The incidence of medical and behavioral symptoms that could occur as side effects of psychotropic medication was assessed in a sample of 30 adults with developmental disabilities. Using a retrospective chart review method, we measured symptoms in six a priori classes of potential side effects over a 2-year period. The majority of side effects involved apparent effects of the psychotropic medications on behavior, mood, or sleep. Different patterns of changes in medication prescription, in relation to recorded side effects, were observed. Overall, there was a significant positive relation between the number of potential side effects recorded and the number of psychotropic medication changes made. Our findings suggest several patterns of side effects associated with psychotropic medication use.