This is a case study of a 27-year-old man with co-morbid congenital communicating hydrocephalus and epilepsy. The patient had multiple hospitalizations in psychiatric clinics due to serious domestic violence caused by compulsive buying demands. Impaired social interaction skills, diminished judgment, planning, insight and temporal organization difficulties were also present and the diagnosis of organic personality disorder was given.

The patient was treated with 1.5 g valproc acid for epilepsy and for the behavioural difficulties multiple antipsychotics, benzodiazepines, SSRI's and beta-blockers were administrated, without major benefits. Due to serious aggression and impulsive behaviour, it was administrated memantine 20 mg/day according to NMDA receptor antagonist hypothesis and gradually reduced the benzodiazepines and SSRI's.

A significant decrease in the average score of the Barratt Impulsiveness Scale (BIS-11) and to violence incidences was observed. Also, social interaction skills were improved and a slight improvement at patient's judgment was observed.

The patient had good tolerance during the treatment and no side effect was reported. It is the first scientific report on memantine effectiveness in this patient group. Further research is needed.