Psychiatric comorbidity among patients with gender identity disorder

Abstract

Aims:  Psychiatric comorbidity and mental instability seem to be important unfavorable prognostic factors for long-term psychosocial adjustment in gender identity disorder (GID). However, psychiatric comorbidity in patients with GID has rarely been assessed. In this study, we investigated the psychiatric comorbidity and life events of patients with GID in Japan.

Methods:  A total of 603 consecutive patients were evaluated independently by at least two senior psychiatrists at the GID clinic using clinical information and results of examinations.

Results:  Using DSM-IV criteria, 579 patients (96.0%) were diagnosed with GID. Among the GID patients, 349 (60.3%) were the female-to-male (FTM) type, and 230 (39.7%) were the male-to-female (MTF) type. Current psychiatric comorbidity was 19.1% (44/230) among MTF patients and 12.0% (42/349) among FTM patients. The lifetime positive history of suicidal ideation and self mutilation was 76.1% and 31.7% among MTF patients, and 71.9% and 32.7% among FTM patients. Among current psychiatric diagnoses, adjustment disorder (6.7%, 38/579) and anxiety disorder (3.6%, 21/579) were relatively frequent. Mood disorder was the third most frequent (1.4%, 8/579).

Conclusions:  Comparison with previous reports on the psychiatric comorbidity among GID patients revealed that the majority of GID patients had no psychiatric comorbidity. GID is a diagnostic entity in its own right, not necessarily associated with severe comorbid psychological findings.

GENDER IDENTITY DISORDER (GID) is characterized by a strong and persistent identification with the opposite sex and discomfort with one's own sex.¹ Compared with many other psychiatric disorders, GID is rare, with an estimated worldwide lifetime prevalence of 0.001–0.002%² or 0.0019–0.0024%.³ The incidence of GID patients who requested sex reassignment therapy was reported to be 0.14/100 000/year in Sweden.⁴ Thus, it has been difficult to establish demographic characteristics, and reports of large samples from countries outside of North America and Western Europe are extremely limited.^5,6

For most GID patients, a strong and persistent identification with the opposite sex and discomfort with one's own sex is a life challenge that often creates distress and carries potential stigmatization.⁶ It is reported that children with GID are at high risk for developing psychiatric problems⁷ and that the lifetime psychiatric comorbidity in GID patients is high.⁸ Moreover, psychiatric comorbidity and mental instability seem to be important unfavorable prognostic factors for long-term psychosocial adjustment in GID.^9,10 However, psychiatric comorbidity in a large number of patients with GID has rarely been assessed.^11,12 In this study, we investigated the psychiatric comorbidity and life events of patients with GID in Japan.

METHODS

Gender identity disorder clinic

The GID Clinic at Okayama University Hospital, the second oldest GID clinic in Japan, was established in Okayama in 1997. During the study period, the GID Clinic at Okayama University Hospital was the only special GID clinic in western Japan. It consists of four departments: psychiatry, urology, gynecology, and plastic and reconstructive surgery. The services at the GID Clinic include diagnosis, counseling, genetic testing, hormonal therapy, plastic surgery, and coordination of social services resources.

All aspects of the present study were approved by the Ethical Committee of Okayama University Hospital.

Subjects

A total of 603 consecutive Japanese patients examined at the outpatient GID Clinic of Okayama University Hospital between 1 April 1997 and 31 October 2005 were included in this study. All patients were comprehensively evaluated independently by at least two senior psychiatrists with a special interest in this area, and 579 of 603 patients (96.0%) fulfilled the criteria for GID according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). Four patients were excluded for transvestic fetishism, eight for homosexuality, five for schizophrenia, three for personality disorders, and four for other psychiatric disorders.

