobias are present predominantly after puberty. However, it has only seldom been determined whether sex differences in specific fears and phobia prevail, increase or decrease throughout the adult lifecycle. Agras et al. (1969) reported lower fear ratings with increasing age but did not include estimates of phobias. The aim of the present study was to determine prevalence rates of phobias for lightning, enclosed spaces, darkness, flying, heights, spiders, snakes, injections, dentists and injuries in younger and older women and men. Point prevalence was chosen over other estimates since it has been argued that recall over more extended time periods might pose reliability problems (Burvill, 1987; Parker, 1987). Presence of phobia was determined using true/false questions based on DSM-IV criteria. Fear intensity was rated using visual analogue scales. Finally, by performing a factor analysis we studied if the three factor structure for specific fears and phobias, as suggested by Rosenhan & Seligman (1989), could obtain empirical support. METHOD Subjects Five hundred male and 500 female Ss from the greater Stockholm area, aged 18--70 yr, were randomly selected from a population-based registry (L-data). A questionnaire was mailed together with a stamped return envelope. Within 3 weeks, 242 men and 274 women had replied. After a reminding letter was sent out, 336 men and 384 women, a total number of 720 Ss, had returned the questionnaires. Five men and 11 women replied in ways impossible to interpret and were excluded. Thus, a total of 704 Ss were eligible for analyses. Questionnaires Questions on fear of snakes, spiders, lightning, enclosed spaces, darkness, flying, heights, injections, dentists and injuries were included. Based on DSM-IV criteria, the following true-false questions were used to define a phobia: (1) I give up things because of my fear; (2) My fear is greater than justified; (3) I cannot control my fear. If Ss answered all 3 questions in the affirmative, a phobia was defined for each object and/or situation. Subjects were classified as having no, single or multiple phobias. Subjects also completed visual analogue scale (VAS) ratings of fear for snakes, spiders, lightning, enclosed spaces, darkness, flying, heights, injections, dentists, injuries. Zero denoted "no fear at all" and 100 "maximal fear". Statistical methods Statistical tests included analyses of variance, factor analyses and chi-square tests. Data were analyzed using the Statistical Package for Social Sciences; Macintosh version 4.0. Means and confidence intervals are presented in order to increase comparability with other studies. RESULTS The mean ( + S D ) age was 41.5 yr (_+ 14.2) and 41.4 yr ( _ 14.0) for women and men respectively. To define relatively younger and older S s, a median (Md = 41.0) split approach resulted in an average ( + SD) age of 29.0 yr (6.5) in the younger and of 53.3 yr (+8.4) in the older group. Fears The factor structure obtained from factor analyses of VAS ratings resulted in three separate dimensions and generally supported the theoretically based structure of Rosenham and Seligman (1989), (see Table 2). To be included in a factor the item had to display a factor loading greater than 0.50. The injury item did not meet the criteria for the mutilation factor but displayed a 0.44 loading. However, the injury item had its highest loading in the mutilation factor and therefore was included in this factor. Table 3 gives visual analogue scale ratings of fear for each item and groups of items in younger and older men and women. Women reported significantly more intense fear than men for all separate