Anhedonia is common in schizophrenia patients, but treatments have not been especially successful, possibly because of a lack of understanding the mechanisms behind anhedonia in these patients, Sydney H. James, a PhD candidate at the University of Georgia, Athens, and colleagues wrote.
Although many schizophrenia (SZ) patients exhibit anhedonia on diagnosis in a clinical interview setting, other recent research shows comparable response to pleasant stimuli between schizophrenic patients and healthy controls. The researchers proposed that anhedonia “reflects abnormalities in the valuation of desired affective states in individuals with SZ,” with differences between actual and ideal affect.
In a study published in the Journal of Psychiatric Research, the researchers identified 32 outpatients with schizophrenia and 29 healthy controls. The SZ participants were recruited from community outpatient mental health services in Georgia. All participants completed Structured Clinical Interview for DSM-5 Disorders and the SCID-5 Personality Disorders. Participants then completed the Affect Valuation Index and measures of negative symptom severity. Negative symptom severity was measured using the Negative Symptom Inventory-Self-Report, an 11-item questionnaire assessing three specific experiential and behavioral components (anhedonia, avolition, and asociality) over the past week.
The average age of the SZ patients and controls was approximately 40 years, and 10 SZ patients and 5 controls were male.
Overall, the researchers found a significant main effect of group, a significant main effect of arousal, and a significant group X arousal interaction for positive affect discrepancy scores. For negative affect discrepancy scores, they found a significant main effect on group, nonsignificant main effect of arousal, and significant group X arousal interaction.
Individuals with SZ showed greater positive and negative emotion discrepancy scores, compared with controls, in contrast to the researchers’ hypothesis. “Those diagnosed with SZ were more likely to want to feel less negative than they actually did,” they wrote. The negative affect discrepancy scores were positively associated with negative symptoms. The discrepancies between actual and ideal affect may be impacted by social interactions and the perceived expectations of others for levels of negative affect.
The study findings were limited by the small sample size and inability to test the relationship between ideal and actual affect as related to low-pleasure beliefs, which merits further study, the researchers noted. Other limitations include the focus on an outpatient population with mild to moderate SZ, and the use of a trait format to measure affect rather than experiential emotion knowledge.
However, the results have practical implications for treatment and suggest that, “given the positive associations between negative symptom and affect discrepancy scores, psychosocial treatments could target expectations for future positive and negative emotional experience,” and ecological momentary assessment could be used to track affect through a period of treatment and prompt conversations between SZ patients and therapists about discrepancies, they concluded.
The study participants were compensated by the National Institute of Mental Health through a grant to a corresponding author. Ms. James had no financial conflicts to disclose.