New Study Uncovers Surprising Role of Serotonin in Worsening Schizophrenia Symptoms

A recent study has found that increased serotonin activity in specific brain regions may play a crucial role in exacerbating negative symptoms of schizophrenia, hindering patients' recovery and social integration.

Schizophrenia is a complex mental disorder affecting approximately 1% of the global population, with key negative symptoms including social isolation, lack of motivation, anhedonia, and diminished capacity to engage in daily activities.

Despite advancements in medication, these symptoms remain some of the most challenging to treat.

For the first time, researchers from the Institute of Psychiatry, Psychology & Neuroscience at King's College London tested a hypothesis proposed over sixty years ago, suggesting that hyperactivity of the serotonergic system could contribute to these symptoms. The study involved 54 participants, including 26 diagnosed with schizophrenia and 28 healthy controls.

Participants underwent two positron emission tomography (PET) scans, using a radioactive substance that binds to serotonin receptors in the brain.

Between the scans, participants received a dose of d-amphetamine to stimulate serotonin release.

Results indicated a general decrease in the binding of the radioactive substance to serotonin receptors across all participants, suggesting an increase in serotonin release. However, this increase was significantly more pronounced in patients with schizophrenia, particularly in the prefrontal cortex, which is responsible for planning, decision-making, and motivation.

Analysis also revealed that the heightened serotonin release was directly correlated with the severity of negative symptoms and the level of dysfunction in patients, indicating a potential role of this neurotransmitter in complicating the disease's trajectory rather than improving it, challenging the common perception of serotonin as the "happiness hormone."

While serotonin is known for its central role in mood regulation, sleep, cognitive functions, appetite, and social behavior, this study highlights that its imbalance, rather than merely its reduction, could be a pathological factor in certain mental disorders.

Researchers believe these findings could pave the way for new therapeutic strategies aimed at more precisely regulating serotonin activity, rather than simply increasing it, which may help improve the quality of life for individuals with schizophrenia in the future.