Social cognition and functional outcome in schizophrenia: The moderating role of cardiac vagal tone

The Heart in the Mind: A Systematic Review and Meta-Analysis of the Association Between Theory of Mind and Cardiac Vagal Tone

Theory of mind (ToM) is the human ability to infer the mental states of others in order to understand their behaviors and plan own actions. In the past decades, accumulating evidence has shown that heart rate variability (HRV), an index of parasympathetic control of the heart, is linked to behavioral regulation, social competence, and social cognition abilities, all implicated-to some extent-in ToM. This study aims to systematically review and meta-analyze the available studies, investigating the relation between ToM and HRV in typically developing people. Six studies were eligible for the meta-analysis, yielding a significant association between HRV and ToM of a small-to-medium effect size (g = 0.44). This result was not influenced by publication bias. Due to the small number of studies eligible for the meta-analysis, it was not possible to test for the effect of categorical moderators. The moderating role of sex and quality of the studies was examined by meta-regression analysis. Moderation analysis did not yield any significant effect; however, at a descriptive level, studies yielding the largest effect size were characterized by the use of high frequency-HRV assessment at rest and the Reading the Mind in the Eyes Test to evaluate ToM abilities. The results preliminarily suggest that tonic HRV might be used as an indicator of the ability to understand the content of mind of others.

Enhancement of aerobic fitness improves social functioning in individuals with schizophrenia

Individuals with schizophrenia display substantial deficits in social functioning (SF), characterized by chronic, lifelong presentations. Yet, at present there are few effective interventions to enhance SF in this population. Emerging evidence from studies of clinical populations that display similar SF deficits suggests that aerobic exercise (AE) may improve social skills. However, this putative impact has not been investigated in schizophrenia. Employing a single-blind, randomized clinical trial design, 33 individuals with schizophrenia were randomized to receive 12 weeks of Treatment-As-Usual (TAU; n = 17) or TAU + AE (n = 16) utilizing active-play video games (Xbox 360 Kinect) and traditional AE equipment. Participants completed an evaluation of aerobic fitness (VO₂max) as well as self-, informant-, and clinician-reported SF measures at baseline and after 12 weeks. Twenty-six participants completed the study (79%; TAU = 13; AE = 13). At follow-up, the AE participants improved their VO₂max by 18.0% versus - 0.5% in the controls (group x time interaction, F_1,24 = 12.88; p = .002). Hierarchical stepwise regression analyses indicated improvements in VO₂max significantly predicted enhancement in SF as indexed by self-, informant-, and clinician-reported measures, predicting 47%, 33%, and 25% of the variance, respectively (controlling for baseline demographics, medications, mood symptoms, and social networks). Compared to the TAU group, AE participants reported significant improvement in SF (23.0% vs. - 4.2%; group × time interaction, F_1,24 = 7.48, p = .012). The results indicate that VO₂max enhancement leads to improvements in SF in people with schizophrenia. Furthermore, low VO₂max represents a modifiable risk factor of SF in people with schizophrenia, for which AE training offers a safe, non-stigmatizing, and nearly side-effect-free intervention.

Associations between physiological responses to social-evaluative stress and daily functioning in first-episode schizophrenia

Schizophrenia (SZ) is associated with impaired adaptive functioning, including difficulties managing the demands of independent living, work, school, and interpersonal relationships. Prior studies have linked the physiological stress response with less effective coping in daily life. Differences in stress-response tendencies may also support heterogeneity in daily functioning in SZ. The present study examined two established measures of the stress response in patients with first-episode SZ. Salivary cortisol was included as an index of hypothalamic-pituitary-adrenal response. Vagal suppression (VS), a measure of stress-related reduction in heart rate variability, was used to assess parasympathetic flexibility. Greater cortisol response and VS to social-evaluative stress were predicted to be associated with better functioning in SZ over and above relationships with social cognition and neurocognition, two well-established predictors of functional outcome. Thirty-eight first-episode SZ outpatients and 29 healthy comparison subjects (HC) provided social cognitive, neurocognitive, and physiological measurements before and after the Trier Social Stress Test (TSST). Although SZ and HC did not differ on VS to the TSST, patients exhibited significant associations between VS and functioning across all four domains of the Role Functioning Scale. Furthermore, greater VS predicted more effective functioning with friends, beyond the contributions associated with social cognition and neurocognition, and strengthened the positive effects of higher levels of social cognition on independent living/self-care. VS elicited by social-evaluative stress in the laboratory may reflect stress-response tendencies in daily life that are relevant for daily functioning in first-episode SZ.

Improved facial affect recognition in patients with first-episode psychosis

AIM

The present study aimed at assessing whether impaired facial affect recognition (FAR) in patients with first-episode psychosis (FEP) would improve after a brief intervention targeting FAR specifically.

METHODS

Thirty-five outpatients and 38 healthy controls were administered an intervention which involved training to recognize emotional information, conveyed by changes in facial features. Using a pre- and post-intervention design, two measurements of FAR were conducted using an experimental procedure with alternative sets of stimuli.

RESULTS

We found improved overall FAR performance in both participant groups with marked effects in recognizing anger, disgust and fear. Patients' post-intervention performance was comparable to healthy participants' baseline performance.

