Abnormal, affect-specific modulatory effects on early auditory processing in schizophrenia: magnetoencephalographic evidence

Emotional Experience of People With Schizophrenia and People at Risk for Psychosis: A Meta-Analysis

Importance

Psychotic symptoms are associated with subjective reports of aberrant emotion, such as excessive fear or anhedonia, but whether these aberrations reflect aberrant emotional experience of normative stimuli is uncertain both for individuals with schizophrenia and those at risk for psychosis.

Objective

To provide a meta-analysis of study samples of emotional experience in individuals with schizophrenia and those at risk for psychosis as assessed in laboratory-based emotion-induction studies.

Data Sources

MEDLINE and PsycINFO databases were searched for articles published from January 1986 and Google Scholar citations of a relevant earlier meta-analysis until August 2022. Reference lists were manually searched for additional studies.

Study Selection

Included studies measured positive or negative emotional experience in response to standardized emotionally evocative stimuli and compared participants diagnosed with schizophrenia or participants at risk for psychosis with healthy controls.

Data Extraction and Synthesis

The meta-analysis was registered with PROSPERO and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. Data were extracted by 2 independent coders, and random-effects analyses were conducted.

Main Outcomes and Measures

Outcomes were 3 scales of emotional experience (unipolar positive emotion, unipolar negative emotion, bipolar valence), analyzed separately for pleasant, neutral, and unpleasant stimuli. A meta-analysis was conducted for differences between the 2 clinical groups combined and controls. Subgroup differences (schizophrenia vs at risk) and the influence of several other variables were tested in moderator analyses.

Results

This systematic review and meta-analysis included data from 111 studies and 6913 participants (schizophrenia: 2848 [41.2%]; at risk: 877 [12.7%]; healthy controls: 3188 [46.1%]). Compared with controls, people with schizophrenia and those at risk for psychosis experienced pleasant stimuli as less positive (unipolar positive: standardized mean difference [SMD] Hedges g = -0.19; P =.001; bipolar valence: SMD Hedges g = -0.28; P <.001) and more negative (Hedges g = 0.52; P <.001), neutral stimuli as more negative (Hedges g = 0.55; P <.001), and unpleasant stimuli as both more positive (unipolar positive: SMD Hedges g = 0.23; P =.005; bipolar valence: Hedges g = 0.12; P =.01) and more negative (Hedges g = 0.22; P <.001). Moderator analyses indicated a less aberrant emotional experience for odors than for visual stimuli (unipolar negative, pleasant z score = -2.97; P =.003; unipolar negative, neutral z score = -2.70; P =.007), an association between higher negative symptoms and diminished positive emotion for pleasant stimuli in schizophrenia (z score = -2.98; P =.003), and that subgroup differences were limited to neutral stimuli.

Conclusions and Relevance

Results suggest a pattern of aberrant emotional experience of normative stimuli in schizophrenia and that this already was observable before disorder onset. In particular, the aberrant experience of pleasant stimuli needs to be considered as an intervention target.

Tinnitus-on the interplay between emotion and cognition

Subjective tinnitus (hereafter tinnitus) is often considered and studied as a perceptual phenomenon. Accordingly, various abnormalities in the area of cognitive processing have been reported in patients with tinnitus. At the same time, the disorder is characterized by considerable emotional distress, which is associated with a high comorbidity of affective disorders. Here, we aim to outline the close link between cognition and emotion, and how current research from the field of cognitive neuroscience examines the processing and acquisition of emotional stimuli. The emotional valence of stimuli can be acquired after brief exposure to learning, leading from neutral to appetitive or aversive evaluation. In contrast to neutral stimuli, emotional stimuli attract attention very early (about 100 ms) during processing, leading to deeper processing and corresponding memory effects. The involved subcortical and cortical network encompasses limbic and sensory areas. In particular, prefrontal regions are involved in the acquisition and evaluation of emotional stimuli as also shown in studies of patients with affect disorders. The interplay of cognitive and emotional processes seems to be central to the development, maintenance, and treatment of tinnitus.

