Assessment of Risk for Psychosis

Abstract

The last few decades have seen a radical change in perspectives on research and treatment of schizophrenia and other psychotic disorders. Advances in treatment, neuroimaging, and biomarker research ushered in a new optimism and, not unrelated, increasing focus on early stages of illness with the goal of better understanding mechanisms and intervening before they cause lifelong impairment or disability. A watershed in this new generation has been the movement to identify and treat those potentially in the prepsychotic or high-risk stage of illness, now an entire field of its own, given the alluring potential for preventing illness altogether. However, prevention of psychiatric illness, particularly psychotic disorders, has proven to be a complicated endeavor because no clear, specific, or perfectly predictive warning signs or syndromes have been identified. Instead, researchers and clinicians are left to prospectively estimate latent risk based on the presence of signs, symptoms, or syndromes that research has found to be associated with psychosis. This has been done by examining differences between cohorts with and without psychosis, via retrospective research, by studying family members of those with psychosis, and through longitudinal studies that identify predictors of psychosis onset in high-risk cohorts. Subsequently, when these markers are identified in a new individual, they are deemed to be at elevated risk for that condition, and decisions must be made about whether the estimated risk is high enough to warrant some early intervention. An intense focus of research over the past roughly two decades has been on identifying specific demographics, historical factors, clinical syndromes, biomarkers, and algorithms that combine the markers most predictive of subsequent psychosis in order to apply them prospectively in clinical care. This chapter will briefly summarize current methods and models for assessing known markers of psychosis risk, discuss why clinical syndrome identification—attenuated psychosis syndromes—are currently the predominant method for identifying risk, and present vignettes that characterize different prototypical APSs.