In June 2004, aripiprazole was marketed as a second-generation antipsychotic with an entire new mechanism of action. The objective of this descriptive study is to examine the day-to-day prescriptions of aripiprazole to an unselected population of psychiatric in-patients. From 1 February to 1 May 2006, present and former in-patients treated with aripiprazole were identified. Prescriptions of aripiprazole and psychoactive comedication were collected retrospectively from the patient records. Seventy-one patients, mainly schizophrenic, received aripiprazole 2.5 to 55 mg/day for median 350 days. The median average exposure was 18.9 mg/day (range 2.5-45 mg/day) and exceeded 15 and 30 mg/day in 63% and 4.2% of the patients, respectively. Generally, aripiprazole was either added to the existing antipsychotic treatment or replaced other antipsychotics; only 17% of the patients were treatment-naïve. In 25% aripiprazole, monotherapy was commenced whereas aripiprazole-antipsychotic combinations were initially prescribed in 75%. Overall, 85% of the patients received periods of antipsychotic polypharmacy and aripiprazole was combined with 17 different antipsychotics. Each patient received median three (range 0-8) psychoactive drugs parallel with aripiprazole. This study demonstrates reality in psychopharmacology and quote aripiprazole as example. In day-to-day practice, aripiprazole is used as part of highly individualized regimens comprising polypharmacy and excessive dosing. Although theoretically appropriate for some patients, this approach also implies conducting unblinded and uncontrolled mini-experiments. Sparse evidence supports this practice and effectiveness studies of aripiprazole that takes into account the true complexity of clinical prescribing are urgently needed.