Abstract
Negative symptoms are often enduring and lead to poor functional outcomes in individuals with schizophrenia. The cognitive model of negative symptoms proposes that low expectancies of success contribute to the development and maintenance of negative symptoms; however, longitudinal investigations assessing these beliefs and negative symptoms are needed. The current study examined whether an individual's baseline expectancies of success - one's beliefs about future success and goal attainment - predicted negative symptoms reduction over 18 months in individuals with schizophrenia-spectrum disorders (n=118). Data were collected at baseline, 9 months, and 18 months as part of a randomized controlled trial of Illness Management and Recovery. A mixed effects regression analysis revealed a significant reduction in negative symptoms over time, with a significant interaction effect between time and baseline expectancies of success. After controlling for baseline negative symptoms, demographic variables, and treatment conditions, those with high and moderate baseline expectancies of success evidenced a significant reduction in negative symptoms at 18 months, while those with low baseline expectancies of success did not evidence reduced negative symptoms. Findings support the cognitive model of negative symptoms and suggest that expectancies of success may be a useful treatment target for interventions aimed at reducing negative symptoms.