Stress axis dysfunction in schizophrenia

Examining the psychobiological response to acute social stress across clinical stages and symptom trajectories in the early psychosis continuum

The stress-vulnerability model has been repeatedly highlighted in relation to the risk, onset and course of psychosis, and has been independently studied in clinical high-risk (CHR) and first-episode psychosis (FEP) populations. Notable in this literature, however, is that there are few studies directly comparing markers of stress response across progressive stages of illness. Here we examined the psychobiological response to the Trier Social Stress Test in 28 CHR (mean age 19.1) and 61 FEP (age 23.0) patients, in order to understand the stage(s) or trajectories in which differences in subjective stress or physiological response occur. The overall clinical sample had greater perceived stress and blunted cortisol (FEP + CHR, n = 89, age 21.7) compared with healthy controls (n = 45, age 22.9). Additional analyses demonstrated elevated heart rate and systolic blood pressure in FEP compared with CHR, but there were no further differences in physiological parameters (cortisol, heart rate, or blood pressure) between stage- or trajectory-based groups. Together, this suggests that individual stress response markers may differentially emerge at particular stages en route to psychosis - and demonstrates how stage-based analyses can shed light on the emergence and evolution of neurobiological changes in mental illness.

Effects of mind-body therapies on schizophrenia: A systematic review and network meta-analysis

OBJECTIVE

The objective of this meta-analysis is to evaluate and compare the effectiveness of different mind-body therapies in reducing the symptoms of schizophrenia.

METHODS

A systematic search was performed using databases such as PubMed, Embase, Cochrane Library, Web of Science, and Scopus. Randomized controlled trials that assessed the effects of mind-body therapies on patients with schizophrenia were included. The search covered the period between the inception of each database and November 17th, 2022. The methodological quality of the trials was assessed using the Cochrane risk of bias tool. A network meta-analysis was conducted to compare the effects of various mind-body therapies, including Yoga, Mindfulness, Tai Chi, Baduanjin, and Yijinjing.

RESULTS

The analysis included 22 randomized controlled trials involving a total of 2064 subjects. The network meta-analysis revealed that Yoga and Mindfulness interventions were more effective than other mind-body therapies in reducing the symptoms of schizophrenia. Specifically, Yoga improved PANSS-positive symptom scores (SUCRA: 74.8 %) and PANSS-negative symptom scores (SUCRA: 80.4 %), whereas Mindfulness improved PANSS-positive symptom scores (SUCRA: 85.6 %).

CONCLUSION

The findings of this study indicate that Yoga may be a promising intervention for the treatment of schizophrenia. However, the small sample size and the low quality of the included studies have limited the generalizability of our findings Therefore, this study must be understood with caution, and further investigation is warranted when more relevant studies emerge.

Efficacy of Yoga therapy for the management of psychopathology of patients having chronic schizophrenia

BACKGROUND

There is a large body of literature and scientific data regarding the efficacy of pharmacological and psychosocial interventions for schizophrenia, however, studies on Yoga therapy is scanty. Yoga is a means of balancing and harmonizing the body, mind and emotion, and for enlightening the mind and upliftment of the total personality.

AIMS

The present study was conducted to determine the efficacy of Yoga therapy as an adjunctive therapy and to see its effects on psychopathology on the patients suffering from chronic schizophrenia.

SETTINGS AND DESIGN

Pre- and post-test design with the control group.

MATERIALS AND METHODS

It is a study using purposive sampling technique by which 30 chronic schizophrenic patients were selected and 15 patients were randomly assigned to Yoga therapy along with pharmacotherapy (experimental group), and 15 were assigned pharmacotherapy alone (control group) after the baseline assessment using Positive and Negative Syndrome Scale (PANSS). The Yoga group attended Yoga therapy everyday for about 1½ h including motivational and feedback session.

RESULTS

At the end of 1 month postassessment was done, and schizophrenic patients, who received the yogic intervention showed better rating than those in pharmacotherapy alone on PANSS variables.

CONCLUSION

Yoga could be a right choice for improving psychopathology resulting in better quality of life along with other pharmacological management and psychosocial interventions.

Much ado about much: stress, dynamic biomarkers and HPA axis dysregulation along the trajectory to psychosis

OBJECTIVES

In the context of a stress-vulnerability framework, hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis is thought contribute to the risk, onset and course of psychotic illness. However, recent reports regarding static and dynamic features of the HPA axis suggest a more complex set of phenomena at play in the early phases of psychosis.

