['We previously published findings from our clinical trial comparing treatment outcomes for substance-dependent veterans with co-occurring depression who received Integrated Cognitive Behavioral Therapy (ICBT) or Twelve-Step Facilitation (TSF) Therapy.', 'This study is a secondary analysis that examined whether neuropsychological functioning at baseline moderated substance use and depression outcomes in ICBT relative to TSF.', 'This study was a randomized clinical trial in which 164 veterans with major depressive disorder and comorbid alcohol, cannabinol, and/or stimulant dependence were randomly assigned to either ICBT or TSF group therapy. A comprehensive neuropsychological test battery was administered at baseline.', 'Contrary to our hypothesis, participants with poor neuropsychological functioning had better substance use outcome in ICBT than in TSF, whereas participants with good neuropsychological functioning had comparable substance use outcomes in TSF and ICBT by 18-month follow-up. Depression outcomes, in contrast, were not moderated by neuropsychological functioning by 18-month follow-up.'] Do neuropsychological functioning and outcomes of treatment for co-occurring depression and substance use disorders?