Two adolescent groups of primary concern are young people affected by familial chemical dependency and those who are vulnerable because of life or physical stressors. The first group often presents clinicians with a confusing diagnostic picture, and accurate history-taking in the form of a three-generational genogram is essential to sort out etiological factors. Those affected by life or physical stressors are impacted by unavoidable environmental influences such as family and community problems and creative, developmental, and neurological characteristics. Subcategories of this type of at-risk adolescent include alienated, learning disabled, and gifted youth, as well as youth from dysfunctional families and environments. Adolescents in dysfunctional families may be at risk because of marital discord and divorce, while adolescents in dysfunctional environments may be at risk due to poverty and high crime neighborhoods, lack of educational or occupational opportunity, and lack of social mobility. The impact of the "violence triad" (suicide, homicide, and accident) on adolescents is discussed, and prevention efforts directed toward adolescents at risk for chemical dependency are reviewed. 47 references.