items and groups of items (see Table 3). Fear ratings of animals, particularly of spiders, were higher in younger than older individuals. Lower fear ratings of lightning, heights and flying in younger than older Ss resulted in lower average situational fear intensity. Fear of injections was higher in the young (see Table 3). Two significant interactions between gender and age for fear intensity pertained to higher fear of flying and lower fear of injections in older than younger women, whereas ratings were similar in older and younger men. No other interactions reached significance. For fear of flying, younger women gave a rating of 18.4 and older of 27.1
Table 2. The factor structure of fears as determined by varimax rotation analysis Items Lightning Closed spaces Darkness Heights Flying Snake Spider Injections Dentist Injuries
Factor 1 (Situational fears)
Factor II (Animal fears)
Factor Ill (Mutilation fears)
0.64 0.69 0.50 0.67 0.75 ---
-----0.74 0.83
--------
----
----
0.84 0.75 0.44
36
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Table 3. Average (_+SD) visual analogue scale ratings of fear and confidence intervals (Cls) in men and women as well as young and old individuals as defined by a median split approach. Gender and age differences are tested by analysis of variance
Average animal fear Snakes Spiders
Cls
17.6 (18.1) 22.3 (24.4) 12.9 (19.0)
15.6-19,7 19.6-25.1 10.8-15.1
32.6 (25.5) 38.1 (31.5) 27.2 (29.6)
15.9-19.6 6.2-9.4 18.7-24.9 10.6-14.8 29.1-35.7 11.1-16.2
31.5 25.1 37.6 29.0 43.3 22.7
17.5 (24.9) 17.9 (25.9) 23.4 (24.8)
17.5-21.8 14.7-20.3 15.0-21.0 20.6-26.2
25.9 21.7 23.6 32.4
Younger
CIs
28.1 (24.0) 31.0 (29.0) 25.2 (28.7)
25.5-30.8 27.8-34.2 22.0-28.4
23.5 (23.0) 31.0 (29.9) 16.2 (22.6)
21.1-26.0 27.7-34.2 13.8-18.6
F(1,651) = 6.3** F(1,651) < 1 F(1,653) = 19.8"**
20.9-25.0 10.6-15.3 25.0-31.8 18.9-24.5 31.5-38.5 13.3-18.7
27.0 20.7 31.8 21.0 41.1 20.7
24.8-29.2 17.8-23.5 28.5-35.2 18.4-23.7 37.7~4.5 17.8-23.6
F(1,649) = F(I,651) = F(1,652) = F(1,654) < F(1,653) = F(1,652) =
7.0** 16.3"** 1.9 1 6.1"* 5.5*
21.6-26.2 19.9-26.1 18.7-24.9 23.6-29.6
22.2 (19.8) 16.9 (23.4) 20.4 (25.4) 29.9 (28.2)
20.1-24.4 14.4-19.4 17.7-23.1 26.8-32.9
F(l,651) F(1,653) F(1,652) F(1,654)
1.1 9.0** 1 2.2
Average situational fear 17.7 (16.1) Lightning 7.8 (14.3) Closed spaces 21.8 (28.0) Darkness 12.7 (18.4) Heights 32.4 (29.7) Flying 13.7 (22.6)
Average mutilation fear 19.6 (19.6) Injections Dentists Injuries
Average animal fear Snakes Spiders
Average situational fear 23.0 (18.2) Lightning 12.9 (21.2) Closed spaces 28,4 (30.7) Darkness 21.7 (25.1) Heights 35,0 (31.6) Flying 16,0 (24.2)
Average mutilation fear 23.9 (20.9) Injections Dentists Injuries
Gender differences Women Cls
Men
23,0 (28.4) 21.8 (27.7) 26.6 (27.2)
Total
CIs
30.0-35.3 34.8--41.4 24.1-30.3
25.6 (23.5) 30.7 (29.4) 20.6 (26.1)
23.8-27.4 28.5-33.0 18.6-22.5
F(I,657) = 73.9*** F(1,657) =50.8*** F(1,659) = 53.1"**
(20.3) (28.7) (31.9) (27.6) (33.3) (27.6)
29.4--33.7 22.0--28.1 34.2-40.9 26.1-31.9 39.8-46.7 19.8-25.6
25.0 (19.7) 17.0 (24.6) 30.1 (31.1) 21.4 (25.1) 38.2 (31.9) 18.4 (25.7)
23.6-26.6 15.1-18.8 27.8-32.5 19.5-23.3 35.8-40.6 16.5-20.4
F(1,655) =91.0"** F:1,657) = 91.5"** F(I,658) =45.1"** F(1,660) = 77.7*** F(1,659) = 19.7"** F(1,658) = 20.8***
(20.6) (26.9) (26.7) (29.5)
23.7-28.0 18.9-24.5 20.8-26.4 29.3-35.5
22.9 (20.3)
21.3-24.5 17.7-21.7 18.9-23.0 26.1-30.3
F(1,657) = 15.8"** F(I,659) =4.4* F(1,658) = 7.9** F(1,660) = 17.8"**
19.7 (26.0) 20.9 (26.5) 28.2 (27.7)
Age differences Older Cls
(20.7) (26.9) (31.5) (24.9) (31.8) (26.9)
Gender differences
Age differences
= = < =
*P <0.05; **P < 0.01; ***P < 0.001.
