In 13 chronic schizophrenic patients (age range: 22-61 years) with troublesome behaviour and/or dysthymia, who were on maintenance treatment with a combination of incisive neuroleptics and sedative drugs, the sedative therapy was abruptly replaced by pipamperone. Dosage was gradually increased from 80 mg/day to an optimal level of 160-320 mg/day. The patients' condition was assess by Overall's "Factor Construct Rating Scale" and a 4-item questionnaire for sleep disorders. Pipamperone proved to be very rapidly effective in patients with prominent sleep disorders and/or agitation. Improvement was also significant for various other items of the two rating scales. No pipamperone-related side-effects were observed or reported.