Yoga therapy for social cognition in schizophrenia: An experimental medicine-based randomized controlled trial

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Highlights

Abstract

Negative symptoms and cognitive deficits are difficult-to-treat symptoms of schizophrenia. In this single blind randomized controlled study, we compared change in social cognitive performance in persons with Schizophrenia (PWS) (as per DSM-5), after 6 weeks of yoga intervention with a waitlist control group. We also examined changes in putative Mirror Neuron System (MNS) activity measured by Transcranial Magnetic Stimulation (TMS) in a subset of sample (n = 30). 51 PWS stabilized on antipsychotic medication for at least 6 weeks, were assigned to add-on yoga therapy (YT) (n = 26) or waitlist (WL) (n = 25). Subjects in the YT group received add-on yoga therapy (20 sessions in 6 weeks). Both the groups continued their standard treatment and were assessed at baseline and after 6 weeks for social cognition, clinical symptoms and social disability. RM-ANOVA showed significant interaction between time and group for social cognition composite score (SCCS) (F = 42.09 [1,44], P < 0.001); negative symptoms (SANS) (F = 74.91 [1,45], P < 0.001); positive symptoms (SAPS) (F = 16.05 [1,45], P < 0.001) and social disability (GSDS) (F = 29.91 [1,46], P < 0.001). MNS activity had increased after 6 weeks in both groups but not of statistical significance. This study demonstrates that 6 weeks of add-on yoga therapy could improve social cognition in PWS compared to waitlist control subjects. However, the change in social cognition was not associated with a change in the putative MNS-activity. It necessiatates further studies to investigate the mechanistic processes of yoga and replicate these observations in a larger sample.

Introduction

Schizophrenia is characterized by three important symptom clusters namely positive, negative & cognitive symptoms. Persons with schizophrenia (PWS) often seek treatment for positive and negative symptoms. However, cognitive deficits are much earlier to occur and has more debilitating effects on functional outcome. Broadly cognitive symptoms could be classified as neurocognition or social cognition deficits. Neurocognition (non-social) and social cognition are two related yet distinct latent dimensions of cognitive symptoms in schizophrenia (Mehta et al., 2013), both of which have a substantial inter-dependent impact on real-world functional outcomes (Fett et al., 2011). Social cognition is defined as mental operations that underlie social interactions(Brothers, 1990). Most frequently studied aspects of social cognition in schizophrenia are Theory of Mind (ToM), Emotion processing (EP), Social perception (SP), Social knowledge, and Attribution Style (AS) (Couture et al., 2006; Penn et al., 2008). Except for the positive symptoms, there are no effective treatments available for the negative and cognitive symptoms including social cognition deficit (Buckley and Stahl, 2007) In addition, the existing treatments are not free of side effects; some causing extrapyramidal side effects and others causing metabolic side effects.(Abbott, 2010)

Psychosocial interventions are available targeting a few or most of the domains of social cognition with or without neurocognition training. But the majority of them [for example, Cognitive Enhancement Therapy (CET), Social Cognition Interaction Training (SCIT)] are highly resource-intensive and their feasibility in developing countries is questionable. Moreover, they were developed keeping the western patient population in mind and their cultural validity in other cultures is questionable. In addition, the magnitude of benefits following such interventions is variable (effect sizes range between 0.30–1.29) (Kurtz et al., 2016), and their generalizability to improvements in functional outcomes is minimally evaluated. Hence, there is a need to explore the role of other complementary therapies like yoga, ayurveda, homeopathy, and music therapy for an indigenous, integrated approach in treating PWS. Among the complementary therapies, Yoga is unique in following an integrated approach engaging body, breath & mind unlike others.

In healthy adults and the elderly, yoga is found to be efficacious in improving cognitive skills (Gothe and McAuley, 2015). As an add-on treatment, yoga is more effective than physical exercise in reducing the negative symptoms in PWS (Duraiswamy et al., 2007; Varambally et al., 2012). It also improves the quality of life in PWS (Cramer et al., 2013; NICE, 2014), More recent studies have examined the therapeutic effects of yoga on neurocognition and reported cognitive gains in PWS (Bhatia et al., 2017). Interestingly two randomized controlled trials (RCT) have demonstrated improvement in Emotion Processing(EP)- an important domain of social cognition (Behere et al., 2011; Jayaram et al., 2013). One of these studies had also reported enhanced plasma oxytocin in PWS following yoga intervention (Jayaram et al., 2013). In a recent double-blind RCT, intranasal administration of oxytocin has been shown to increase the activity of putative Mirror Neuron System (MNS) in social contexts (Festante et al., 2020). Imitation and being imitated are also associated with an increase in oxytocin (Delaveau et al., 2015). This principle of practicing imitation & being imitated are integrated into yoga training during group supervision. Recently, Insel proposed investigating the biological mechanisms along with the clinical efficacy is imperative. (Insel, 2015). Hence our study adopted the experimental medicine-based approach for simultaneous investigation of the effect of add-on yoga therapy on social cognition and the underlying putative biological mechanism in PWS. To the best of our knowledge, there is no study that has examined the putative biological mediators of therapeutic gains following yoga practice.

In this study, we aimed to

  • a)

    Compare changes in comprehensive measurements of social cognition [encompassing theory of mind (ToM), emotion processing (EP), social perception (SP), attribution style (AS)] in PWS assigned to add-on yoga therapy (YT) or waitlist (WL) groups.

  • b)

    Examine changes in putative MNS activity measured by Transcranial Magnetic Stimulation (TMS) between YT and WL groups.

We hypothesized that the practice of 20 sessions of yoga in six weeks would improve social cognition composite score in PWS. Our secondary hypothesis was MNS activity would also increase after 20 supervised yoga therapy sessions in PWS.

Section snippets

Study participants

We conducted an RCT with PWS (N = 51) at a tertiary care neuropsychiatry hospital in south India in collaboration with a yoga university. Both inpatients (n = 11) and outpatients (n = 40) seeking treatment at the hospital were diagnosed by a qualified psychiatrist as per DSM-5 (American Psychiatric Association, 2013) guidelines and confirmed with Mini-International Neuropsychiatric Interview (M.I.N.I.) (Sheehan et al., 1998). Eligible and willing subjects were recruited after obtaining written

Results

The trial profile is depicted in the CONSORT flowchart in Fig. 1.

Out of 581 subjects screened, 402 were eligible and 51 subjects agreed to participate in the study with randomization to Yoga therapy or a waitlist group. At the end of the trial, 24 subjects were available in the yoga group & 22 subjects in the waitlist group for analysis.

Discussion

This is one of the first studies exploring the role of yoga in social cognition mediated by MNS activity. Previous studies (Jayaram et al., 2013; Behere et al., 2011) have shown that yoga improves Facial Emotion Recognition Deficit (FERD) in PWS. In the current study, social cognition was measured as a composite score which included comprehensive coverage of ToM (1st order and 2nd order), FERD, Social Perception, and Attribution Style (AS) besides facial emotion recognition deficit (FERD).

Funding

This research received no specific grant from any funding agency, commercial or not-for-profit sectors.

Transparency document

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Declaration of Competing Interest

The authors report no declarations of interest.

Acknowledgement

The authors would like to acknowledge the participants and the wider study team. Dr Mehta is supported by the Wellcome Trust/DBT India Alliance Early Career Fellowship, Grant/Award Number: IA/E/12/1/500755. Dr Varambally is supported by the Wellcome Trust/DBT India Alliance Intermediate Fellowship, Grant/Award Number: IA/CPHI/15/1/502026.

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