From 2010 to 2020, four patients were known or suspected to have died by suicide, out of about 15,000 patients (including those on the waiting list)

Between 2010 and 2020, four suicides were identified among approximately 15,000 young people referred to the Tavistock Gender Identity Development Service. Two of the individuals were on the waiting list and two had already been seen by the clinic.

Overall, four deaths among about 15,000 referrals represented a cumulative proportion of approximately 0.03%. Biggs noted that this proportion was orders of magnitude lower than the percentages of transgender adolescents reporting suicide attempts in survey studies, highlighting the distinction between suicide attempts and suicide deaths.

Using an estimated 30,080 patient-years of follow-up, Biggs calculated an annual suicide rate of 13 per 100,000 (95% confidence interval 4-34), approximately 5.5 times higher than that of the general UK population of adolescents of similar age after adjustment for sex composition. He noted that accompanying psychiatric conditions, including autism, depression, and eating disorders, may contribute to the elevated risk. However, because comparable suicide rates for young people receiving other NHS mental health services were unavailable, the extent to which these conditions explained the difference could not be determined.

^{Biggs, M. (2022). Suicide by clinic-referred transgender adolescents in the United Kingdom. Archives of Sexual Behavior, 51, 685-690. https://doi.org/10.1007/s10508-022-02287-7}