Unique to the design of this study was the ability to examine subgroups of patients from prospectively collected daily diary measures. Daily diary measures are not new to the addiction field and have been used to monitor outcomes and assess the relationship between stress and alcohol use. Daily measures of affect were associated with alcohol consumption in an outpatient treatment study for heavy non-dependent drinkers (Armeli et al., 2000). However, daily measures of craving were not reported in this study. A similar study in heavy drinkers found stress to be inversely correlated with alcohol use (Helzer et al., 2006). Neither of these studies used daily data to categorize different patterns of craving. Patterns of drinking have been studied in a group of 171 light to heavy drinkers (Schroder and Perrine, 2007). Results in these non-dependent individuals did show four distinct clusters of individuals with the largest group showing no relationship between mood and alcohol use, but there were clusters showing drinking in combination with positive mood states and a cluster of drinking with negative mood states. Although results from these published reports may not apply to alcohol-dependent individuals, the methodology provides a mechanism for understanding the heterogeneity among individuals.
