Psychological effects of exogenous testosterone on female-to-male transsexuals: A longitudinal study

The aim of the current study is to examine the effects of exogenous testosterone on multiple mental health domains in female-to-male transsexuals (FTMs). While previous US longitudinal studies have examined the physical effects of exogenous testosterone on FTMs, no US study has examined the psychosocial or cognitive effects of testosterone on FTMs longitudinally. In the current study, adult male and female control participants from the University of Houston and surrounding Houston community and FTMs from all over the US were assessed on cognitive functioning (local participants only) psychosocial functioning including depression, anxiety, stress, quality of life, self esteem, emotional reactivity, as well as gender role and psychopathology three times over a one year period. Controls were recruited to match FTMs (n = 79) on age and education level (n = 154). FTM participants completed measures initially before they begin testosterone treatment (T1, n = 79), three months later (T2, n = 54) and ten months to one year later (T3, n = 39). Male (n = 70; 56; 38) and female (n = 84; 61; 51) controls were measured in the same time intervals. Resulted showed that FTMs experienced decreases in gender dysphoria over their first year on testosterone. FTMs were not found to differ from males or females on verbal or spatial intelligence at T1, and by T3 a trend was found for an interaction of time x gender on spatial intelligence with FTMs’ spatial performance increasing more than controls by T3. While FTMs initially displayed poorer psychosocial functioning than controls, by T3 they appeared to be similar to controls on all variables except for self-esteem, where they displayed lower scores than males. In terms of gender role, while FTMs were not found to over-confirm their masculinity, they consistently displayed lower femininity scores than both males and females over all three time points. At the initial assessment, FTMs displayed higher scores on the MMPI-2 Psychopathic deviate scale and the Masculinity/femininity compared to male and female controls and on the Depression, Paranoia, Psychasthenia, Schizophrenia, and the Social Inversion scales compared to males. After a year of testosterone use, FTMs only differed from females on Masculinity/femininity and no longer differed from males on the Psychopathic deviate, Paranoia, or Psychasthenia scales. Contrary to the idea that beginning hormone treatment is a stressful experience, FTMs’ levels of stress actually decreased rapidly. No iatrogenic psychological effects of testosterone were found. Overall findings indicate that FTMs become more psychologically healthy after three months of using exogenous testosterone and these effects are maintained for their first year receiving testosterone treatment.