Introduction to the special issue on the impact of childhood psychopathology interventions on subsequent substance abuse: pieces of the puzzle.

Studies of adolescents and adults have reported high levels of co-occurrence of substance abuse with other psychiatric disorders, suggesting influence between the conditions. The comorbidity seems complex and variable, indicating that there may be more than I type of association between the comorbid disorders. When occurring in childhood. some of the frequently comorbid psychopathologies typically precede later drug and alcohol abuse and may have implications for substance abuse prevention as early risk indicators and as targets for intervention. Research discussed in this article and in this special issue provides a foundation for investigating the question of whether effective treatment of childhood psychopathologies can prevent or at least mitigate substance abuse for some adolescents. Clinical, research, and policy implications are discussed.