In our clinical practice, we have had good experiences with venlafaxine in the treatment of self-injurious behavior (SIB) and attention deficit/hyperactivity disorders (ADHD)-like symptoms in patients with pervasive developmental disorders (PDD), and we report here three cases of possible therapeutic response: (A) a 17-year-old boy with autism and severe behavioral symptoms, including aggression toward self or property, SIB and hyperactivity, who appeared to respond to low-dose venlafaxine (18.75 mg/day); (B) a 23-year-old woman with autism hyperactivity who appeared to respond to low-dose venlafaxine (18.75 mg/day); (C) a 17-year-old girl with autism hyperactivity who appeared to respond to low-dose venlafaxine (18.75 mg/day). Follow-ups occurred respectively 18, 36 and 6 months after treatment initiation, making it possible to observe the stability of the clinical improvement in these cases.