Comorbidity rates of ASD could be reliably pooled only from paediatric studies. ASD and OCD are often difficult to differentiate in young children due to an inadequately developed verbal repertoire to express experiences of obsessions, and the phenomenologically similar repetitiveness and inflexibility in behaviours (85). According to our analysis, around 6% children with OCD may have comorbid ASD. The reverse comorbidity, i.e., OCD in children with ASD, is almost double (86).
