Low body weight in male children and adolescents with schizoid personality disorder or Asperger's disorder.

This study explored the hypothesis that body weight is reduced in male children and adolescents with schizoid personality disorder or Asperger's disorder. The body weights of 33 consecutively admitted male subjects with one of these disorders were retrospectively assessed with percentiles for the body mass index (BMI). The mean percentile (+/- SD) for the BMI was 31.6 +/- 27.6 and differed significantly from the expected value of 50 (P<0.001). Ten subjects had a BMI of < or = 10th age percentile. Post hoc comparisons revealed that BMI percentiles were (a) reduced to a similar extent in patients with schizoid personality disorder and Asperger's disorder and (b) reduced to a greater extent in patients with abnormal eating behaviour. During childhood and adolescence both diagnoses are associated with an increased risk of being underweight. Population-based BMI percentiles are useful for detecting associations between specific psychopathological syndromes and body weight.