Of 579 patients diagnosed GID, 349 (60.3%) were the female-to-male (FTM) type, and 230 (39.7%) were the male-to-female (MTF) type. The mean age at first examination was 26.5 ± 6.1 year for the FTM GID patients, and 32.0 ± 10.2 years for the MTF type (P < 0.001; independent sample t-test, t value –8.116, degrees of freedom 575). More detailed demographic characteristics have been reported previously.⁵

Procedure

Of 579 GID patients, current psychiatric comorbidity was assessed independently by two senior psychiatrists, according to several clinical interviews and clinical records. All patients underwent a standard psychiatric evaluation to diagnose psychiatric comorbidities, such as schizophrenia or mood disorder, according to DSM-IV. The lifetime presence or absence of serious suicidal ideation and self mutilation was investigated by asking the following questions: ‘Have you ever seriously thought about committing suicide?’ and ‘Have you ever mutilated yourself (including suicide attempt)?’. All patients were evaluated by neurological and psychological examinations, and chromosomally and endocrinologically screened. All participants signed an informed consent form.

Comparisons of psychiatric comorbidity, suicidal ideation and self mutilation between MTF and FTM groups were performed by χ² test. Comparison of suicidal ideation and self mutilation between positive and negative psychiatric comorbidity groups were also performed by χ² test. The χ² test was applied to the data after unanswered questions were excluded.

Statistical analysis

Statistical analysis was conducted using SPSS 12.0J (SPSS Inc, Chicago, IL, USA). The χ² test and Student's t-test were used as outlined in the text. The significance level was set at P < 0.05.

RESULTS

Table 1 shows that current psychiatric comorbidity was significantly more common in the MTF patients than in the FTM patients, but that the lifetime positive history of suicidal ideation and self mutilation did not show such a significant difference between the MTF and FTM patients.

Table 1.  Psychiatric comorbidity, suicidal ideation, and self mutilation among patients with gender identity disorder

	n	Psychiatric comorbidity		Suicidal ideation			Self mutilation
		+	−	+	−	Unknown	+	−	Unknown
Psychiatric comorbidity, χ^2 = 5.663, P = 0.017; suicidal ideation, χ^2 = 0.305, P = 0.581; self mutilation; χ^2 = 0.172, P = 0.678.
Male-to-female	230	41	189	175	55	0	73	152	5
		(17.8%)	(82.2%)	(76.1%)	(23.9%)		(31.7%)	(66.1%)	(2.2%)
Female-to-male	349	38	311	251	88	10	114	220	15
		(10.9%)	(89.1%)	(71.9%)	(25.2%)	(2.9%)	(32.7%)	(63.0%)	(4.3%)
Total	579	79	500	426	143	10	187	372	20
		(13.6%)	(86.4%)	(73.6%)	(24.7%)	(1.7%)	(32.3%)	(64.2%)	(3.5%)

Current psychiatric diagnoses are shown in Table 2. Adjustment disorder (6.7%, 38/579) and anxiety disorder (3.6%, 21/579) were relatively frequent. Mood disorder was the third most frequent (1.4%, 8/579). One MTF patient had two diagnoses of social anxiety disorder and Asperger's disorder.

Table 2.  Current DSM Axis I and Axis II diagnosis of gender identity disorder patients (n = 579)

Diagnosis	Total	Male-to-female	Female-to-male
Axis I	79	41	38
Pervasive developmental disorders
Asperger's disorder	4	4	0
Mental disorders due to a general medical condition
Personality change	1	0	1
Substance-related disorders
Inhalant dependence	1	0	1
Schizophrenia and other psychotic disorders
Paranoid type	1	0	1
Disorganized type	1	0	1
Mood disorders
Major depressive disorder, recurrent	7	3	4
Bipolar I disorder, most recent episode depressed	1	1	0
Anxiety disorder
Panic disorder without agoraphobia	7	2	5
Obsessive-compulsive disorder	7	4	3
Social anxiety disorder	5	4	1
Generalized anxiety disorder	2	0	2
Somatoform disorders
Somatization disorder	4	3	1
Dissociative disorders
Dissociative amnesia	1	0	1
Adjustment disorders
With mixed anxiety and depressed mood	24	15	9
With depressed mood	6	2	4
With disturbance of conduct	4	2	2
Unspecified	4	2	2

Table 3 shows that positive histories of suicidal ideation were significantly more frequent in GID patients with current psychiatric comorbidity than without it in the total GID group and the FTM group, but not in the MTF group.

