Stereotypic movement disorder symptoms include: repetitive, seemingly driven, and nonfunctional motor behavior (e.g., hand shaking or waving, body rocking, head banging, mouthing of objects, self-biting, picking at skin or bodily orifices, hitting own body).

The behavior markedly interferes with normal activities or results in self-inflicted bodily injury that requires medical treatment (or would result in an injury if preventive measures were not used).

If mental retardation is present, the stereotypic or self-injurious behavior is of sufficient severity to become a focus of treatment.

The behavior is not better accounted for by a compulsion (as in obsessive-compulsive disorder), a tic (as in tic disorder), a stereotypy that is part of a pervasive developmental disorder, or hair pulling (as in trichotillomania).

The behavior is not due to the direct physiological effects of a substance or a general medical condition.

The behavior persists for 4 weeks or longer.