Reactivity Following Losses and Wins and Risky Decision Making in Bipolar and Healthy Young Adults: Relations with Clinical Heterogeneity and Neuroanatomical Variation

Bipolar disorder affects 4.4% of individuals in the United States during their lifetime. Diagnosis is difficult which limits prevention, early detection, and intervention because of overlapping symptoms (e.g. similar symptoms in depression, schizophrenia) and disease heterogeneity (e.g. variation in cognitive deficits and clinical course). Prior research has pointed to the idea of neurobiologically defined subgroups determined by phenotypic markers such as risky decision making and sensitivity to reward/punishment. Identification of markers may improve prediction and early identification of detrimental outcomes and differences in clinical course. Increased risky decision making is suggested to increase risk for detrimental outcomes in healthy populations (e.g. increase risk for alcohol use problems, nicotine use, suicide-related behavior). The Iowa Gambling Task (IGT) is a card game used to measure risky decision making (selecting cards from riskier decks compared to safer decks). The dorsolateral and ventromedial prefrontal cortex, ventral striatum and anterior cingulate have been implicated to contribute to altered performance on the IGT. The purpose of this study was to investigate risky decision making and reactivity following loses/wins on the IGT as behavioral markers for bipolar disorder disease heterogeneity (both clinical and neuroanatomical variation). This was done by collecting IGT and MRI data which was correlated to the following clinical outcomes: suicide, substance abuse, alcohol abuse, sensitivity to reward/punishment, sensation seeking, impulsivity, and rejection sensitivity. We found that bipolar subjects have a longer reaction time after selecting a loss card compared to healthy controls. Within the bipolar population, we found a shorter reaction time following a loss was associated with decreased sensitivity to punishment, increased total drinks per heaviest drinking weeks, and past history of substance abuse. Decreased safe risky score (more risky choices) and lower net money was associated with increased sensitivity to reward, consistent with past literature suggesting that increased sensitivity to reward is associated with negative outcomes. Additionally, we found regional differences in gray matter volume associated with reaction time following a loss and safe risky scores are also associated with altered rejection sensitivity and marijuana use in bipolar disorder. More work is still needed to understand neuroanatomical variation and relationship with IGT/clinical heterogeneity.Dell Medical Schoo