Table 3.  Comparison between gender identity disorder patients with and without psychiatric comorbidity: suicidal ideation

		n	Suicidal ideation
			Total			Male-to-female		Female-to-male
			+	−	?	+	−	+	−	?
χ^2 test (excluding unknown group): total, χ^2 = 5.844, P = 0.016; male-to-female, χ^2 = 0.531, P = 0.466; female-to-male, χ^2 = 6.886, P = 0.009. ?, unknown.
Psychiatric comorbidity	+	79	67	11	1	33	8	34	3	1
			(84.8%)	(13.9%)	(1.3%)	(80.5%)	(19.5%)	(89.5%)	(7.9%)	(2.6%)
Psychiatric comorbidity	−	500	359	132	9	142	47	217	85	9
			(71.8%)	(26.4%)	(1.8%)	(75.1%)	(24.9%)	(69.8%)	(27.3%)	(2.9%)
Total		579	426	143	10	175	55	251	88	10
			(73.6%)	(24.7%)	(1.7%)	(76.1%)	(23.9%)	(71.9%)	(25.2%)	(2.9%)

Table 4 shows that positive histories of self mutilation were significantly more frequent in GID patients with current psychiatric comorbidity than without it in the total GID group and the FTM group, but not in the MTF group.

Table 4.  Comparison between gender identity disorder patients with and without psychiatric comorbidity: self mutilation

		N	Self mutilation
			Total			Male-to-female			Female-to-male
			+	−	?	+	−	?	+	−	?
χ^2 test (excluding unknown group): total, χ^2 = 5.031, P = 0.025; male-to-female, χ^2 = 0.779, P = 0.377; female-to-male, χ^2 = 5.488, P = 0.019. ?, unknown.
Psychiatric comorbidity	+	79	34	42	3	15	24	2	19	18	1
			(43.0%)	(53.2%)	(3.8%)	(36.6%)	(58.5%)	(4.9%)	(50.0%)	(47.4%)	(2.6%)
Psychiatric comorbidity	−	500	153	330	17	58	128	3	95	202	14
			(30.6%)	(66.0%)	(3.4%)	(30.7%)	(67.7%)	(1.6%)	(30.5%)	(65.0%)	(4.5%)
Total		579	187	372	20	73	152	5	114	220	15
			(32.3%)	(64.2%)	(3.5%)	(31.7%)	(66.1%)	(2.2%)	(32.7%)	(63.0%)	(4.3%)

DISCUSSION

Psychiatric comorbidity

A comparison with previous reports on the psychiatric comorbidity among GID patients is shown in Table 5. Studies using the structured clinical interview revealed a relatively high comorbidity rate of Axis I disorders (30–67%),^8,9,12 while studies without a structured interview showed a lower comorbidity rate of Axis I disorders (4–19%).¹¹ The possibility that clinical diagnosis without a structured interview missed psychiatric comorbidity among GID patients cannot be denied. However, in this study, two senior psychiatrists independently assessed current psychiatric comorbidity. Therefore, we suppose that our data are considerably reliable.

Table 5.  Psychiatric comorbidity of gender identity disorder patients: comparison with previous reports

Author	Bodlund & Kullgren (1996)		Cole et al. (1997)		Haraldsen & Dahl (2000)	Hepp et al. (2005)		Present study (2010)
^† Frequency, Frequency of psychiatric comorbidity (Axis I).
Diagnostic criteria	DSM-III-R		DSM-IV		DSM-III-R/IV	DSM-IV		DSM-IV
Structured interview	SCID		(−)		SCID I	SCID I		(−)
Sex	Male-to-female	Female-to-male	Male-to-female	Female-to-male	Male-to-female + female-to-male	Male-to-female	Female-to-male	Male-to-female	Female-to-male
Total (n)	10	9	318	117	86	20	11	230	349
Frequency^†	3 (30%)	6 (67%)	18 (6%)	5 (4%)	28 (33%)	8 (40%)	4 (36%)	41 (19%)	38 (12%)

Haraldsen and Dahl reported that transsexual patients selected for sex reassignment showed a relatively low level of self-rated psychopathology, suggesting that the view that transsexualism is a severe mental disorder is doubtful.¹² Cole et al. reported that less than 10% of GID patients evidenced problems associated with mental illness and that transsexualism is usually an isolated diagnosis, not part of any psychopathological disorder.¹¹ Most data including our data and previous studies using structured interviews showed that the majority of GID patients had no psychiatric comorbidity (Table 5).

