The Longitudinal Impact of Intrinsic Motivation on Alcohol Use Severity in Schizophrenia and Its Patterns in Men and Women

Background and Purpose:Co-occurring substance use disorders (SUDs) are common in adults with schizophrenia, affecting nearly 50%, and complicating its consequences, leading to high hospitalization rates, homelessness, and infectious diseases. Such consequences not only produce poor outcomes for those with these conditions but also place considerable burdens on society. While these consequences often stem from alcohol misuse, this population has remained difficult to engage in treatment and tends to make slow progress. These challenges signal a need for identifying the factors contributing to the slow recovery rates in this population. Deficits in intrinsic motivation may contribute to these challenges such that low levels reduce the capacity of such adults to perceive that abstinence will have a positive impact on recovery. Since women begin alcohol use at a later age and have better outcomes than men, women with high intrinsic motivation may recover from alcohol use severity at faster rates. For a sample of adults with schizophrenia and comorbid SUDs, we examined the impact of intrinsic motivation on alcohol use severity over 1-year and its patterns in men and women.

Methods: Researchers using the Alcohol Use Scale interviewed men (n = 450) and women (n = 86) with schizophrenia and comorbid SUDs at baseline, 6-months, and 1-year for the Clinical Antipsychotic Trials of Intervention Effectiveness. Intrinsic motivation was measured by the sum of three items (purpose, curiosity, and motivation) from the Quality of Life Scale. Growth curve models examined the longitudinal impact of intrinsic motivation on alcohol use severity recovery in the overall sample and in subsamples of men and women.        

Results: Participants exhibited, on average, recovery from alcohol use severity over 1-year (p < .001). At baseline, participants with low intrinsic motivation presented greater alcohol use severity compared to those with high intrinsic motivation, F(1, 529) = 9.07, p = .002. Over 1-year, those with high intrinsic motivation showed faster recovery from alcohol use severity than those with low intrinsic motivation, F(1, 529) = 4.47, p =.034. While no moderating effects of gender on the longitudinal association between intrinsic motivation and alcohol use severity were observed (p = .200), these effects were then examined in men and women. Men with high intrinsic motivation showed faster recovery from alcohol use severity than those with low intrinsic motivation, F(1, 445) = 5.51, p = .019, and no differences were observed between intrinsic motivation and alcohol use severity in women, F(1, 76) = 0.33, p= .556.

Conclusions and Implications: Participants experienced recovery from alcohol use severity over 1-year, but those with low intrinsic motivation had more severe alcohol use severity, and recovered at slower rates. Our results suggest high intrinsic motivation may help improve alcohol use severity recovery rates for men, but additional strategies may be needed to improve the motivational levels and alcohol use severity outcomes of women. Our findings underscore the need for social workers to adapt motivational interventions to the needs of men and women with schizophrenia, paying particular attention to alcohol use severity and its impact on recovery.