Neurostimulation-enhanced Behavioural Remediation of Social Cognition in Schizophrenia (NERS-SC)

Schizophrenia is a mental illness affecting roughly one percent of the population worldwide. One of its most enduring and debilitating aspects is the effect that it has on patients’ ability to participate in society, in their family life, their social life, and their employment. To function effectively requires that we are able to recognise cues to other people’s mental state of mind. Indeed, understanding people’s intentions is crucial for our wellbeing. Impairments in these skills can compromise quality of life, the ability to live independently, and the ability to plan and alter basic daily activities.

This study aims to test a new mechanism by which impaired social inferences might develop, based on evidence of the problems that patients with schizophrenia have processing information from our senses. In particular, the aim is to test how distorted time perception and impaired judgements of causality contribute to misunderstandings of social intentions. Here ‘physical causation’ refers to the relation between an event (the cause) and a second event (the effect), where the second event is a physical consequence of the first. We propose that in the brain, incorrect coding of the perception that two events occurred simultaneously by people with schizophrenia, transmits unreliable information about causal relations between events, which can then lead to a misunderstanding of social intentions.

To achieve this aim, we will compare how people with schizophrenia perform against how healthy adults without schizophrenia perform, in a two-part study. In the first visit, we will ask participants to perform tests of basic time perception, a test of the ability to judge causality based on the timing of events, and a test of the extent to which the ability to judge events as simultaneous is used to infer causality in a social situation. In this first visit, we will also assess psychological well-being and severity of clinical symptoms, and record the patterns of electrical activity in the brain during time perception. At the second visit, we will employ non-invasive brain stimulation to test a possible mechanism by which time perception is linked to the making of social inferences, and to evaluate whether this technique can be used to boost patients’ performance. The brain stimulation will be partnered with simple training exercises previously shown to sharpen perception of time. By targeting the brain stimulation and training exercises at time perception, we should subsequently observe improvements in the ability of patients with schizophrenia to use timing-related information to make social inferences. At visit 2, the recordings of electrical brain activity will be repeated, to test whether our intervention works by sharpening the neural mechanisms responsible for timing perception.

In the future, the results of this study could be harnessed to treat abnormalities in the perception of sensory time cues, before processing has even progressed to any inference of social intent. Once fully developed, the time perception training with or without enhancement from the brain stimulation, would be easy and quick to implement.

Researchers: Rachel Mitchell, Sukhi Shergill