CONCLUSIONS

The present improvement in facial affects recognition in FEP patients, despite only somewhat impaired, emphasizes the importance of early targeted interventions for FAR in psychosis. Further research is needed to assess whether this improvement will generalize to global social functioning.

Early Signs of Schizophrenia and Autonomic Nervous System Dysregulation: A Literature Review

OBJECTIVE

Recent research suggests that early signs of schizophrenia can be detected several years before its onset. Evidence suggests that the identification of at-risk individuals before the psychotic onset can significantly improve the course of the disorder. However, instruments employed for the detection of prodromal symptoms are far from being accurate in the prediction of a future transition to psychosis. The aim of the present review is to summarize literature on the early signs of schizophrenia and to identify physiological markers that may aid the identification of the disorder before psychotic transition.

METHOD

This critical review includes studies published between 1979 and 2018 that were indexed in major databases with the following keywords: schizophrenia, prodromal phase, basic symptoms, autonomic nervous system, heart rate variability.

RESULTS

The examination of the relevant literature showed that, despite recent progress in the identification of at-risk states, the currently employed instruments do not allow an effective prediction of a future psychotic onset. Also, evidence suggests a significant association between alterations in the autonomic nervous system (ANS) functioning and psychotic disorders. However, literature on the association between ANS functioning and at-risk states for psychosis is still scarce. The addition of physiological risk indicators may represent a step forward in the detection of at-risk individuals.

CONCLUSIONS

Overall, the present literature review highlights that a future schizophrenic onset cannot be strongly predicted with current available measures. Given the established correlation between schizophrenia and autonomic dysregulation, an investigation of the ANS functioning in individuals who are at increased risk of developing schizophrenia may be particularly useful to improve the quality of the assessment, to identify at an early stage the dysregulated physiological patterns that have been linked with schizophrenia, and therefore to develop tailored interventions. Accordingly, it is crucial that future research investigates the presence of autonomic deficits in individuals at risk for psychosis.

Aberrant parasympathetic reactivity to acute psychosocial stress in male patients with schizophrenia spectrum disorders

Autonomic dysfunction represents a core domain of the pathophysiology of schizophrenia spectrum disorders (SCZ), with aberrant physiologic arousal underlying maladaptive social and cognitive behaviors. Antagonistic parasympathetic and sympathetic systems support autonomic flexibility to appropriately regulate arousal and respond to environmental challenges, which can be modeled using physiologic measures. SCZ patients consistently show heightened basal stress, however, their parasympathetic reactivity to an acute psychosocial stressor is poorly understood. Heart period (HP-arousal), respiratory sinus arrhythmia (RSA-parasympathetic vagal activity), and their relationship were measured in SCZ patients (n = 19) and healthy controls (n = 20) at baseline and during psychosocial stress exposure. Parasympathetic vagal control of arousal, reflected in RSA-HP coupling, was assessed for the first time in SCZ. Patients demonstrated blunted physiologic reactivity (less change in heart period and respiratory sinus arrhythmia), a unique increase in respiratory sinus arrhythmia relative to baseline during recovery, and elevated arousal was associated with poor cognitive performance and greater positive symptoms. Arousal regulation was tightly controlled by parasympathetic activity in controls only, indicated by a strong association between changes in heart period and respiratory sinus arrhythmia. Results are the first to demonstrate maladaptive, inefficient parasympathetic arousal regulation (RSA-HP decoupling) in reaction to psychosocial stress in SCZ, representing an autonomic profile incompatible with appropriate social and emotional functioning.

Autonomic nervous system dysfunction in psychiatric disorders and the impact of psychotropic medications: a systematic review and meta-analysis

BACKGROUND

Autonomic nervous system (ANS) dysfunction is a putative underlying mechanism for increased cardiovascular disease risk in individuals with psychiatric disorders. Previous studies suggest that this risk may be related to psychotropic medication use. In the present study we systematically reviewed and analyzed published studies of heart rate variability (HRV), measuring ANS output, to determine the effect of psychiatric illness and medication use.

METHODS

We searched for studies comparing HRV in physically healthy adults with a diagnosed psychiatric disorder to controls and comparing HRV pre- and post-treatment with a psychotropic medication.

RESULTS

In total, 140 case-control (mood, anxiety, psychosis, dependent disorders, k = 151) and 30 treatment (antidepressants, antipsychotics; k = 43) studies were included. We found that HRV was reduced in all patient groups compared to controls (Hedges g = -0.583) with a large effect for psychotic disorders (Hedges g = -0.948). Effect sizes remained highly significant for medication-free patients compared to controls across all disorders. Smaller and significant reductions in HRV were observed for specific antidepressants and antipsychotics.

LIMITATIONS

Study quality significantly moderated effect sizes in case-control analyses, underscoring the importance of assessing methodological quality when interpreting HRV findings.

CONCLUSION

Combined findings confirm substantial reductions in HRV across psychiatric disorders, and these effects remained significant even in medication-free individuals. Reductions in HRV may therefore represent a significant mechanism contributing to elevated cardiovascular risk in individuals with psychiatric disorders. The negative impact of specific medications on HRV suggest increased risk for cardiovascular disease in these groups, highlighting a need for treatment providers to consider modifiable cardiovascular risk factors to attenuate this risk.