METHODS

We review literature regarding structural and functional aspects of the HPA axis in subjects at risk for or experiencing the first episode of psychosis, including evidence favoring as well as that which contradicts a model of HPA axis hyperactivation.

RESULTS

Static measures of diurnal cortisol and hippocampal/pituitary volumes suggest that the HPA axis is in a hyperactivated state in early phases of psychosis. In contrast, the dynamic cortisol response to encountered or anticipated stress is blunted in the same populations. These incongruent findings need to be better understood.

CONCLUSIONS

We consider potential explanations for the seemingly contradictory elevation and blunting of HPA biomarkers in the early course of psychosis. Finally, we propose and explore implications of a conceptual model of tonic HPA hyperactivation and phasic HPA blunting that integrates and reconciles these data.

The effects of phencyclidine (PCP) on anxiety-like behavior in the elevated plus maze and the light-dark exploration test are age dependent, sexually dimorphic, and task dependent

Previous research in our laboratory revealed sexually dimorphic effects of prior exposure to phencyclidine (PCP) on elevated plus maze behavior. In an attempt to examine the developmental time course of this effect and determine the extent to which it generalizes to other anxiety paradigms, young adult (61-64 days old) and adult (96-107 days old) male and female rats were treated with PCP (15 mg/kg) or saline. Following a two week withdrawal period, animals were tested in either the elevated plus maze (EPM) or a light-dark exploration (LD) test. In adults, both tests revealed a sexually dimorphic effect driven by PCP-induced decreases in anxiety in females as indicated by increased time spent in the open arms of the EPM and in the lit compartment of the LD test and increased anxiety in males as indicated by decreased time spent in the lit compartment of the LD. In young animals, PCP pretreatment decreased open arm exploration in the elevated plus maze, indicating increased anxiety. However, PCP increased time spent in the light compartment in the light-dark exploration test, indicating decreased anxiety. Corticosterone levels measured 15 min after the onset of the EPM failed to reveal an association between the behavioral effects of PCP and corticosterone levels. The results in adults substantiate the previously observed sexually dimorphic effect of PCP on elevated plus maze behavior in adults and indicate that the effect generalizes to another anxiety paradigm. The results in the younger animals suggest an age dependent effect of PCP on anxiety in general and indicate that behaviors in the elevated plus maze and the light-dark exploration test reflect dissociable psychobiological states.

Abnormal brain response during the auditory emotional processing in schizophrenic patients with chronic auditory hallucinations

OBJECTIVE

Few neuroimaging studies have been conducted regarding clinical associations between auditory hallucinations (AHs) and affective disturbances in patients with schizophrenia. This study aimed to elucidate the neurobiological basis of emotional disturbances in schizophrenic patients with persisting AHs.

METHODS

Using functional magnetic resonance imaging (fMRI), the cortical responsiveness during the processing of laughing and crying sounds was measured and compared between 14 hallucinating schizophrenic patients, 14 nonhallucinating schizophrenic patients and 28 normal controls.

RESULTS

The hallucinating patients showed differential neural activities in various areas including the amygdala, the hippocampus, the cingulate, the prefrontal cortex, and the parietal cortex, compared with the nonhallucinating patients and the normal controls. In particular, compared with the nonhallucinators, the hallucinators revealed reduced activation in the left amygdala and the bilateral hippocampus during the processing of crying sounds.

CONCLUSION

Our findings suggest that the persistence of AHs in schizophrenia may induce functional disturbances of the emotion-related interconnected neural networks, including reduced responsiveness in the amygdala and hippocampus to negative stimuli.

