Much of the Neurocognitive Impairment in Schizophrenia is Due to Factors Other Than Schizophrenia Itself: Implications for Research and Treatment

Patients with schizophrenia perform worse on neuropsychological tasks than controls. While most experts ascribe poor performance to neurocognitive impairment, an emerging literature is identifying important nonspecific mediators of neurocognitive test performance, some of which can be accounted for in trials (eg, motivation, effort, defeatist performance beliefs, stress, anxiety, physical inactivity). Other factors are harder, if not impossible, to control when patients are compared to non-clinical participants (eg, hospitalization, medication effects, distraction due to positive symptoms). Effect sizes of neurocognitive performance differences are usually not adjusted for these confounders, and the level of neurocognitive impairment due to schizophrenia is thus likely exaggerated. We suggest some ways for researchers to account for the effects of these mediators. Secondary influences that negatively affect neurocognitive performance should not be treated as mere noise. They give important insight into causal mechanisms and may inform more effective treatments that go beyond cognitive remediation.

From neurocognition to community participation in serious mental illness: the intermediary role of dysfunctional attitudes and motivation

BackgroundEvidence for a relationship between neurocognition and functional outcome in important areas of community living is robust in serious mental illness research. Dysfunctional attitudes (defeatist performance beliefs and asocial beliefs) have been identified as intervening variables in this causal chain. This study seeks to expand upon previous research by longitudinally testing the link between neurocognition and community participation (i.e. time in community-based activity) through dysfunctional attitudes and motivation.MethodAdult outpatients with serious mental illness (N = 175) participated, completing follow-up assessments approximately 6 months after initial assessment. Path analysis tested relationships between baseline neurocognition, emotion perception, functional skills, dysfunctional attitudes, motivation, and outcome (i.e. community participation) at baseline and follow-up.ResultsPath models demonstrated two pathways to community participation. The first linked neurocognition and community participation through functional skills, defeatist performance beliefs, and motivation. A second pathway linked asocial beliefs and community participation, via a direct path passing through motivation. Model fit was excellent for models predicting overall community participation at baseline and, importantly, at follow-up.ConclusionsThe existence of multiple pathways to community participation in a longitudinal model supports the utility of multi-modal interventions for serious mental illness (i.e. treatment packages that build upon individuals’ strengths while addressing the array of obstacles to recovery) that feature dysfunctional attitudes and motivation as treatment targets.