The present study aimed to investigate differences in personality traits among male-to-female (MtF), female-to-male (FtM) gender identity disorder (GID) subjects and non-transsexual male (M) and female (F) controls. Subjects were 72 MtF and 187 FtM GID subjects without psychiatric comorbidities together with 184 male and 159 female non-transsexual controls. Personality traits were assessed using a short version of the Temperament and Character Inventory (TCI-125). Group comparisons were made by two-way ANOVA. Statistical significances were observed as follows: 1) lower novelty seeking in FtM than in M or MtF, 2) higher reward dependence in FtM than in M, 3) higher cooperativeness in FtM than in M or MtF, 4) the highest self-transcendence in MtF among all the groups. The highest self-transcendence in MtF subjects may reflect their vulnerable identity and constrained adaptation to society as the minority. Nevertheless, higher reward dependence and cooperativeness in FtM subjects can be related to more determined motivation for the treatments of GID and might promise better social functioning and adjustment than MtF subjects.
The GID patients were diagnosed according to the criteria of ICD-10 (World Health Organization, 1993) and DSM-IV-TR (American Psychiatric Association, 2000). Diagnosis was made by more than 2 well-trained psychiatrists, in which transvestism was excluded, and only transsexualism was considered. Persons with gender identity disorder (GID) usually have kept uncomfortable feeling to their biological sex since their early childhood. The friction between mind and body, i.e., unwanted secondary-developed biological sex characteristic vs. unmet desire for sex reassignment, reaches its peak around their adolescence. Accordingly, GID subjects are sometimes accompanied by psychiatric comorbidities (Hepp et al., 2005, de Vries et al., 2011a and Terada et al., 2012a) and behavioral/adjustment problems (Terada et al., 2011 and Terada et al., 2012b). According to previous reports, the prevalence of psychiatric comorbidity ranged from 17.8% to 39% (Hepp et al., 2005, de Vries et al., 2011a and Terada et al., 2012a), whereas school refusal as an adjustment problem (29.2%) (Terada et al., 2011) and self-mutilation as a behavioral problem (31.8%) (Terada et al., 2012b) were also found in patients with GID.
Meanwhile, differences in prevalence and severity of psychiatric comorbidity in male-to-female (MtF) and female-to-male (FtM) GID patients have been also pointed out (Hoshiai et al., 2010 and de Vries et al., 2011a). The prevalence of the overall psychiatric comorbidities was higher among MtF patients (19.1%) than that among FtM patients (12.0%) (Hoshiai et al., 2010). Likewise, MtF patients showed higher incidences of mood disorders (20.8% vs. 3.8%) and social anxiety disorder (15.1% vs. 3.8%) compared with FtM patients (de Vries et al., 2011a). Furthermore, MtF patients more often suffered from two or more comorbid diagnoses (22.6%) than FtM patients (7.7%) (de Vries et al., 2011a). Multicenter studies on sociodemographic features revealed that FtM displayed significantly better social functioning (Fisher et al., 2013), while MtF conceptualized themselves as more vulnerable and deficient (Simon et al., 2011).
In our clinical practice, FtM patients generally have unbudging gender orientation and consistent desire for sex reassignment whereas gender orientation and treatment-seeking behavior in MtF patients tend to be more easily influenced by their circumstances and situations than those in FtM patients. In fact, the proportion of FtM patients who had marriage as a female is very low, and very few had children, while MtF-type GID patients seem to be less homogeneous and have more confused gender orientation (Okabe et al., 2008).
It has been recently suggested that some differences in personality traits exist between MtF and FtM subjects, e.g., higher harm avoidance, reward dependence and self-transcendence in MtF than those in FtM (Gómez-Gil et al., 2013) assessed by the Temperament and Character Inventory (TCI), which was developed by Cloninger et al. (1994). However, studies focusing on personality traits in GID patients are still few. Considering transcultural effects, personality traits in GID subjects need to be re-examined in different ethnic populations.
TCI (Cloninger et al., 1994) consists of novelty seeking, harm avoidance, reward dependence and persistence, which are associated with activation, inhibition, maintenance and preservation of behavior, respectively. Character dimensions are classified into self-directedness, cooperativeness and self-transcendence, which reflect the concept of self as an autonomous individual, a harmonization with humanity/society and an integral part of the universe, respectively. TCI has been widely used in clinical researches as a probe for premorbid personality factors for depressive disorders (Cloninger et al., 2006 and Farmer and Seeley, 2009).
Therefore, the present study aimed to comprehensively investigate differences in personality traits using TCI in Japanese MtF and FtM patients with GID, including comparison with non-transsexual control subjects.
