An intriguing result of the study was the interplay of psychological and neurophysiological measures in predicting obesity. As shown in Model 3 and mentioned above, stimulant dependence symptoms were negatively associated with obesity via a simple direct path. But another component of the variance in stimulant dependence symptoms was subsumed within the variance it shares with conduct problems, depression symptoms, and impatience (i.e., CNVamplitude) and associated with obesity via an alternate indirect path. The connection of obesity to stimulant dependence and to a known risk factor for stimulant and other substance dependence (i.e., conduct problems; Hodgins, Tiihonen, & Ross, 2005; Modestin, Matutat, & Wurmle, 2001; Robins, 1991; Rowe, Sullivan, Mulder, & Joyce, 1996) via this other path is consistent with recent hypotheses proposed by Volkow and Wise (2005) and Ehlers and Wilhelmsen (2007) wherein substance dependence and obesity are viewed as outcomes of a similar genetic diathesis.
