Stereotypic Movement Disorder involves repetitive, almost rhythmic movements with onset by age 3.

• A. Delusions and hallucinations
• B. Social withdrawal
• C. Repeated, rhythmic movements starting by age 3
• D. Motor tics only

Answer: (C)

Stereotypic Movement Disorder is defined by repetitive, nonfunctional motor behaviors that are stereotyped and often rhythmic, with onset in early childhood, typically before age three. That description matches exactly: repeated, rhythmic movements starting by age three.

Delusions and hallucinations would suggest a psychotic process, not a motor stereotype. Social withdrawal is a nonspecific symptom that can occur in multiple conditions and doesn’t define this disorder. Motor tics characterize tic disorders like Tourette’s and are usually brief, irregular, and not the same as the sustained, rhythmic, repetitive movements seen in SMD.