Impairment in delay discounting in schizophrenia and schizoaffective disorder but not primary mood disorders

Abstract

A measure of planning and impulse control, the delay-discounting (DD) task estimates the extent to which an individual decreases the perceived value of a reward as the reward is delayed. We examined cross-disorder performance between healthy controls (n = 88), individuals with bipolar disorder (n = 23), major depressive disorder (n = 43), and primary psychotic disorders (schizophrenia and schizoaffective disorder; n = 51) on the DD task (using a $10 delayed larger reward), as well as the interaction of DD scores with other symptom domains (cognition, psychosis, and affect). We found that individuals with schizophrenia and schizoaffective disorder display significantly greater rates of discounting compared to healthy controls, while individuals with a primary mood disorder do not differ from healthy controls after adjustment for IQ. Further, impairment in working memory is associated with higher discounting rates among individuals with schizophrenia and schizoaffective disorder, but cognitive dysfunction alone does not account for the extent of impairment in DD. Taken together, these results suggest an impaired ability to plan for the future and make adaptive decisions that are specific to individuals with psychotic disorders, and likely related to adverse functional outcomes. More generally, this work demonstrates the presence of variation in impulsivity across major psychiatric illnesses, supporting the use of a trans-diagnostic perspective.

A Genetic Model of Impulsivity, Vulnerability to Drug Abuse and Schizophrenia-Relevant Symptoms With Translational Potential: The Roman High- vs. Low-Avoidance Rats

“…As mentioned previously, a proactive coping style is often associated with impairments in attention and cognitive flexibility, as well as heightened impulsivity (for a review see Coppens et al, 2010). These traits have in turn been associated with schizophrenia in patients (Brown et al, 2018; Ho et al, 2018). Thus, using both psychometric impulsivity scales and the delay discounting task (a measure of action planning and impulse control in which higher rates of reward discounting, due to the preference of smaller and immediate rewards over delayed and larger ones, reflect enhanced impulsivity), it has been shown that impulsivity measures are positively associated in a consistent manner with schizophrenia, schizoaffective disorder, and schizophrenia risk in unaffected biological relatives of patients (Ahn et al, 2011; Brown et al, 2018; Ho et al, 2018).…”

“…These traits have in turn been associated with schizophrenia in patients (Brown et al, 2018; Ho et al, 2018). Thus, using both psychometric impulsivity scales and the delay discounting task (a measure of action planning and impulse control in which higher rates of reward discounting, due to the preference of smaller and immediate rewards over delayed and larger ones, reflect enhanced impulsivity), it has been shown that impulsivity measures are positively associated in a consistent manner with schizophrenia, schizoaffective disorder, and schizophrenia risk in unaffected biological relatives of patients (Ahn et al, 2011; Brown et al, 2018; Ho et al, 2018). In addition, the presence of heightened impulsivity in schizophrenia is paralleled by impairments in working memory (Ahn et al, 2011; Brown et al, 2018).…”

Temporal and Effort cost Decision-making in Healthy Individuals with Subclinical Psychotic Symptoms

“…However, this correlation was found when we considered hyperbolic parameter k (supplementary information), an aspect that deserves future investigation. These results are only partly in line with evidence that schizophrenia patients prefer more immediate rather than delayed rewards compared to healthy controls 10–13 . We should however mention that the results of the majority of the study on patients were based on the hyperbolic model and used monetary rewards.…”

“…Abnormal temporal and effort discounting of rewards characterizes several forms of psychopathology, including schizophrenia 3,9 . By and large, individuals with schizophrenia seem to choose immediate over long-term rewards more frequently than healthy controls, whether in monetary choice questionnaires 10,11 or intertemporal choice tasks 12,13 . However, although impaired working memory has frequently been found associated with higher discounting rates 10,11 , cognitive dysfunction alone does not seem to fully account for the abnormal discounting of rewards observed in these patients.…”

Decision value signals in the ventromedial prefrontal cortex and motivational and hedonic symptoms across mood and psychotic disorders

“…In this study, neither diagnosis nor anhedonia was associated with discounting rate. Prior behavioral studies have reported elevated discount rates in SCZ (49,(67)(68)(69)(70), although results are mixed in mood disorders (68,(70)(71)(72)(73)(74)(75). Although not statistically significant in our sample, we observed a trend in individuals with SCZ to discount more than others.…”