ANOREXIA NERVOSA (AN) often coexists with pervasive developmental disorders (PDD). The standard psychological therapy for AN frequently fails in PDD, suggesting a different psychopathological background.1 We describe successful olanzapine treatment of AN in a patient with pervasive developmental disorder not otherwise specified (PDD-NOS). Informed written consent was obtained.
A 17-year-old girl with a 1-year history of anorexia was referred to Sapporo Medical University Hospital. She skipped meals and ate only small amounts of rice and salad; consequently, her weight had decreased from 54.0 to 29.0 kg (151 cm in height). She repeatedly expressed excessive fear of weight gain or obesity and had been amenorrheic for 8 months. No psychotic symptoms were observed. She met the DSM-IV criteria for restricting-type AN. Initially the patient refused all treatment, but finally agreed to take only one medicine without water for her insomnia. Olanzapine, orally disintegrating tablet, was started at 2.5 mg and increased to 5 mg after 2 weeks. Approximately 6 weeks later, weight gain without adverse effects began and 5 months later her weight reached the standard (body mass index, 20.3 kg/m2). Four months later her abnormal eating habit gradually remitted.
The patient had no substantial delay in motor or language development. She exhibited difficulty with social interaction and tended to enjoy solitary activities, while she did well academically. Behavioral rigidity and a tendency to impose routines were noted. She was often preoccupied with particular books, and has an unusual sensitivity to noises but the criteria were not met for a specific PDD. These findings led us to diagnose PDD-NOS according to the DSM-IV definition.
Previous studies have used olanzapine to treat AN.2 Because weight gain is a common adverse effect of olanzapine, it is unsurprising that olanzapine restores weight in anorexic subjects. Despite many studies, the mechanism underlying olanzapine-induced weight gain remains unclear.
Many anorexic patients have comorbid PDD. AN and PDD share obsessive and compulsive traits.1 PDD involves the triad of impaired social interaction, communication, and imagination, with a rigid, repetitive pattern of behavior. The objects of preoccupation could be food, calorie intake, or weight. Hypersensitivity to smell or taste might limit the choice of meals. These symptoms could cause abnormal eating behavior. The DSM-IV symptom-based diagnosis might produce a heterogeneous group of AN patients including some with PDD. Although all patients with AN verbalize intense fear of weight gain or obesity, those with comorbid PDD might have a different underlying psychopathology compared to conventional AN.1 Previous studies have indicated the efficacy of olanzapine in weight restoration in some anorexic patients.2 The result might reflect the fact that use of olanzapine is restricted to AN with PDD. Further clinical studies on subgroups of AN in the presence and absence of comorbid PDD are recommended.