Emotion processing and schizophrenia

Sometimes, I read research that seems contradictory. This may be one of those cases. Osborne et al. (2023) published “Clinical High Risk for Psychosis Syndrome is Associated with Reduced Neural Responding to Unpleasant Images” in Journal of Psychopathology and Clinical Science. Here are the edited abstract and impact statements:

Deficits in emotion processing are core features of psychotic disorders. Electrophysiology research in schizophrenia suggests deficits in sustained engagement with emotional content (indexed by the late positive potential [LPP]) may contribute to emotion processing impairments. Despite similar behavioral emotion processing dysfunction in those at clinical high risk (CHR) for psychosis, limited research has examined neural mechanisms of impaired emotion processing in the high-risk period, where research can inform risk models. To examine mechanisms of emotion processing deficits in those at CHR for psychosis, the present study used a passive viewing task to elicit the LPP in response to emotionally engaging and neutral stimuli in 28 CHR and 32 control participants (60% female). Relative to controls, CHR participants showed reduced LPP amplitude when viewing unpleasant images (d = 0.75, p = .005) but similar LPP amplitude in response to both neutral (d = 0.35, p = .19) and pleasant images (d = 0.31, p = .24). This pattern suggests that individuals at CHR for psychosis exhibit a deficit in sustained engagement with unpleasant stimuli. Clinical and trait questionnaires were administered to examine potential exploratory explanations for group differences in LPP amplitude. Consistent with evidence suggesting LPP amplitude reflects engagement of approach/avoidance motivational systems, greater LPP amplitude was associated with greater trait-level behavioral avoidance in control participants (r = .42, p = .032) but not CHR participants (r = –.21, p = .40). Together, the present research is consistent with LPP studies in psychosis and implicates reduced sustained engagement with emotional content in the high-risk period.

Deficits in emotion processing are prevalent in individuals at risk for developing psychosis. This study supports the notion that for individuals at risk for psychosis, impairments in orienting and sustaining engagement with emotional content may underlie emotion processing deficits and be due to abnormalities in approach–avoidance motivational systems. Together, these findings suggest that deficits in orienting and sustaining engagement to emotional content may be present before illness onset and reflect a core feature of the illness. 

The late positive potential is measured using EEG and is seen as related to emotion processing. So, in this study, the focus seems to be on a motivational deficit in processing unpleasant stimuli. Next, Whearty, Ruiz, Knippenberg & Strauss (2024) published “Anhedonia Reflects an Encoding Deficit for Pleasant Stimuli in Schizophrenia: Evidence from the emotion-induced memory trade-off eye-tracking paradigm” in Neuropsychology.  Edited abstract and impact statements:

The present study explored the hypothesis that anhedonia reflects an emotional memory impairment for pleasant stimuli, rather than diminished hedonic capacity in individuals with schizophrenia (SZ). Participants included 30 SZ and 30 healthy controls (HCs) subjects who completed an eye-tracking emotion-induced memory trade-off task where contextually relevant pleasant, unpleasant, or neutral items were inserted into the foreground of neutral background scenes. Passive viewing and poststimulus elaboration blocks were administered to assess differential encoding mechanisms, and immediate and 1-week recognition testing phases were completed to assess the effects of delay interval. Participants also made self-reports of positive emotion, negative emotion, and arousal in response to the stimuli. Results indicated that SZ experienced stimuli similarly to HC. Both groups demonstrated the typical emotion-induced memory trade-off during the passive viewing and poststimulus elaboration encoding blocks, as indicated by more hits for emotional than neutral items and fewer hits for backgrounds paired with emotional than neutral items. Eye-tracking data also indicated that both groups were more likely to fixate earlier and have longer dwell time on emotional than neutral items. At the 1-week delay, the emotion-induced memory trade-off was eliminated in both groups, and SZ showed fewer overall hits across valence conditions. Greater severity of anhedonia was specifically associated with impaired recognition for pleasant stimuli at the immediate recognition phase. Findings suggest that anhedonia in SZ is associated with emotional memory impairment, particularly a deficit in encoding positive stimuli. 

Is anhedonia associated with an emotional memory impairment in schizophrenia? Anhedonia was selectively associated with a deficit in encoding pleasant stimuli; however, it was not associated with impairments in attention or long-term memory for pleasant stimuli. Clinically rated anhedonia, which relies on retrospective reports of pleasure, is associated with impaired encoding for positive information in schizophrenia (i.e., a cognitive deficit). Additional research examining the role of emotional memory in anhedonia in schizophrenia is needed using neuroimaging to identify neural substrates of the encoding deficit reported here; cognitive training interventions focused on encoding may be beneficial for improving clinical outcome if findings are consistently replicated. 

This study used eye-tracking data and examined people with schizophrenia rather than people at clinically high risk for psychosis. Here, the deficit seems to be in encoding positive stimuli, a cognitive deficit. In the end, the two findings may not be in conflict with one another. In any case, examining responses to emotional stimuli may be helpful in individuals at risk for psychosis.