Mental health articles

Aetiology of gender identity disorder as follows:

Genetic factors

One of the very few studies of the genetic processes in GID, reported by Coolidge et al., found 2 per cent of their sample of over 300 MZ and DZ twins showed some evidence of gender identity disorder symptomatology based on self-report measures. Applying statistical modelling to their data, they found that 62 per cent of the variance in reported symptoms could be attributed to biological factors; 38 per cent was attributable to environmental factors. These data led the investigators to suggest that the causes of GID were primarily biological – not psychological.

Biological factors

Although most commentators, and the genetic data, suggest that GID is primarily the result of biological processes, what these are is far from clear. Studies of sex hormonal disturbance in adulthood are surprisingly diffi cult to conduct, because many people with GID take hormones of the opposite sex either as part of a treatment programme or by purchasing them on the black market. Despite these interpretive diffi culties, what evidence there is does not support a hormonal explanation. Summarizing the evidence, Gladue reported few, if any, hormonal differences between men with GID, male heterosexuals and male homosexuals. Similarly negative results have been found in women. Meyer-Bahlung  found some women with GID had elevated levels of male hormones, but most did not. A variant of the hormonal explanation is that abnormal levels of prenatal hormones may infl uence behaviour, and possibly gender identity. This may affect both sexes. The female children of women who have taken precursors to male hormones during pregnancy to prevent uterine bleeding tend to express high levels of tomboyish behaviour in preschool years. Boys whose mothers have taken female hormones while pregnant tend to be less boyish than their peers and to engage less in rough-and-tumble play. However, there is no evidence that either group of children dislike their gender. Although a number of studies have failed to fi nd any differences between the brains of people with and without gender identity disorder, some studies have found evidence to suggest a neurological substrate to this disorder. Zhou et al. conducted autopsies on the brains of six people who had changed their sex from male to female. They found an area of the brain, known as the bed nucleus of stria terminalis (BST), within the hypothalamus to be much smaller than is typically found in men. Indeed, the size of the BST matched that typically found in women, which is usually about half the size of that found in men. In a further investigation of this phenomenon, Kruijver et al. examined the number of somatostatin-expressing neurons in the BST. They found the same pattern of neurological fi ndings. The number of these neurons in the BSTs of male-to-female transsexuals was similar to those in the females’ BST, while the number of these neurons of a female-to-male transsexual was in the male range. What this difference actually means is not clearly understood, although the BST is known to regulate sexual activity in male rats. It is possible, therefore, that this may contribute in some way to GID. Several research groups have measured differences between people with and without GID on more general neuropsychological tasks including those, such as rotation, visualization and verbalization tasks, whose performance typically differs between the sexes. Haraldsen et al., for example, found that untreated people with GID performed on cognitive tests in ways that were predicted by their biological sex, not their gender identity – suggesting few neurological differences between people with GID and those without such issues. By contrast, Schöning et al. found differences in areas of brain activation between untreated men with and without GID during spatial rotation tasks, suggesting that there are neurological differences between the two groups. Interestingly, at least one study in which performance on cognitive and other tasks has been assessed during hormone therapy for GID has shown the extent to which the brain is susceptible to hormonal treatment. Van Goozen et al. found that among women transforming to men, administration of androgens was associated with signif i cant increases in aggressiveness, sexual arousability and spatial ability, and reduced scores on verbal fl uency tasks. For the male-to-female group, the opposite constellation of outcomes was observed: anger and aggression proneness, sexual arousability and visuo-spatial ability decreased, while verbal fl uency improved. Unfortunately, several more recent studies including that of Schöning et al. have failed to fi nd this pattern of results.

Psychoanalytic explanations

Psychoanalytic explanations suggest that male transsexuals have an ambiguous core gender identity. According to Ovesey and Person, male transsexualism originates from extreme separation anxiety early in life before the individual has fully established his own sexual identity. To alleviate this anxiety, the individual resorts to fantasy of symbiotic fusion with the mother. In this way, mother and child become one and the danger of separation is nullifi ed. In the transsexual’s mind, he literally becomes the mother, and to sustain this fantasy attempts to revert his core identity from male to female. To explain the desire for the removal of the penis, Ovesey and Person  noted that the transsexual does not experience castration anxiety, as do most boys. Instead, they experience anxiety that continues until they are castrated. The penis is clear evidence that they have failed to psychically fuse with the mother. For the same reason, they reject the act of homosexuality, as this would also acknowledge them as male. They prefer to reject any sexual experience, and generally have little or no experience of sex, even masturbation. In sum, the motivation for security takes priority over motivation for sexuality, as a result of fear of early maternal abandonment.

Tags: causes, disorder, gender identity disorder