[t(162) = 2.749; P < 0.001] whereas younger and older m e n gave ratings of 12.9 and 13.9 respectively [t(162) < 1; NS]. F o r injections, VAS-ratings o f 27.6 and 15.8 were given by younger and older w o m e n [t(162) = 3.852; P < 0.001], whereas younger and older men had ratings o f 17.2 and 18.0 respectively [t(136) < 1; NS].
Phobias 19.9% of all S s met the criterias for any single or multiple specific phobia; 26.5% of all w o m e n and 12.4% of all men L~2(1) = 22.0; P < 0.01] (see Table 4). 16.3% met criterias for any m o n o s y m p t o m a t i c phobia and 3.6% met criterias for
Animsi
/
\
Mutilation
35 (5.2%)
[
~
12 {1.8%)
16 (2.3%} ~w~ 4 (0.6%) Situational 68 (10.0%)
Fig. 1. Distribution of individuals reporting animal, mutilation and situational phobias in a randomly selected cohort of 704 Ss.
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37
Table 4. Average (+SD) prevalence rates confidence intervals (Cls), gender and age differences of specific phobias in men and women as well as young and old individuals as defined by a median split approach. Gender and age differences are tested by chi square analysis Gender differences Women Cls %
Men %
Cls
Total %
Cls
Any animal phobia Snakes Spiders
3.3 (17.9) 2.4 (15.4) 1.2 (10.9)
1.4-5.3 0.7-4. I 0.0-2.4
12,1 ( 3 2 . 6 ) 8.3 (27.6) 5.6 (23.1)
Any situational phobia Lightning Closed spaces Darkness Heights Flying
8.5 (27.9) 0.3 ( 5 . 5 ) 2.4 (15.4) 0.0 ( 0 . 0 ) 6.3 ( 2 . 4 ) 1.8 (13.4)
5.4-11.5 0.34.9 0.7-4.1 0.0-0.0 0.4-9.0 0.4-3.3
Any mutilation phobia Injections Dentists Injuries
2.7 (16.3) 1.2 (10.9) 2.1 (14.4) 2.4 (15.4)
1.0-4.5 0.0-2.4 0.6-3.7 0.7-4.1
Younger %
CIs
Any animal phobia Snakes spiders
7.9 ( 2 . 7 ) 4.4 ( 2 . 1 ) 4.7 ( 2 . 1 )
Any situational phobia Lightning Closed spaces Darkness Heights Flying Any mutilation phobia Injections Dentist Injuries
;( 5
8.7-15.4 5.5-11.1 3.9-8.0
7.9 (27.1) 5.5 (22.9) 3.5 (18.5)
5.9-10.0 3.8-7.2 2.2-4.9
17.4 (38.0) 3.7 (19.0) 5.4 (22.6) 4.3 (20.2) 8.6 (28.0) 3.2 (17.7)
13.6-21.3 1.8-5.7 3.1-7.7 2.2-6.4 5.7-11.4 1.4-5.0
13.2 (33.9) 2.1 (14.4) 4.0 (19.6) 2.3 (14.9) 7.5 (26.4) 2.6 (15.8)
10.7-15.7 I.I-3.2 2.5-5.4 1.2-3.4 5.6-9.5 1.3-3.7
;(5(1) = ;(5(I) = ;(5(1) = ;(5(1) = ;(2(1) = Z2(I) =
12.3"* 10.0"* 4.0* 14.6"** 1.3 1.4
3.2 (17.7) 1.9 (13.6) 2.1 (14.5) 4.0 (19.7)
1.4-5.0 0.5-3.3 0.7-3.6 2.0-6.0
3,0 (17.0) 1.6 (12.4) 2,1 (14.4) 3,3 (17.8)
1.7-4.2 0.6-2.5 1.1-3.2 1.9-4.6
;(5(I) < ;(2(1) < ;(2(1) < z2(l) =
I 1 1 1.4
Z2(I) = 18.3"** j(2(1) = 11.6"* ;(2(1) = 10.0"*
Age differences Older Cls %
Z2
5.1-10.8 2.2-6.6 2.4-7.0
8.1 (2.7) 6.7 (2.5) 2.5 (I.6)
6.3-12.5 4.1-9.3 0.9-4.1
;(2(t) < 1 ;(2(1) = 1.7 Z2(I) = 2.4
9.4 ( 2 . 9 ) 0.9 (1.0) 2.6 ( 1 . 6 ) 2.1 ( 1 . 4 ) 5.3 ( 2 . 2 ) 1.8 (1.3)
6.3-12.5 0.1-1.9 0.9-4.4 0.5-3.6 2.9-7.7 0.4-3.2
16.8 ( 3 . 7 ) 3.3 (1.8) 5.3 (2.4) 2.2 (1.5) 9.9 ( 2 . 3 ) 3.3 (1.8)
12.9-20.6 0.1-5.2 3.0-7.6 0.7-3.8 6.7-12.9 1.5-5.2
;(2(1) = ;(2(1) = ;(2(1) = X2(I) < ;(2(1) = ;(2(1) =
8.2** 5.1" 3.2 1 5.0* 1.8
3.8 (I.9) 1.8 (I.3) 2.6 ( 1 . 6 ) 2.1 (1.4)
1.8-5.9 0.4-3.2 0.9-4.4 0.5-3.6
2.2 (1.5) 1.4 (1.2) 1.7 (1.3) 4.5 (2.1)
0.7-3.8 0.2-2.6 0.3-3.0 2.3-6.6
;(2(1) = ;(2(I) < Z2(I) < Zs(1) =
1.5 1 I 3.18
*P < 0.05, **P < 0.01, ***P < 0.001.
multiple phobias. There was overlap especially for situational and animal phobia, but less so for animal and mutilation phobia (see Fig. 1). Gender differences in the frequency of both monosymptomatic and multiple phobias were found. 21.2% of the female and 10.9% of the male population had a single specific phobia ~2(1) = 13,6; P < 0.01], while 5.4% of the female and 1.5% of the male population had multiple phobias [22(1) --- 7.6; P < 0.01]. Inanimate object phobia (13.2%) was the most c o m m o n phobia type followed by animal (8%) and mutilation phobia (3%). There were gender differences in animal and situational phobia but not in mutilation phobia. 17.4% of the females and 8.5% of the males had situational phobia (see Table 4). 12% of the female and 3.3% of the male sample displayed animal phobia. 