Neurophysiological responses to unpleasant stimuli (acute electrical stimulations and emotional pictures) are increased in patients with schizophrenia

Cortisol in schizophrenia spectrum disorders: A comprehensive meta-analysis

Schizophrenia spectrum disorders (SSD) are characterized by alterations in cortisol levels across various parameters, including stress reactivity, hair cortisol, and baseline levels, which may be influenced by antipsychotic treatment. To provide a comprehensive overview of cortisol dysregulation in SSD, we conducted meta-analyses assessing (1) the effects of antipsychotic treatment in SSD patients, and additionally comparing cortisol in SSD patients versus healthy controls (HC) (2) following stress induction (metabolic, physiological, psychological stressors), (3) in hair and (4) baseline levels. Systematic literature searches in PubMed, Web of Science, and PsycINFO (November 2024) identified 121 studies (9049 SSD patients) for inclusion. Meta-analytic results revealed that antipsychotic treatment significantly reduced cortisol levels in SSD (k = 16, g = -0.480, 95 % CI [-0.818, -0.142], p = 0.005). Additionally, compared to HC, SSD was associated with reduced cortisol suppression following dexamethasone exposure (k = 9, g = 0.299, 95 % CI [0.091, 0.507], p = 0.005) and with elevated baseline cortisol levels in the morning (k = 71, g = 0.38, 95 % CI [0.210, 0.546], p < 0.001) and evening (k = 11, g = 0.368, 95 % CI [0.076, 0.661], p = 0.014). However, there were no significant group differences in afternoon baseline cortisol, hair cortisol or cortisol reactivity to stress (p > 0.05). These findings offer a detailed understanding of cortisol alterations in SSD and improve our understanding of HPA axis dysregulation in SSD.

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.

Pain sensitivity in patients with schizophrenia: a systematic review and meta-analysis

BACKGROUND

Alterations in pain perception have been observed in people diagnosed with schizophrenia. Some research suggests the existence of a possible hyposensitivity, while others describe a hypersensitivity to pain in people with schizophrenia. In summary, the studies present contradictory results.

Timing matters in elaborative processing of positive stimuli: Gamma band reactivity in schizophrenia compared to depression and healthy adults

Some individuals with schizophrenia report similar feelings of positive affect "in the moment" compared to control participants but report decreased trait positive affect overall. One possible explanation for this disconnection between state and trait positive affect is the extent to which individuals with schizophrenia engage in elaborative processing of positive stimuli. To assess this, we examined evoked gamma band activity in response to positive words over several seconds in a group with schizophrenia, a group with major depressive disorder, and a healthy control group. From a pre-stimulus baseline to 2000 ms after onset of the stimulus (henceforth, "early period"), the schizophrenia group showed a reliable increase in gamma activity compared to both the control and depressed groups, who did not differ from each other. In contrast, the depressed group showed a reliable increase in gamma activity from 2001 to 8000 ms (henceforth, "late period") compared to the other groups, who did not differ from each other. At the same time, the schizophrenia group showed a reliable decrease from the early to late period while the depressed group showed the opposite pattern. In addition, self-reported depression and social anhedonia in the schizophrenia group were related to decreased gamma band activity over the entire processing window. Overall, these results suggest that schizophrenia is associated with increased initial reactivity but decreased sustained elaborative processing over time, which could be related to decreased trait positive affect. The results also highlight the importance of considering depressive symptomology and anhedonia when examining emotional abnormalities in schizophrenia.

Past Pain Experience and Experimentally induced Pain Perception

Many intercurrent factors may be involved in the modulation of the pain message and its expression, such as the previous experience of pain built along the life. In this study, we aimed to determine whether susceptibility to experimentally induced pain is differentially influenced by the individual previous painful experience in subjects with schizophrenia (SC) major depression (MD), and controls (C).

METHODS

The SC (30), MD (32) and C (30) groups participated in experimental pain tests (application of pressure and induction of ischemia) after a semi-structured interview to make an inventory of the previous painful experiences, and the evaluation of anxiety either with autonomic (heart rate, blood pressure) or psychological (Hospital Anxiety Depression scale HAD) measures, and catastrophism.

RESULTS

The reported pain intensities, severities, duration, of the previous pain events, and the number of previous painful events were equivalent in the three groups, except for the number of painful events experimented before the last six months which was lower in the MD group. Experimental pain sensitivity was influenced by the diagnosis, the HAD scores or the number and intensities of previous lived painful events.

CONCLUSION

The lack of a past experience of pain was comparable for the different groups, suggesting that psychiatric disorders do not affect the experience of pain associated with daily life or past events. For each subject, the reported previous experience of pain influences the present feeling of pain.

Is Schizophrenia a Disorder of Consciousness? Experimental and Phenomenological Support for Anomalous Unconscious Processing

Decades ago, several authors have proposed that disorders in automatic processing lead to intrusive symptoms or abnormal contents in the consciousness of people with schizophrenia. However, since then, studies have mainly highlighted difficulties in patients' conscious experiencing and processing but rarely explored how unconscious and conscious mechanisms may interact in producing this experience. We report three lines of research, focusing on the processing of spatial frequencies, unpleasant information, and time-event structure that suggest that impairments occur at both the unconscious and conscious level. We argue that focusing on unconscious, physiological and automatic processing of information in patients, while contrasting that processing with conscious processing, is a first required step before understanding how distortions or other impairments emerge at the conscious level. We then indicate that the phenomenological tradition of psychiatry supports a similar claim and provides a theoretical framework helping to understand the relationship between the impairments and clinical symptoms. We base our argument on the presence of disorders in the minimal self in patients with schizophrenia. The minimal self is tacit and non-verbal and refers to the sense of bodily presence. We argue this sense is shaped by unconscious processes, whose alteration may thus affect the feeling of being a unique individual. This justifies a focus on unconscious mechanisms and a distinction from those associated with consciousness.