Biomarker Discovery and Gene Mutation Research Offer New Hope for Schizophrenia Treatment

Researchers have identified a biomarker linked to schizophrenia that could lead to new treatments for symptoms of the mental disorder not addressed by current medicines. Analyzing cerebrospinal fluid samples from over 100 people with and without schizophrenia, scientists found that those with the disorder had significantly lower levels of a brain protein called CACNA2D1 compared to healthy individuals.

Low levels of CACNA2D1, they said, led to overstimulation of the brain's electrical networks, which in turn contributed to cognitive impairment. The researchers created a synthetic version of the protein and tested it in a mouse model of genetic schizophrenia. A single injection into the animals' brains corrected both the abnormal brain circuit activity and the behavioral problems linked to the disorder, without negative side effects such as sedation or reduced movement, they reported in Neuron. Currently available antipsychotic drugs can help to control a patient's hallucinations and delusions, but they do not improve cognitive issues like disorganized thinking and executive dysfunction, which can often prevent individuals from living independently. According to the researchers, the discovery could establish the basis of a "revolutionary and completely novel treatment strategy through a tandem biomarker-peptide therapeutic approach," and the next step would be to identify the human patients who could respond and treat them accordingly.

In a separate line of research, a newly identified gene mutation may help explain why schizophrenia patients struggle to update their understanding of reality. The mutation occurs in a gene called grin2a, which had previously been flagged in large genetic studies of schizophrenia. The mutation disrupts a brain circuit involved in flexible decision-making, causing mice to stick with outdated choices even when conditions change. Researchers pinpointed the issue to a key thalamus–prefrontal cortex pathway. By reactivating this circuit, they were able to restore normal behavior—raising hope for future therapies. The study appears in Nature Neuroscience. Schizophrenia has a strong genetic component: in the general population, about 1 percent of people develop the condition; that risk increases to 10 percent if a parent or sibling is affected, and rises to 50 percent for identical twins. By analyzing around 25,000 sequences from people with schizophrenia and 100,000 from control subjects, the team identified 10 genes where mutations significantly increase the risk of developing the disorder.

For more than 70 years, the drug treatments available to psychiatrists to help their patients with schizophrenia have barely changed – they all work through the same mechanism in the brain, with the same drawbacks and limitations. Dopamine-blocking antipsychotic drugs are highly effective in decreasing psychotic symptoms, such as delusions and hallucinations, but they have no effect on the social withdrawal also seen in schizophrenia or on difficulties in cognition, and they cause significant side-effects, including weight gain and worsening fat and sugar levels in the blood. A new type of antipsychotic medication with a totally different mechanism of action has now been developed and is becoming available to patients. This treatment does not target the dopamine system but instead modulates signalling by another chemical system in the brain – the cholinergic system.