Functional analyses were conducted during a double-blind, placebo-controlled study of the atypical antipsychotic medication risperidone with 13 individuals. Risperidone was effective in reducing destructive behavior (compared to placebo) for 10 participants. For 7 of these responders, an undifferentiated pattern of responding occurred across their baseline functional analysis conditions (i.e., a similar rate of responding across conditions), and risperidone treatment produced nonspecific reductions of their destructive behavior across functional analysis conditions. For the remaining 3 responders, a differentiated pattern of responding occurred across their baseline functional analysis conditions (i.e., an elevated rate of responding occurred in a specific condition), and risperidone treatment produced function-specific reductions of their destructive behavior.