A decrease can be in perceived risk of use.Logical formLearned from2 sentences. Increases can be in perceived risk of (cigarette use).Logical formLearned from2 sentences. Declines can be in perceived risk of (cocaine use).Logical formLearned from2 sentences. A serostatus can be perceived.Logical formLearned from2 sentences. Perceived risk can be constituted-of-or-filled-with (substance use).Logical formLearned from2 sentences. (Program benefits) can be perceived.Logical formLearned from2 sentences. A msv can be perceived.Logical formLearned from2 sentences. (Group norms) can be perceived.Logical formLearned from2 sentences. An (incentive value) can be perceived.Logical formLearned from2 sentences. Barriers to collaboration can be perceived.Logical formLearned from2 sentences. A perceived risk of use may increase among 8th-graders.Logical formLearned from2 sentences. Perceived risk of harm may decrease for a year.Logical formLearned from2 sentences. Changes can be in perceived risk.Logical formLearned from2 sentences. Perceived risk may be assessed.Logical formLearned from2 sentences. An availability of medications may affect perceived risk of (drug use).Logical formLearned from2 sentences.