Digital phenotyping evidence for the reduced positivity offset as a mechanism underlying anhedonia among individuals at clinical high-risk for psychosis.

Prior studies suggest that the "anhedonia paradox" in schizophrenia (i.e., discrepant results indicating intact hedonic reactivity despite reduced frequency of pleasure-seeking activity) can be explained by a reduction in the "positivity offset" (i.e., a reduction in the normative tendency to experience greater positive than negative affect during low arousal neutral contexts that promote reward-seeking behavior). In the current study, we examined whether the positivity offset is relevant to explaining anhedonia and liability for psychosis among individuals at clinical high-risk for psychosis (CHR) (i.e., individuals exhibiting attenuated hallucinations or delusions that cause distress and functional decline). Mathematical modeling approaches from Cacioppo's Evaluative Space Model were applied to six days of digital phenotyping data collected in daily life among 100 individuals at CHR and 57 healthy controls (CN). Participants reported levels of positive emotion, negative emotion, and arousal throughout the day via ecological momentary assessment (EMA) surveys while accelerometry was passively recorded. EMA surveys were used to calculate the positivity offset and examine associations with real-world motivated behavior. Results indicated that the positivity offset was present among individuals at CHR, but diminished compared to CN. Importantly, smaller positivity offset scores were associated with greater clinically rated anhedonia, particularly among CHR cases with comorbid mood disorder diagnoses. Findings suggest that reductions in the positivity offset are a mechanism underlying anhedonia across phases of psychotic illness and represent a novel treatment target that is relevant for the treatment of negative symptoms and prevention of psychotic disorders.