Gender-affirming hormone therapy reduces psychological distress in transgender people: systematic review

Gender-affirming hormone therapy reduces depressive symptoms and psychological distress in transgender people, according to a groundbreaking systematic review of research in the field.

The new study, led by Amsterdam University Medical Centers and the University of Exeter, reviewed 46 relevant journal articles. The research reviewed included a mix of studies based on interviews, comparisons of people who had taken hormones and those who had not, and analysis of data over time from groups of people who were undertaking hormone therapy. Participants involved in the studies came from a broad range of age groups, but the review focused only on gender-affirming hormone therapy via cross-sex hormones, not the possible effects of puberty blockers or other interventions.

The studies varied in size and quality, often with a substantial risk of bias, and focused on a range of different groups, across varying social demographics. The new review, funded by the European Research Council and published in Nature Human Behaviour, aimed to analyse their results to draw out common findings and identify research gaps.

Gender-affirming hormone therapy is the most common form of medical intervention used by transgender people. It changes a person’s physical appearance to better align with their gender identity. Once they have started the therapy, transgender people are usually instructed to continue it for the rest of their lives.

Previous evidence has shown that transgender people struggle disproportionately with their own mental health and in their social lives. As a result, there is a need to better understand the psychological consequences of hormones, as some previous research has suggested they may have a biological effect on aspects of psychosocial functioning; such as wellbeing, self-control and trust. However, research findings have often been mixed or inconclusive, and up until now there has been no systematic research into these effects.

This new research looked at the key areas of psychosocial functioning – how people function across areas such as well-being, self-control and trust.    These areas shape how people relate to themselves as well as others, and better functioning  has been shown to lead to healthier experiences in relationships and decrease social isolation and loneliness.

Dr David Matthew Doyle from Amsterdam University Medical Centers is leading this research. He said: “This work is vital in trying to achieve health equity for transgender people, who have disproportionately high levels of depression and anxiety as well as other mental health conditions, and seek out hormone therapy to become more comfortable in their bodies and often also in their social lives. Overall, we found that the quality of research in this important field, although improving, is generally limited, and studies have largely focused on medical effects of hormones, with little attention given to the psychosocial impacts that are crucial to sense of self and maintaining relationships. The most consistent finding across all studies in our review is that gender-affirming hormone therapy reduces depressive symptoms and psychological distress in transgender people, but we don’t know if this is caused by the biological effects of hormones or other related factors. 

“While there is also some evidence of improvements in quality of life and a positive change in interpersonal functioning, the findings were more inconsistent. That’s why further high-quality research is crucial, and we have already begun robust studies to isolate the biological effects of hormones from other psychological and sociocultural mechanisms.” 

The study found inconsistent or ambiguous results across other areas, with some evidence that there may be a difference between masculising and feminising hormone treatment in some areas, that would warrant further investigation.

Co-author Professor Manuela Barreto, of the University of Exeter, said: “As NHS waiting lists for hormone therapy clinics in the UK are extremely long, we need to produce a better and more robust evidence base with urgency, to ensure we are providing the best possible futures for transgender people. Acknowledging and attending to the psychosocial effects of interventions such as hormone therapy can prevent the need to access mental health services, which are also overwhelmed. We need better designed research that involves transgender people from the start, so we can understand both the biological and psychosocial aspects of therapy and improve care.” 

The paper is entitled ‘‘A Systematic Review of Psychosocial Functioning Changes after Gender-Affirming Hormone Therapy Among Transgender People”, and is published in Nature Human Behaviour.