Suicidal ideation and self mutilation

Surprisingly, the percentage of GID patients who have experienced suicidal ideation or self mutilation is very high (suicidal ideation, 426/579, 73.6%; self mutilation, 187/579, 32.3%) (Table 1). The intimate relationship between GID patients and suicidal ideation or self mutilation suggests two possibilities. One is that suicidal ideation is due to psychiatric comorbidity of GID patients and the other is that GID patients themselves have a tendency to experience suicidal ideation or self mutilation.

Among GID patients without current psychiatric comorbidity, 71.8% of patients have thought seriously about committing suicide (Table 3), and 30.6% of patients have performed self mutilation (Table 4). These figures are high and showed that GID patients have a tendency to experience suicidal ideation or self mutilation that is not due to psychiatric comorbidity. It is quite recently that GID has been recognized socially as a disease in Japan. Therefore, the harsh circumstances in which most GID patients have lived in Japan might influence the high rate of suicidal ideation or self mutilation.

Comparison between female-to-male and male-to-female groups

The percentage of patients with current psychiatric comorbidity was lower among FTM patients than among MTF patients. Previous reports that include large samples are extremely limited (Table 5). Cole et al. showed that psychiatric comorbidity is more frequent among MTF patients, as it is in ours.¹¹ Haraldsen and Dahl did not distinguish the frequencies of psychiatric comorbidity of MTF and FTM patients.¹²

The frequency of suicidal ideation and self mutilation is not different in our MTF and FTM patients (Table 1). However, a relationship of suicidal ideation and self mutilation to psychiatric comorbidity is evident in the FTM group, but not in the MTF group (Tables 3,4). As a result, FTM patients with psychiatric comorbidity had a higher tendency to suffer from suicidal ideation and self mutilation (suicidal ideation 89.5%, self mutilation 50.0%). In this study, the mean age of FTM patients (26.5 years) is younger than that of MTF patients (32.0 years). The difference of the mean age between FTM and MTF patients might affect the relationship of suicidal ideation and self mutilation to psychiatric comorbidity.

Limitation of this study

Some limitations of this study have to be considered. First, this study is a clinic-based study rather than a field study. Therefore, the sample is large, but not necessarily representative of all GID individuals. In our study, 60.3% were FTM GID patients, and 39.7% were the MTF type. One significant factor affecting the proportion of each diagnosis in this study may be the referral bias because in Japan MTF GID patients can obtain vaginoplasty relatively easily, while the GID Clinic of Okayama University Hospital is the only facility in western Japan that can perform FTM surgery. As a result, general psychiatrists may refer patients with FTM GID patients to our center.

Second, psychiatric comorbidity is diagnosed according to DSM-IV, but the structured clinical interview for DSM-IV was not used. However, two senior psychiatrists independently performed clinical interview and discussed the diagnosis. Thus, we suppose, clinical diagnosis is considerably reliable.

CONCLUSIONS

Comparison with previous reports on the psychiatric comorbidity among GID patients revealed that majority of GID patients had no psychiatric comorbidity. GID is a diagnostic entity in its own right, not necessarily associated with severe comorbid psychological findings. However, the harsh circumstances in which most GID patients have lived in Japan might influence the high rate of suicidal ideation or self mutilation in GID patients.

ACKNOWLEDGEMENTS

We thank Ms Ogino and Ms Kanamori for their skillful assistance. This study is partly supported by a grant from the Zikei Institute of Psychiatry.