Beacon-like/ubiquitin-5-like immunoreactivity is highly expressed in human hypothalamus and increased in haloperidol-treated schizophrenics and a rat model of schizophrenia

The beacon gene is involved in the regulation of energy metabolism, food intake, and obesity. We localized its gene product, beacon-/ubiquitin 5-like immunoreactivity in brains of normal-weight, non-psychotic individuals, adipose (BMI over 32), non-psychotic individuals, and haloperidol-treated schizophrenics. The protein was found to be highly expressed in many neurons of the paraventricular and supraoptic hypothalamic nuclei. Besides, it was detected in neurons of other hypothalamic areas (suprachiasmatic, arcuate, and ventromedial nuclei) as well as outside the hypothalamus (Nuc. basalis Meynert, thalamus, hippocampus, and some neocortical areas). A morphometric analysis of beacon-immunoreactive hypothalamic and neocortical neurons revealed that compared to normal-weight controls in haloperidol-treated schizophrenics, there was a significant increase of protein-expressing supraoptic, paraventricular, and orbitofrontal neurons. However, a significant increase in beacon-expressing supraoptic neurons was also seen in adipose, non-psychotic individuals in comparison with normal-weight controls. Haloperidol at different doses has no effect on beacon expression in SHSY5Y neuroblastoma cells, which makes the assumption unlikely that haloperidol per se is responsible for the increased neuronal expression of the peptide in schizophrenics. In rats with a neonatal lesion of the ventral hippocampus (a widely used animal model of schizophrenia), we found an increased neuronal expression of beacon in the paraventricular and supraoptic nuclei. We suppose that elevated hypothalamic expression of beacon-like protein in non-obese schizophrenics is not primarily related to metabolic alterations, but to a certain role in schizophrenia, which is possibly unrelated to aspects of weight gain and obesity. The latter assumption finds some support by data obtained in rats with ventral hippocampus lesion.

A new look at the neural diathesis--stress model of schizophrenia: the primacy of social-evaluative and uncontrollable situations

The neural diathesis-stress model of schizophrenia proposes that stress, through its effects on cortisol production, acts upon a preexisting vulnerability to trigger and/or worsen the symptoms of schizophrenia. In line with its focus on the neurobiology of stress response in schizophrenia, this model treats stressors as a homogeneous category. Recent research has shown that, in healthy individuals, cortisol is most strongly produced in response to stressors that result from perceived uncontrollable threats to important goals and/or social-evaluative threats. We hypothesize that it is specifically these stressors that trigger and/or worsen the symptoms of schizophrenia in those with a preexisting vulnerability. This hypothesis may provide a way of making sense of contradictory findings on the relations between stress and schizophrenia. We propose some empirical tests of this hypothesis and explore implications for the treatment and management of the disorder.

Yoga therapy as an add-on treatment in the management of patients with schizophrenia--a randomized controlled trial

OBJECTIVE

Treatment of schizophrenia has remained unsatisfactory despite the availability of antipsychotics. This study examined the efficacy of yoga therapy (YT) as an add-on treatment to the ongoing antipsychotic treatment.

METHOD

Sixty-one moderately ill schizophrenia patients were randomly assigned to YT (n = 31) and physical exercise therapy (PT; n = 30) for 4 months. They were assessed at baseline and 4 months after the start of intervention, by a rater who was blind to their group status.

RESULTS

Forty-one subjects (YT = 21; PT = 20) were available at the end of 4 months for assessment. Subjects in the YT group had significantly less psychopathology than those in the PT group at the end of 4 months. They also had significantly greater social and occupational functioning and quality of life.

CONCLUSION

Both non-pharmacological interventions contribute to reduction in symptoms, with YT having better efficacy.

Neurotrophins and schizophrenia

Neurotrophins have established roles in neuronal development, synaptogenesis, and response to stress/anxious stimuli. Moreover, these agents are neuromodulators of monoaminergic, GABAergic, and cholinergic systems. Amidst a growing appreciation of the developmental neurobiology of schizophrenia--as well as the propensity for progressive brain changes--there is emergent information on abnormalities in the expression of neurotrophins in schizophrenia. This article reviews the literature on neurotrophins and schizophrenia. A schema for understanding the neurobiology of relapse in schizophrenia is offered.

Delayed suppression of hippocampal cell proliferation in rats following inescapable shocks

Adult Sprague-Dawley rats were exposed to a single session of 100 inescapable tail shocks (IS). Bromodeoxyuridine (BrdU) was administered 1 h, 2 days or 7 days later and hippocampal cell proliferation (CP) was assessed after a 2-h survival period. Measures of plasma corticosterone (CORT) levels were also obtained. Despite a large increase in CORT immediately following IS, no associated change in CP was observed. In fact, the only significant change in CP was seen 7 days after IS, at a time when CORT was unchanged from control levels. These data raise questions about the general nature of the relationship between CORT and CP. They also suggest that, under some conditions, changes in hippocampal CP may emerge only after an "incubation period".