Multiple-complex Developmental Disorder (McDD) is a developmental disorder characterized by peculiar clinical features: affective dysregulation (anxiety, panic and aggressivity), impairment of social behaviour and hypersensitivity, impaired cognitive processing. McDD is usually included within the Pervasive Developmental Disorders not otherwise specified (PDD NOS) (Cohen et al. 1986; Towbin et al. 1993). Aripiprazole is a new atypical antipsychotic drug. Efficacy of aripiprazole in children and adolescents is supported by some studies (Findling et al. 2007, Wink at al 2010; Kim et al 2010).

The aim of our study is to describe the efficacy and safety of aripiprazole in 4 children with Multiple-complex Developmental Disorder.

Mean dosage of aripiprazole was 5 mg/day. Response was evaluated by clinical assessment and by Clinical Global Impressions Scale-Severity, Clinical Global Impressions Scale- Improvement, Children's Global Assessment Scale (CGAS) and by Brief Psychiatric Rating Scale. This assessment was administered at baseline, and at weeks 4, 12 and 24.

A significant reduction of social impairments, thought disorders and affective dysregulation was observed. Drug therapy was well tolerated, even though children complained of mild and transient nausea and somnolence.

To date there are only a few reports on the use of aripiprazole in McDD patients. The present case series suggest that aripiprazole may be effective and well tolerated in McDD patients.