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Cass Review on co-occurring problems: autism, ADHD, depression and anxiety

Young people referred to a gender clinic more often than average have co-occurring mental health problems or neurodiversity. The Cass Review describes these figures from the University of York's systematic review and advises that these problems are also treated as part of care (source, chapter 5).

The figures

From the York review of referred children and young people (paras 5.27 and 5.40, tables 2 and 3 of the report), the following picture emerges:

• Autism: on average 9 percent (confidence interval 6 to 11 percent; range per study 0 to 26 percent). ADHD: 10 percent (7 to 13 percent; range 2.5 to 27 percent).
• Depression: 38 percent (31 to 45 percent; range 3 to 78 percent). Anxiety: 38 percent (31 to 46 percent; range 8 to 100 percent). Eating disorders: 5 percent (2 to 8 percent).
• According to the report, adverse childhood experiences are common, but few studies reported them. In an audit of the first 124 referrals to the English clinic GIDS (Di Ceglie et al., 2002), 42 percent had lost one or both parents, mainly through separation, and physical abuse was documented in 15 percent of cases (paras 5.48 to 5.50).
• Sexual orientation: in a GIDS study (Holt et al., 2016), of the birth-registered females 68 percent were attracted to females and 21 percent were bisexual; of the birth-registered males, 42 percent were attracted to males and 39 percent were bisexual (para 8.30).

The report also notes that some research suggests transgender and gender-diverse people are three to six times more likely to be autistic than cisgender people (Warrier et al., 2020; para 5.41).

Diagnostic overshadowing

The Cass Review uses the term "diagnostic overshadowing" in connection with how services are organised: young people and families said that referral to a service focused only on gender meant that children with several issues had them dealt with in isolation by different services (GIDS, CAMHS, general practice), without considering how they affect each other (para 17.8). A long wait can, according to the report, also lead to deterioration of co-occurring mental health problems (para 17.4). The report advises that standard psychological and psychopharmacological treatments be used to manage the associated distress and co-occurring conditions.

Autism in girls

Clinicians the Cass Review spoke to see teenage girls with good cognitive ability who are articulate but struggling with gender identity, suicidal ideation and self-harm; in some of them, undiagnosed autism is the common denominator, which is often missed in adolescent girls (para 5.42). Clinical guidelines exist for autism with gender dysphoria: the consensus guideline by Strang and colleagues (2018) assumes an extended diagnostic period (source). See also Littman's ROGD research.

What is known about desistance

The Cass Review writes that early studies suggested that in about 15 percent of pre-pubertal children with gender incongruence this persisted into adulthood; later research found 10 to 33 percent for children who met formal diagnostic criteria. The majority of those children became cisgender adults attracted to the same sex (para 2.6). The report points out that it is unclear what these data say about the group now presenting in puberty (para 14.34). See also desistance research and detransition research.

What other bodies say

According to the Cass Review, several guidelines specify that mental health difficulties should be managed and/or were unlikely to impact treatment (para 14.15). The Danish review article lists substance abuse, suicidal thoughts, self-harm and marked psychological distress as contraindications for hormone treatment (source); see also Denmark, SBU (Sweden), COHERE (Finland) and Ukom (Norway). The Dutch Health Council wrote in June 2026 that young people who have presented in recent years more often have co-occurring psychosocial problems, for example autism, mood problems or ADHD, and that research is needed on the group now presenting (source). See also the VUmc protocol and the Dutch Protocol.