Recognition came twenty years after, with epidemiological studies showing that approximately 20% of adults with BD already had symptoms in childhood or adolescence. Nevertheless, onset before age 10 was thought to be rare, below 0.5% of the cases. During the second half of the century misdiagnosis with schizophrenia was not rare in the non-adult population due to common co-occurrence of psychosis and mania, this issue diminishing with an increased following of the DSM criteria in the last part of the 20th century.[1][20]