Clinical efficacy, safety and tolerability of quetiapine in the treatment of 23 hospitalized psychotic adolescents were evaluated retrospectively. Twelve patients were changed to quetiapine from another antipsychotic medication during their hospital stay. In these patients, CGI-S improved from 4.75+/-0.87 to 2.92+/-0.67 (observation period 3.7+/-1.6 months). The most common adverse events were transient tachycardia and sedation. Mild EPS occurred only in one patient under quetiapine monotherapy. Transaminase increases more than threefold above norm were observed in two patients. fT4 values were slightly below the norm in 67% of the cases. In 11 patients, quetiapine was initiated using a rapid titration schedule with high dosages in the acute phase. Receiving a mean maximum daily dose of 927+/-300 mg, CGI-S improved from 6.00+/-0.63 to 3.18+/-1.25 (observation period 2.9+/-1.8 months). Severe adverse events did not occur. Besides applying lorazepam temporarily in nine of the 11 patients, antipsychotic co-medication was not necessary in this group. In line with other studies, quetiapine may be considered as an effective treatment for adolescents with a severe psychotic disorder showing a favourable side-effect profile. Our preliminary data suggest that a rapid initiation with high doses could be a promising approach in acute psychotic adolescents.