Autistic features, personality, and adaptive behavior in males with the fragile X syndrome and no autism.

Nine males with mental retardation due to fragile X syndrome were compared to 9 males with mental retardation of other etiology. Subjects were compared on measures of personality, autistic features, and adaptive behavior. Results suggested that males with fragile X syndrome have a distinct psychological profile. In terms of DSM-III-R definitions, they had more autistic features, more schizoid features, and more schizotypal features. On measures of temperament, these males were more shy, more socially withdrawn, less energetic, and more emotional. The two groups did not differ with respect to adaptive behavior skills.