Fig. 1.

a Cohort analysis observation follow-up period. ¹Vision Date is the date of implementing Vision software which is a computerised clinical management system used by the general practices to record patient information. ²Start Date is the latest of either the date of the individual patient registration at the general practice, Vision date, second birthday or the date of the study start Jan 1, 1996. ³Psychotropic medication classes included were: antidepressants, stimulants and non-benzodiazepine hypnotics and anxiolytics. ⁴The follow-up time of patients using ‘other psychotropic medication’ was censored once they received a prescription for an antipsychotic agent. An another follow-up period for them started on the first day of the antipsychotics prescription. R Date date of patient’s registration in the GP, ASD Dx autism spectrum disorder diagnosis, Rx drug prescription. b SCCS observation period