The 22q11.2 deletion syndrome (22q11DS) is one of the most common microdeletion syndrome with a highly variable phenotype comprising among others endocrine dysfunctions and an array of psychopathological features including schizophrenia-like psychotic symptoms.

Studying the efficacy of antipsychotics in 22q11DS-related psychoses.

Review of the literature and systematic inventarisation of treatment history and efficacy of antipsychotics in 28 genetically-proven 22q11DS-patients.

Extensive neuropsychiatric and cognitive examination as well as documentation of medical conditions, psychiatric diagnoses and previous and actual psychotropic medications.

Apart from scarce case reports, no systematic reports were found on effectiveness of antipsychotics. History of the presently included patients showed an array of psychiatric diagnoses addressed with a multitude of psychotropics. In accordance with the 22q11DS phenotype, their psychopathological profile was characterized mainly by psychotic features with anxieties and mood instability. In two patients a neurodegenerative phenotype was present, compatible with early-onset Parkinson disease (PD).

Nearly all patients had been treated with more than one antipsychotic, frequently in combination with an antidepressant. In none, any effect of conventional antipsychotics, including risperidone, was recorded. All patients, except those with PD, were treated with an atypical antipsychotic and, dependent on the presence of mood instability, valproic acid was added. In a significant number of patients this regimen resulted in long-term remission with either clozapine or quetiapine in relatively low dose.

Dependent on individual tolerance, psychoses in 22q11DS-patients are preferentially treated with quetiapine or clozapine accompanied by contextual psychological measures.