Channel 4: ascertaining diagnosis of autism and other conditions

27,919 participants (5.4%) indicated they had an autism diagnosis (cisgender males = 13,317; cisgender females = 13,934, transgender and gender-diverse = 668). Diagnoses of autism and other psychiatric conditions were asked using the question: “Have you been formally diagnosed with any of the following (please click all that apply?)”. For other psychiatric conditions, participants could choose from ADHD, bipolar disorder, depression, learning disorder, schizophrenia, and OCD. The wording of the question should typically preclude (though not completely eliminate) self-diagnosed individuals. Participants indicated they had the following diagnoses: ADHD (N = 19,300), bipolar disorder (N = 9025), depression (N = 122,829), learning disorder (N = 18,559), OCD (N = 13,115), and schizophrenia (N = 1321). These were not mutually exclusive, as individuals could endorse several diagnoses. In addition, participants provided information on their educational attainment and age (Supplementary Tables ^S1 and ^S2).