The literature highlights a high prevalence of problem behaviours in people with Pervasive Developmental Disorders (PDD). Some recent studies refer to the pathogenic contribution of those organic conditions that include pain. People with PDD have difficulties in the functional expression of pain and tend to convert it into abnormal behaviour. Though this dynamics is not completely clarified, evidence support pain to be a prominent variable. However, pain is widely neglected in psychiatric diagnostic procedures of people with PDD.
The present paper describes 3 cases with Autism and 1 with PDD NOS, who were admitted in a psychiatric ward because of severe problem behaviours. The causes of these problem behaviours seemed to be referable to different physical conditions that could possibly affect the behavioural manifestation of pain, i.e., frontal glioma, auditory hyperesthesia, lobar pneumonia, and coprostasis.
The assessment of pain should be considered a fundamental procedure of the psychiatric practice with people who have a PDD or an intellectual disability.