Does testosterone treatment increase anger expression in a population of transgender men?

Background: The acquisition of phenotypic male features in transmen with gender dysphoria requires testosterone treatment. The suppression of menses is 1 of the most desired effects. The relation between testosterone levels and human aggressive behavior has been described. However, the effects of testosterone on anger expression have been poorly investigated in trans-persons. Aim: To assess the effects of testosterone treatment on anger expression in transmen using a validated self-report questionnaire (Spielberger’s State-Trait Anger Expression Inventorye2 [STAXI-2]). Methods: 52 transmen diagnosed with gender dysphoria were evaluated before (T0) and at least 7 months after (T1) initiation of continuous gender-affirming testosterone treatment. Sociodemographic characteristics, anthropometric parameters, diagnosis of psychiatric disorders, current psychopharmacologic treatments, and life events were investigated at T0. Outcomes: STAXI-2 scores, serum testosterone, and estradiol levels at T0 and T1 were compared. Results: Most of the sample (61.5%, n ¼ 32) had no Axis I or II comorbidity. All subjects at T1 achieved significantly higher serum testosterone levels (5.67 ± 3.88 ng/mL), whereas no significant difference in estradiol levels was observed from T0 to T1. At T1 only 46.2% (n ¼ 24) of the sample achieved iatrogenic amenorrhea, whereas most of the sample had persistent regular bleedings. A significant increase in STAXI anger expression and anger control scores from T0 to T1 was recorded. Patients with persistent bleedings and Axis I disorders seemed to have higher odds of expressing anger. However, circulating testosterone levels at T1 did not influence anger expression. Clinical Implications: Interestingly, despite the increase of anger expression scores, during continuous testosterone treatment, there were no reports of aggressive behavior, self-harm, or psychiatric hospitalization. Strengths and Limitations: A limitation to this study is that although the STAXI-2 is a well-validated instrument measuring anger expression, it is a self-report psychometric measure. Conclusion: This study demonstrates that during 7 months of continuous gender-affirming hormonal treatment, anger expression and anger arousal control increased in transmen. Persistence of menstrual bleedings and Axis I disorders, but not circulating testosterone levels, were predictive of the increase in anger expression score. Continuous psychological support to transmen during gender-affirming hormonal treatment was useful to prevent angry behaviors and decrease the level of dysphoria.