Statins, commonly used to combat physical health diseases, could bring significant benefits to people with serious mental illnesses such as schizophrenia, bipolar disorder or non-affective psychoses.

A large cohort study led by UCL, published in JAMA Psychiatry, has found that exposure to any of the study drugs was associated with reduced rates of psychiatric hospitalisation compared with unexposed periods.

Self-harm was reduced in patients with bipolar disorder and schizophrenia during exposure to all study drugs and in patients with non-affective psychosis taking L-type calcium channel antagonists.

In some cases, rates of self harm diminished by more than 40% for those taking statins or blood pressure drugs, and more than 30% for patients on diabetes drugs.

The investigation used 142,691 patients’ data and focused on patients who had either been prescribed statins to reduce cholesterol/heart disease, L-type calcium channel antagonists (LTCC), to reduce high blood pressure, or biguanides (such as metformin), to treat diabetes.

The patients' health records relating to self-harm and psychiatric hospitalisation were assessed as to whether these episodes occurred during a period when patients were taking the prescribed medication or in periods when they were not.

Lead author, Dr Joseph Hayes of UCL Psychiatry, said: "Serious mental illnesses, including bipolar disorder, are associated with high levels of morbidity and are challenging to treat.

"Many widely used drugs, such as statins, have long been identified as having the potential for repurposing to benefit these disorders.

"This study is the first to use large population data sets to compare patient's exposure to these commonly used drugs and the potential effects on people with serious mental illnesses."