“…Consequently, many drug and alcohol treatments are explicitly designed to target and improve self-efficacy (Witkiewitz & Marlatt, 2004). Broad support for the role of self-efficacy as a determinant of positive treatment outcome has been found in alcohol-and drug-dependent patients (Allsop, Saunders, & Phillips, 2000;Goldbeck, Myatt, & Aitchison, 1997;Miller & Longabaugh, 2003;Rychtarik, Prue, Rapp, & King, 1992;Stephens, Wertz, & Roffman, 1993). For example, Ilgen, McKellar, and Tiet (2005) compared measures of self-efficacy to other measures of alcohol use and psychosocial functioning; high self-efficacy was the single strongest predictor of abstinence from drug and alcohol use 1 year after treatment.…”