The interaction of reinforcement sensitivity and life events in the prediction of anhedonic depression and mixed anxiety-depression symptoms

This study examined the relationship between reinforcement sensitivity theory (RST), life stress, and internalizing symptoms. Generally, low sensitivity of the behavioral approach system (BAS) predicts depression whereas high sensitivity of the behavioral inhibition system (BIS) predicts anxiety and depression. However, few studies have examined how RST variables interact with life stress to predict these symptoms. It was hypothesized that higher BIS sensitivity would predict greater anxious arousal; lower BAS sensitivity and higher BIS sensitivity would predict greater anhedonic depression as predicted by the joint subsystems hypothesis (JSH); and low BAS, high BIS, and high life stress would interact to predict anhedonic depression symptoms whereas high BIS with high life stress would predict anxious symptoms. A sample of 285 undergraduates completed measures of RST, life stress, and internalizing symptoms. Greater BIS sensitivity predicted mixed anxiety-depression and anhedonic depressed symptoms, lower BAS predicted anhedonic depression symptoms, and life events predicted mixed anxiety-depression. Three-way interactions indicated that for high life stress, BIS predicted both types of symptoms. For low life stress, low BAS and high BIS predicted anhedonic depression whereas high BIS and high BAS predicted mixed anxiety-depression. The implications of these findings are discussed in terms of the JSH.