Abstract
There is a need for a better understanding of transdiagnostic psychiatric symptoms that relate to neurophysiological abnormalities following rewarding and aversive feedback in order to inform development of novel targeted treatments. To address this need, we examined a transdiagnostic sample of 44 adults (mean age: 35.52; 57% female), which consisted of individuals with broadly-defined schizophrenia-spectrum disorders (n = 16), bipolar disorders (n = 10), other mood and anxiety disorders (n = 5), and no history of a psychiatric disorder (n = 13). Participants completed a Pavlovian monetary reward prediction task during 32-channel electroencephalogram recording. We assessed the event-related potentials (ERPs) of feedback-related negativity (FRN), feedback-related positivity (FRP), and the late positive potential (LPP), following better and worse than expected outcomes. Examination of symptom relationships using stepwise regressions across the entire sample revealed that an increase in the clinician-rated Negative Symptoms factor score from the Positive and Negative Syndrome Scale, was related to a decreased LPP amplitude during better than expected (i.e., rewarding) outcomes. We also found that increased self-reported scores on the Schizotypal Personality Questionnaire (Brief-Revised) Disorganized factor related to an increased FRN amplitude during worse than expected (i.e., aversive) outcomes. Across the entire sample, the FRP component amplitudes did not show significant relationships to any of the symptoms examined. Analyses of the three diagnostic groups of schizophrenia-spectrum disorders, bipolar disorders, and nonpsychiatric controls did not reveal any statistically significant differences across the ERP amplitudes and conditions. These findings suggest relationships between specific neurophysiological abnormalities following rewarding and aversive outcomes and particular transdiagnostic psychiatric symptoms.
Highlights
Abnormalities in reward processing have been reported across a number of psychiatric disorders and may relate to particular transdiagnostic symptoms theoretically related to reward such as anhedonia and avolition [1,2,3,4]
Participants were recruited from the local community in a manner that yielded a wide range of psychiatric disorders, with a directed effort in recruiting individuals with schizophrenia-spectrum and bipolar disorders, as these conditions often include reward processing deficits based on a variety of behavioral, physiological, and neuroimaging methodologies
Our first hypothesis was supported, as individuals with higher Negative Symptom factor scores from the clinician-administered PANSS had a smaller voltage for the late positive potential (LPP) from better than doi:10.1371/journal.pone.0157084.g004
Summary
Abnormalities in reward processing have been reported across a number of psychiatric disorders and may relate to particular transdiagnostic symptoms theoretically related to reward such as anhedonia and avolition [1,2,3,4]. Two studies examined FRN in schizophrenia samples using simple gambling paradigms and both found no difference in a FRN difference waveform amplitude (non-reward minus reward) between individuals with schizophrenia and nonpsychiatric controls [22, 23] It appears that there is only one published study examining FRN in euthymic bipolar disorder which found a reduced FRN amplitude to positive outcomes, suggesting a positive evaluation bias as the reduced FRN is analogous to a larger FRP to reward [24]. Based on the limited literature and theoretical considerations, we hypothesized that the severity of negative symptoms would relate to a reduced sustained processing of emotional stimuli, as indexed by the LPP, but not relate to the immediate conditioning and attentional aspects indexed by the FRP and FRN. Based on initial findings in bipolar disorder and the trait of hypomania, we hypothesized that the pairwise diagnostic comparisons would reveal an enhanced FRP (analogous to attenuated FRN found in previous studies) for the bipolar disorder group when compared to both other groups
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