The aim of this chapter is to consider the question — Do prevention and early intervention programs for the major internalising (anxiety and depression) and externalising (behavioural) disorders in young people hold promise for reducing the incidence of substance use disorders in the community? The question is important for several reasons. First, substance use disorders represent a substantial health problem in society with significant economic and human costs. Second, traditional prevention strategies that focus on psychoeducation regarding the dangers of using alcohol and drugs, or teaching youth skills for resisting pressure to use substances, have generally been unsuccessful. Third, there is considerable evidence suggesting comorbidity between internalising and externalising problems and substance use problems (see Chapter 3). Therefore, it would seem plausible that early intervention and prevention strategies for internalising and externalising problems could impact on the incidence of substance use disorders. Addressing comorbid conditions is a vital concern for health professionals as comorbidity often means that the course of the problems is more chronic and severe compared with single disorders, and it can create more substantial social and occupational decline for the diagnosed person.

The current body of literature on the prevention of substance use problems suggests that in order to advance understanding in this area, researchers must adopt a risk-focused approach. That is, we need to specify aetiological theories of substance use disorders based on risk factor research, and design and evaluate interventions that reduce or eliminate the identified risk factors (Gorman, 1996; Hawkins, Catalano, & Miller, 1992). The central tenet of this paper is that the presence of anxiety, depression, or behavioural problems or their risk factors in young people can represent risk factors for the development of later substance use problems. Thus, it is predicted that these disorders and associated risk factors can be targeted for prevention of substance use disorders. The current paper will address this issue by a) outlining risk factors for substance use problems, b) highlighting links between risk factors for substance use disorders and other mental disorders in young people, c) addressing comorbidity between substance use disorders and other mental disorders, d) discussing the implications of risk factor approaches for prevention of substance use disorders, and e) outlining current early intervention programs for anxiety, depression, and behavioural disorders that could potentially reduce the incidence of substance use disorders.

It is noted that adopting a risk-reduction approach to substance abuse prevention is likely to require the development and evaluation of multiple interventions, rather than one generic intervention that can be successful in reducing the incidence of substance use problems for all people all of the time (Catalano, Kosterman, Hawkins, & Newcomb, 1996). Thus, while the current paper focuses on interventions that target anxiety, depression, and behavioural problems, it does not disregard the potential success of other types of prevention programs that address empirically supported risk factors.

Substance use disorders will be used here to refer to both alcohol and drug disorders unless the point under discussion refers to one or the other specifically. Internalising disorders will be used to refer to the cluster of disorders characterised by negative affectivity, including the depressive disorders of Major Depressive Episode and Dysthymia, and the anxiety disorders of Generalised Anxiety Disorder, Panic Disorder, Agoraphobia, Social and Simple Phobias, Obsessive Compulsive Disorder, and Post-traumatic Stress Disorder. The depressive and anxiety disorders show high rates of comorbidity within and between each other, leading many researchers and clinicians to consider them as a general class (e.g., negative affectivity, neuroticism, or internalising disorders). Externalising disorders will be used to refer to the cluster of disorders characterised by behavioural problems including Oppositional Defiant Disorder, Conduct Disorder, and Attention Deficit Hyperactivity Disorder. A range of other behavioural problems may also be included within the term externalising disorders. Generally these refer to historical variations in terminology or diagnosis, or themselves contain other variants on the above diagnoses. For example, externalising disorders would also include antisocial behaviour, delinquency, and aggressive behaviour.

Much of the research reviewed in this area has used samples with subclinical problems rather than diagnosed disorders. For example, many studies of externalising disorders have used broad samples of children referred for disruptive behaviour problems, or children selected from non-referred samples who were found to have disruptive behaviour problems on the basis of a screening measure. Given this and the inherent arbitrariness of the cut-off between problem and disorder, the term 'disorder' will be used loosely to refer to a broad range of identified problems (including explicitly diagnosed disorders) unless otherwise specified.Top of page