As reported in Table 2, the age at onset was mostly similar between males and females, although there was a trend towards younger ages for males in disorders due to substance use or addictive behaviours (median = 4 years earlier), mood disorders (median = 2 years earlier) or schizophrenia-spectrum and primary psychotic disorders (median = 1 year earlier). Similarly, there were little differences in age at onset among studies where onset was defined according to first symptoms, first diagnosis or first hospitalisation, although there was a trend towards younger ages for first symptoms than for the first diagnosis in disorders due to substance use/addictive behaviours (median symptoms 9 years earlier), mood disorders (median 8 years earlier), anxiety and fear-related disorders (median 3 years earlier). For schizophrenia-spectrum and primary psychotic disorders, we observed a trend from symptoms to hospital admission (median a year later) to diagnosis (median another year later). There were other minor differences in disorders with fewer (<10) separate studies for sex or onset definition, for which we suggest caution as the estimations may be less accurate than others.Table
