one must understand and distinguish between associations and causal relationships among many potential risk factors. A risk factor is something that has a possible role in the initiation of a disease, the progression of a disease to a further state, or in the waning of a disease (which is then a protective factor). Demographic, biological, personality, family, peer, and genetic factors, among other possible risk factors, may interact over time to influence the course of outcomes, symptoms, and behaviors. Risk factors are most useful for research when they refer to a specific phenomenon that provides a feasible point of intervention. Some factors may be related exclusively to initiation; others may be related only to subsequent progression into problem or pathological gambling. Although important, such etiological distinctions have been rarely made in the relatively recent and limited literature on pathological and problem gambling.

The literature on posttraumatic stress disorder (PTSD) offers an analytic model for distinguishing risk factors. Breslau and Davis (1987) demonstrated that it was the original exposure to a precipitating event, and not reexposure, that led to symptoms of PTSD among Vietnam veterans. In another study, Breslau and colleagues (1991), in an examination of young urban adults, identified risk factors for exposure to traumatic events (i.e., low education levels, being male, early conduct problems, and extraversion) that were distinct from risk factors for the actual disorder once exposed (i.e., early separation from parents, neuroticism, preexisting anxiety or depression). Distinguishing risk factors is crucial in etiology research, as is identifying common risk factors for the progression of an illness. In the study just described, a family history of a psychiatric disorder or a substance abuse problem was identified as a common risk factor for exposure to traumatic events and acquiring PTSD.

Equally important to consider in etiological research on pathological and problem gambling is which factors for chronic, long-term gambling are unique to this disorder and not just predictors of excessive deviant behavior of all kinds. Again, the PTSD literature provides a template for research on pathological