Efficacy and safety of clozapine in treatment-resistant psychotic patients with DiGeorge syndrome (22q11.2 deletion syndrome): a case series.

Neuropsychiatric disorders are common manifestations in 22q11.2 deletion syndrome (22q11.2DS-DiGeorge Syndrome). Although many patients with 22q11.2DS receive antipsychotic treatment for psychotic disorders, little is known about the safety and tolerability of antipsychotics in 22q11.2DS and resistant psychosis. The aim of this case series is to describe the effectiveness as well as safety and tolerability profile coming from the real-world observation of three clinical cases affected by 22q11.2DS and treatment-resistant psychosis. We administered the following tests: the Columbia Suicide Severity Rating Scale, the Hamilton Rating Scale for Anxiety, the Positive and Negative Severity Scale, the Clinical Global Impression-Severity Scale, the Yale-Brown Obsessive-Compulsive Scale, the Beck Depression Inventory and the Beck Hopelessness Scale. All these questionnaires were administered at the first visit (T0), and then 3 (T1) 6 (T2) and 12 months after (T3). We observed a clinical improvement that remained stable at 12 months. Furthermore, in our patients, the clinical effectiveness was achieved with a very low dose of clozapine (<150 mg/day) concerning the standard dose used in idiopathic schizophrenia (>300 mg/day to 600 mg/day).