A naturalistic open-label study of mirtazapine in autistic and other pervasive developmental disorders

Objective: The aim of this study was to conduct a naturalistic, open-label examination of the efficacy and tolerability of mirtazapine (a medication w ith both serotonergic and noradrenergic properties) in the treatment of ass ociated symptoms of autism and other pervasive developmental disorders (PDD s). Methods: Twenty-six subjects (5 females, 21 males; ages 3.8 to 23.5 years; mean age 10.1 +/- 4.8 years) with PDDs (20 with autistic disorder, 1 with A sperger's disorder, 1 with Rett's disorder, and 4 with PDDs not otherwise s pecified were treated with open-label mirtazapine (dose range, 7.5-45 mg da ily; mean 30.3 +/- 12.6 mg daily). Twenty had comorbid mental retardation, and 17 were taking concomitant psychotropic medications. At endpoint, subje cts' primary caregivers were interviewed using the Clinical Global Impressi ons (CGI) scale, the Aberrant Behavior Checklist, and a side-effect checkli st. Results: Twenty-five of 26 subjects completed at least 4 weeks of treatment (mean 150 +/- 103 days). Nine of 26 subjects (34.6%) were judged responder s ("much improved" or "very much improved" on the CGI) based on improvement in a variety of symptoms including aggression, self-injury, irritability, hyperactivity, anxiety, depression, and insomnia. Mirtazapine did not impro ve core symptoms of social or communication impairment. Adverse effects wer e minimal and included increased appetite, irritability, and transient seda tion. Conclusions: Mirtazapine was well tolerated but showed only modest effectiv eness for treating the associated symptoms of autistic disorder and other P DDs.