3.2% of the female and 2.7% of the male sample had mutilation phobia (see Table 4). DISCUSSION Total point prevalence o f one or more specific phobia(s) was 19.9%; 26.5% for women and 12.4% for men. Roughly 16% had any specific phobia, while around 4% reported having multiple phobias. More women than men had animal and situational phobias. For mutilation phobia no gender differences were observed. A factor analysis indicated the existence of three separate and independent factors in specific phobia namely animal, situational and mutilation phobia. DSM-IV maintains that specific phobias m a y be categorized as animal type, natural environment type, blood-injection-injury type or situational type. Results from the factor analysis performed in the present study supported an animal, a blood-injection injury-mutilation and a situational phobia type. Storms and heights are given as examples of natural environment phobia in the DSM-IV. In the present study however, fears and phobias of thunderstorms and of heights clustered together with fear of enclosed places, darkness and flying. This suggests that the situational and the natural environment phobia type could share a c o m m o n underlying theme. Findings are in general agreement with previous studies reporting a higher phobia prevalence in women than men (el. Marks, 1969). This m a y reflect true differences, response bias or measurement precision problems. Confidence intervals estimate the precision o f the point estimate, and it is not obvious that measurements of mutilation phobia are less reliable than those of the other two phobia types at least not as reflected in wider confidence intervals. Therefore, variations in the precision of the measurement do not seem to account for gender differences. Sex differences were observed for animal and situational phobias but not for mutilation phobia. Data does not support that women are generally more willing to admit their phobias. Because mutilation phobias were reported equally often a m o n g the two sexes and since response bias most likely would affect reporting of all phobia types alike. This argues against response bias as an explanation of gender
38
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differences in phobias. Instead, women may be more vulnerable to animal and situational phobias. Gender differences may then reflect different genetic and/or environmental transmission patterns. To the best of our knowledge, no data has been reported to suggest different genetic vulnerability for phobia in men and women. However, this possibility is currently investigated in our laboratory. It is also conceivable that experiental factors differ between men and women. In experimental studies on aversive conditioning (Fredrikson, Hugdahl & Ohman, 1976) sex differences in acquisition and extinction rate were not observed. Thus, sex differences in fear-conditionability does not seem like a plausible single explanation for sex differences in phobia prevalence. It is conceivable that learning processes relevant to phobia acquisition, other than classical conditioning, could differ between the two sexes. For example, it has been suggested that the process of incubation, when fear intensity increases as a function of time, may operate in phobia acquirement (Eysenck, 1985). If traumatic experiences with, for example heights and lightning are equally common among the two sexes, data implicate that incubation should be more commonly observed in women than men. Thus data from the present study do not demonstrate but are consistent with an increased rate of socially transmitted fears and phobias in women as compared to men. Social transmission of fears and phobias might be more frequent or facilitated among women than men. Role modelling, the processes through which a fearful model transmits fear to an observer, seems to occur more frequently among women then men (Fredrikson, Annas & Wik, 1994). Except for being exposed more often or for longer periods of time it is also possible, but not demonstrated (Green & Osborne, 1985), that women given a similar amount of exposure may be more sensitive to this role model learning than men. Finally, gender differences in adulthood might reflect extinction processes and that more men than women are exposed to their phobic object with fear extinction as the consequence. Processes other than exposure that result in extinction of