Schizophrenia, which affects 20 million people globally according to the World Health Organisation, has been notoriously hard to treat. The mental health condition is characterised by distortions in cognition, perception, emotions, sense of self, and behaviour.

Common experiences include what is termed as 'positive symptoms', namely delusional thoughts and visual and auditory hallucinations, and ‘negative symptoms’ such as social withdrawal, lack of motivation, and cognitive impairment.

Currently, antipsychotic medications are clinically proven to be effective at reducing the ‘positive symptoms’ but less so at treating the ‘negative symptoms’.

While the exact causes of schizophrenia are unknown, it is theorised to occur when a region of the brain that plays a central role in cognitive functions, the prefrontal cortex, becomes abnormally active due to a dysfunction of regulating interneurons.

Researchers at the American Vanderbilt University have sought to develop a new innovative treatment that effectively treats both the 'positive and negative symptoms' by modulating the activity of those brain cells.

New treatments are being led by neuroscience

After identifying the neurotransmitter mGlu1 as a target of study, researchers tested a compound that enhances its function: a positive allosteric modulator (PAM). The compound, researchers found, can increase the activity of inhibitory interneurons and, as a result, reduce abnormal brain activity.

In trials, the team also discovered that the PAM compound reversed the ‘positive symptoms’ of schizophrenia, as well as showed promise in treating some of the ‘negative symptoms’.

Researcher James Maksymetz explained: “We reasoned that if we addressed the underlying disease biology by boosting the function of these interneurons, then we might be able to rescue cognitive deficits associated with prefrontal cortex dysfunction.”

Mr Maksymetz added that the study is particularly exciting as the drug reverses working memory deficits, a hallmark of schizophrenia for which there is no treatment.

The result of this study is based on decades of clinical findings which have improved clinicians understanding of the biology of schizophrenia. Today’s pharmaceutical treatments were discovered half a century ago; it is hoped that contemporary neurobiological knowledge will lead to improved medical interventions.

Mr Maksymetz commented: “Hopefully, we will be able to test the hypothesis that mGlu1 PAMs can actually treat patients with schizophrenia someday soon. I truly believe that understanding how neural circuits function and dysfunction will lead to a revolution in treating neuroscience-related diseases, and I'm excited to be a part of it."