[Tinnitus-on the interplay between emotion and cognition. German version]

Subjective tinnitus (hereafter tinnitus) is often considered and studied as a perceptual phenomenon. Accordingly, various abnormalities in the area of cognitive processing have been reported in patients with tinnitus. At the same time, the disorder is characterized by considerable emotional distress, which is associated with a high comorbidity of affective disorders. Here, we aim to outline the close link between cognition and emotion, and how current research from the field of cognitive neuroscience examines the processing and acquisition of emotional stimuli. The emotional valence of stimuli can be acquired after brief exposure to learning, leading from neutral to appetitive or aversive evaluation. In contrast to neutral stimuli, emotional stimuli attract attention very early (about 100 ms) during processing, leading to deeper processing and corresponding memory effects. The involved subcortical and cortical network encompasses limbic and sensory areas. In particular, prefrontal regions are involved in the acquisition and evaluation of emotional stimuli as also shown in studies of patients with affect disorders. The interplay of cognitive and emotional processes seems to be central to the development, maintenance, and treatment of tinnitus.

Common and separable behavioral and neural mechanisms underlie the generalization of fear and disgust

Generalization represents the transfer of a conditioned responses to stimuli that resemble the conditioned stimulus (CS). Previous studies on generalization of defensive avoidance responses have primarily focused on fear and have neglected disgust generalization, which represents a key pathological mechanism in some anxiety disorders. In the present study we examined common and distinct mechanisms of fear and disgust generalization by means of a fear or disgust multi-CS conditioning and generalization paradigm with concomitant event-related potential (ERPs) acquisition in n = 62 subjects. We demonstrate that compared to fear, disgust-relevant generalized stimuli (GS) elicited larger expectancy ratings and longer reaction times (RTs) reflecting stronger ratings of 'risk'. On the electrophysiological level, increased P2 amplitudes were found in response to conditioned CS+ versus CS- across both domains, possibly reflecting higher motivational and attentional salience of aversive conditioned stimuli per se. Contingent negative variation (CNV) amplitude was significantly larger for disgust-CS+ than disgust-CS-, reflecting a stronger preparation of the disgust US. Additionally, we found that the contingent negative variation (CNV) fear generalization gradient, and CNV amplitude were increased with similarity to CS+. In contrast the CNV to disgust-GS did not differ and did not reflect disgust generalization. Together this may indicate that the CNV represents a highly fear-specific index for generalization learning. This study provides the first neurobiological evidence for common and distinct generalization learning in fear versus disgust suggesting that dysregulations in separable defensive avoidance mechanisms may underly different anxiety disorder subtypes.

An evil face? Verbal evaluative multi-CS conditioning enhances face-evoked mid-latency magnetoencephalographic responses

Humans have a remarkable capacity for rapid affective learning. For instance, using first-order US such as odors or electric shocks, magnetoencephalography (MEG) studies of multi-CS conditioning demonstrate enhanced early (<150 ms) and mid-latency (150–300 ms) visual evoked responses to affectively conditioned faces, together with changes in stimulus evaluation. However, particularly in social contexts, human affective learning is often mediated by language, a class of complex higher-order US. To elucidate mechanisms of this type of learning, we investigate how face processing changes following verbal evaluative multi-CS conditioning. Sixty neutral expression male faces were paired with phrases about aversive crimes (30) or neutral occupations (30). Post conditioning, aversively associated faces evoked stronger magnetic fields in a mid-latency interval between 220 and 320 ms, localized primarily in left visual cortex. Aversively paired faces were also rated as more arousing and more unpleasant, evaluative changes occurring both with and without contingency awareness. However, no early MEG effects were found, implying that verbal evaluative conditioning may require conceptual processing and does not engage rapid, possibly sub-cortical, pathways. Results demonstrate the efficacy of verbal evaluative multi-CS conditioning and indicate both common and distinct neural mechanisms of first- and higher-order multi-CS conditioning, thereby informing theories of associative learning.