Ninety-one individuals from the original child cohort met criteria but one had died (cause unknown). Of these, 82 were
traced and contacted, 12 did not respond and 10 (two of whom considered they no longer had autism) declined to participate. In total, 60 individuals (49 males, 11 females; 67% of the eligible sample still alive) agreed to participate. There were no significant differences between non/participants with respect to childhood nonverbal IQ or language level, or ADI total scores at diagnostic confirmation.