According to a number of recent studies, semaglutide weight-loss drugs can be effective in treating depression, anxiety, dementia, addiction and some eating disorders.

There is a great deal of research, and more ongoing, which shows the broad-ranging benefits of weight loss drugs, which could potentially lead to them being prescribed for a range of illnesses in the future.

The drugs work for weight loss by mimicking the hormone, glucagon-like peptide-1 (GLP-1), which is produced by the gut and brain, and leads to an increased feeling of satiety. As GLP-1 receptors are peppered throughout the brain – including areas important for cognitive functions and emotional control, such as the prefrontal cortex, hippocampus and amygdala – research shows that stimulating these receptors could be beneficial for other health issues too.

Rodrigo Mansur, from the University of Toronto, led a small study giving liraglutide to 19 people with major depressive disorder or bipolar disorder and within a month they reported better mood, attention span and cognitive function. MRI scans of the participants’ brains revealed that the areas involved in planning, organisation and emotional processing significantly increased in volume within a month. Mansur is now conducting a randomised controlled trial to investigate the ability of GLP-1 drugs to directly treat mood disorders.

GLP-1 has also been shown to increase the brain’s blood flow, slow down the death of nerve cells and promote the flow of glucose to the brain, which is an incredibly sugar-hungry organ, consuming up to 20 per cent of calories. Some studies show that GLP-1 modulates the transport of glucose across the blood-brain barrier, slows the rate at which the brain consumes glucose, reduces oxidative stress and damps down inflammation, which leads to cardiovascular benefits.

Some studies have shown benefits of treating brain diseases, such as Parkinson’s and Alzheimer’s, which are characterised by neuroinflammation. Pharmaceutical company, Novo Nordisk, is currently working on two trials testing semaglutide for Alzheimer’s disease. There is hope these drugs could also help other brain conditions, such as epilepsy and stroke.

A study at Penn State Neuroscience Institute used anti-obesity drugs to treat opioid addiction and found a 40 per cent reduction in opioid cravings over three weeks compared with those receiving a placebo. Researchers suspect the drugs target addiction in a similar way to hunger drive, by influencing the two areas of the brain involved with reward processing and cravings. A larger trial is now underway.

Last year, University of Oklahoma found that semaglutide was more effective in helping people with binge eating disorder than the only medication currently approved by the US Food and Drug Administration (FDA) for this condition. Other evidence suggests that GLP-1s might also help treat bulimia nervosa, an eating disorder which presents as bingeing and purging.

However, there are a few snags with what appears to be a wonder drug. Widespread use of weight-loss medication might lead to further idealisation of slim bodies. It is not yet known if people who aren’t overweight can take GLP-1s safely for mental health reasons alone, as reducing their appetite could lead to malnourishment or becoming critically underweight. For this reason they are not suitable for people suffering from the eating disorder, anorexia nervosa, even though it often stems from anxiety and is an addiction to restricting food.

The research studies have been published in New Scientist magazine.