Background: As part of a broader series of studies on unwanted repetitive behaviors, DSM-IV stereotypic movement disorder (SMD) was examined in an intellectually normal population. Repetitive nonfunctional behaviors, or stereotypies, are expressed during early normal development but have not been described in adults without severe psychiatric or intellectual impairment.
Method: Lifetime and current psychiatric Axis I diagnoses were determined by structured and clinical interviews in subjects who responded to a newspaper advertisement that specifically mentioned rocking and head banging.
Results: Of 52 potential subjects who were screened by telephone, 32 had been previously diagnosed with an Axis I psychiatric disorder, which presumably accounted for the repetitive behavior, or were otherwise excluded. Of 20 who were interviewed in person, 12 met DSM-IV criteria for SMD; rocking or thumb sucking was present in 8 of these 12. Four of 8 rockers had a first-degree relative who had a lifetime history of a similar repetitive behavior. A lifetime history of an affective or anxiety disorder was found for 11 of 12 SMD subjects.
Conclusion: DSM-IV stereotypic movement disorder can be diagnosed in intellectually normal individuals. Although sampling bias was probable, prominent stereotypies in individuals meeting the DSM-IV criteria for stereotypic movement disorder, which are narrower than the DSM-III-R criteria for stereotypy/habit disorder, seem likely to include rocking and thumb sucking. The likelihood of persistence of these behaviors, which are developmentally appropriate in infancy, may be enhanced by comorbidity with anxiety or affective disorders.