Mervis, Joshua2021-10-132021-10-132021-08https://hdl.handle.net/11299/224990University of Minnesota Ph.D. dissertation. 2021. Major: Psychology. Advisor: Angus MacDonald. 1 computer file (PDF); vii, 161 pages.The studies presented here examine three domains of insight along the psychosis spectrum. The first domain is clinical insight, which is the awareness of a mental illness, its impacts, and the need to ameliorate those impacts. The second is cognitive insight, which is understanding thought processes as fallible. The third is introspective accuracy. which refers to domain-specific self-assessment. The first study investigates introspective accuracy for substance use in the context of a year of treatment for people with first episodes of psychosis. The second study uses geometric dimension reduction to examine cognitive and clinical insight together and their relationship to forms of cognition in people with prolonged psychosis. Finally, the third study uses probabilistic dimension reduction as a tool for exploratory translational research on psychotic-like experiences, cannabis use, and insight in the general population. Results for insight across all three studies indicated one paradoxical effect, one effect for a form of cognition, and a mixed finding. The first study found a paradoxical effect for IA, such that those who had poor IA that were overconfident had greater symptom remission midway through treatment for an FEP. The second study presented here found that the combination of poorer clinical and cognitive insight accompanied poorer metacognition, whereas better clinical insight accompanied better metacognition regardless of cognitive insight. The third study had mixed results that show poorer insight sometimes accompanies greater symptoms, which is consistent with the findings of our review even though it did not cover general population samples. Overall, all three studies presented here add to the existing evidence for positive, paradoxical, and mixed findings for the relationships between insight and other constructs of clinical interest. Finally, future directions in terms of conceptual and treatment implications are discussed.enclinical insightcognitive insightintrospective accuracymetacognitionpsychosissubstance useThesis or Dissertation