phobias may also be more efficient or common in men. Because situational phobias are more prevalent in older than younger individuals some phobias could be acquired or elicited during adulthood. Alternatively, highly fearful individuals may be categorized as non-phobics earlier and phobics later in life. It should be noted that situational as compared to animal and mutilation phobia seem to be under substantially lower genetic control (Kendler et al., 1992). This is consistent with a hypothesis that some (situational) phobias are acquired during adulthood. In general, age differences in phobia prevalence were similar to age differences in fear intensity. Because age differences in phobias seem to parallel age differences in fear, this indicates that a similar set of factors may operate to determine fear and phobias. Thus, the most parismonius explanation is one of categorization. With increasing age, fear of animals was lower whereas situational fears were higher. The cross-sectional nature of the present study precludes any conclusion if this reflects alterations throughout the life span or is confounded with age. In a study of children aged 6-16 yr animal phobia had a negative correlation with age (Staley & O'Donnell, 1984) and specific animal fears seem to diminish in frequency with age both for boys and girls (Angelino & Shedd, 1953). The present data is consistent with the notion that this process is similar in adulthood for animal and mutilation fears and phobias but reversed for situational phobias. When prevalence data for specific phobia from the present study are compared with data from other studies using DSM-III-R based diagnoses (Table 1), it is clear that prevalence rates in the present study seem higher. This is particularly true compared to the ECA study and especially for men (cf. Robins et al., 1984). Prevalence rates are similar to those reported by Kendler et al. (1992) also studying women. It is difficult to compare prevalence rates because studies differ in phobia definitions, data collection methods, age, race, socioeconomic status of Ss, different time periods for risk estimation and varying number of objects and/or situations included to which Ss could report phobias. Thus, differences in prevalence rates may reflect sample selection procedures, response bias, differences in data collection procedures, alterations over time (reflecting willingness to admit, fears and phobias, or true differences). Also, the generality criterion, a decrease in global functionality has sometimes been assessed and included. When this is not assessed, prevalence figures will increase. This is true for the present study and also for the study of Kendler et al. (1992). According to Weissman, Myers and Harding (1978), self-report questionnaires of psychiatric symptoms as compared to interviews, tend to result in higher prevalence estimates, possibly overestimating the true prevalence. In the present study no effort was made to rate the intensity of avoidance, loss of control of fear or amount of interference with life. Thus, the possibility exists that relatively liberal subjective criteria for these questions were applied spontaneously by respondents, thereby producing high prevalence estimates. Also specific questions on a particular syndrom may give higher prevalence estimates, an observation made when personality disorders are diagnosed in epidemiological studies (Ekselius, 1994). We suggest that by being specific in our diagnostic approach and by not assessing global functioning our prevalence estimates are higher than those previously reported. Some limitations with the generality of the present study should be noted. All participants lived in the greater Stockholm area. In the ECA study the prevalence rate varied with cities (Boyd et al., 1990). Thus, findings from one place might not be representative of findings from another place. This could not be determined in the present study because only individuals in one city were studied. In short, we conclude that age and gender differences in phobia prevalence indicate specific phobias to be heterogenous with respect to sex and age distribution.
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