A medicine already used to treat malaria could also work as a treatment for polycystic ovary syndrome (PCOS).

In a small trial of 19 women with PCOS, the widely used drug artemisinin improved the regularity of their menstrual cycles and lowered their testosterone, which is often too high in people with the condition.

While the root cause of PCOS is unclear, it involves imbalances in several hormones, including too much testosterone being made by the ovaries. This can lead to irregular menstrual cycles and infertility, as well as acne and excess body hair, among other symptoms.

Those affected also tend to be less sensitive to the sugar-regulating hormone insulin, which leads to weight gain, worsening the hormone imbalances.

At the moment, people with PCOS have their symptoms treated individually. For instance, they might have laser treatments to remove body hair or take the contraceptive pill to regularise menstruation.

While investigating the effects of different drugs on fat cells in mice, at Fudan University in Shanghai, China, noticed that artemisinin reduced symptoms in mice with a condition similar to PCOS.

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His team later gave artemisinin to 19 women with PCOS for three months. It lowered levels of testosterone in all of them, and most also saw a decrease in another substance called anti-MĂĽllerian hormone, . For 12 of the participants, the drug also led to regular menstrual cycles.

In other work in mice and in human cells, the team found that artemisinin seems to reduce testosterone production in the ovaries.

at Imperial College London says artemisinin could act through a different mechanism by improving insulin sensitivity, as losing weight tends to reduce PCOS symptoms, although the 19 women had a healthy body mass index on average. “If the results are as good in a randomised trial as in this preliminary study, it’s exciting,” he says.

at the Karolinska Institute in Stockholm, Sweden, says the fact that artemisinin is already generally safe when used for malaria means it could be quickly turned into a new treatment for PCOS.

Ancient viruses embedded in human DNA millions of years ago may play a role in raising people’s risks of depression, schizophrenia and bipolar disorder. The viral genes have unusual activity levels in people who have a higher genetic risk of experiencing these mental health conditions, a study has found.

Retroviruses are a large group of viruses whose life cycle involves inserting their genetic information into the DNA of their host. Remnants of such viral genes can be seen in the DNA of many animal species, and these sequences are called human endogenous retroviruses (HERVs) when found in the human genome.

Until recently, most HERVs were thought to remain dormant and were called “fossil viruses”. But previous studies have suggested that some of the viral genes may in fact be active – although not producing infectious viruses – and may even play a role in neurological conditions,

In a new study, at King’s College London and his colleagues investigated the possible role of these viral remnants in mental health conditions by looking at viral proteins in nearly 800 brains that had been donated for medical research.

While the team didn’t record if any of the donors had been diagnosed with mental health conditions while alive, they found that some genetic variants that are known to raise the risks of depression, schizophrenia and bipolar disorder were associated with altered activity of genes from five different HERVs.

It wasn’t possible to estimate how much of a raised risk was linked with the unusual viral gene activity, but it is probably in the range of a few per cent, as most human gene variants affect psychiatric risk by such small amounts, says Powell.

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The findings also don’t necessarily mean that the altered HERV activity is causing the conditions – it could be a consequence, he says.

“The methods used look pretty robust,” says at the University of Nottingham in the UK. “The results are likely real that these things are markers of these diseases, but [the researchers] are rightly cautious in saying they don’t know what that means.”