Semaglutide (sold as Ozempic, Wegovy and Rybelsus) was initially developed to treat diabetes. It works by stimulating the production of insulin to keep blood sugar levels in check.

This type of drug is increasingly being prescribed for weight loss, despite the fact it was initially approved for another purpose. Recently, there has been growing interest in another possible use: to treat addiction.

Anecdotal reports from patients taking semaglutide for weight loss suggest it reduces their appetite and craving for food, but surprisingly, it also may reduce their desire to drink alcohol, smoke cigarettes or take other drugs.

But does the research evidence back this up?

Animal studies show positive results

Semaglutide works on glucagon-like peptide-1 receptors and is known as a “GLP-1 agonist”.

Animal studies in rodents and monkeys have been overwhelmingly positive. Studies suggest GLP-1 agonists can reduce drug consumption and the rewarding value of drugs, including alcohol, nicotine, cocaine and opioids.

Out team has reviewed the evidence and found more than 30 different pre-clinical studies have been conducted. The majority show positive results in reducing drug and alcohol consumption or cravings. More than half of these studies focus specifically on alcohol use.

However, translating research evidence from animal models to people living with addiction is challenging. Although these results are promising, it’s still too early to tell if it will be safe and effective in humans with alcohol use disorder, nicotine addiction or another drug dependence.

What about research in humans?

Research findings are mixed in human studies.

Only one large randomised controlled trial has been conducted so far on alcohol. This study of 127 people found no difference between exenatide (a GLP-1 agonist) and placebo (a sham treatment) in reducing alcohol use or heavy drinking over 26 weeks.

In fact, everyone in the study reduced their drinking, both people on active medication and in the placebo group.

However, the authors conducted further analyses to examine changes in drinking in relation to weight. They found there was a reduction in drinking for people who had both alcohol use problems and obesity.

For people who started at a normal weight (BMI less than 30), despite initial reductions in drinking, they observed a rebound increase in levels of heavy drinking after four weeks of medication, with an overall increase in heavy drinking days relative to those who took the placebo.

There were no differences between groups for other measures of drinking, such as cravings.

In another 12-week trial, researchers found the GLP-1 agonist dulaglutide did not help to reduce smoking.

However, people receiving GLP-1 agonist dulaglutide drank 29% less alcohol than those on the placebo. Over 90% of people in this study also had obesity.

Smaller studies have looked at GLP-1 agonists short-term for cocaine and opioids, with mixed results.

There are currently many other clinical studies of GLP-1 agonists and alcohol and other addictive disorders underway.

While we await findings from bigger studies, it’s difficult to interpret the conflicting results. These differences in treatment response may come from individual differences that affect addiction, including physical and mental health problems.

Larger studies in broader populations of people will tell us more about whether GLP-1 agonists will work for addiction, and if so, for whom.

How might these drugs work for addiction?

The exact way GLP-1 agonists act are not yet well understood, however in addition to reducing consumption (of food or drugs), they also may reduce cravings.

Animal studies show GLP-1 agonists reduce craving for cocaine and opioids.

This may involve a key are of the brain reward circuit, the ventral striatum, with experimenters showing if they directly administer GLP-1 agonists into this region, rats show reduced “craving” for oxycodone or cocaine, possibly through reducing drug-induced dopamine release.

Using human brain imaging, experimenters can elicit craving by showing images (cues) associated with alcohol. The GLP-1 agonist exenatide reduced brain activity in response to an alcohol cue. Researchers saw reduced brain activity in the ventral striatum and septal areas of the brain, which connect to regions that regulate emotion, like the amygdala.

In studies in humans, it remains unclear whether GLP-1 agonists act directly to reduce cravings for alcohol or other drugs. This needs to be directly assessed in future research, alongside any reductions in use.

Are these drugs safe to use for addiction?

Overall, GLP-1 agonists have been shown to be relatively safe in healthy adults, and in people with diabetes or obesity. However side effects do include nausea, digestive troubles and headaches.

And while some people are OK with losing weight as a side effect, others aren’t. If someone is already underweight, for example, this drug might not be suitable for them.

In addition, very few studies have been conducted in people with addictive disorders. Yet some side effects may be more of an issue in people with addiction. Recent research, for instance, points to a rare risk of pancreatitis associated with GLP-1 agonists, and people with alcohol use problems already have a higher risk of this disorder.

Other drugs treatments are currently available

Although emerging research on GLP-1 agonists for addiction is an exciting development, much more research needs to be done to know the risks and benefits of these GLP-1 agonists for people living with addiction.

In the meantime, existing effective medications for addiction remain under-prescribed. Only about 3% of Australians with alcohol dependence, for example, are prescribed medication treatments such as like naltrexone, acamprosate or disulfiram. We need to ensure current medication treatments are accessible and health providers know how to prescribe them.

Continued innovation in addiction treatment is also essential. Our team is leading research towards other individualised and effective medications for alcohol dependence, while others are investigating treatments for nicotine addiction and other drug dependence.

Read the other articles in The Conversation’s Ozempic series here.

Shalini Arunogiri, Addiction Psychiatrist, Associate Professor, Monash University; Leigh Walker, , Florey Institute of Neuroscience and Mental Health, and Roberta Anversa, , The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This is the next article in our ‘Light and health’ series, where we look at how light affects our physical and mental health in sometimes surprising ways. Read other articles in the series.

It’s spring and you’ve probably noticed a change in when the Sun rises and sets. But have you also noticed a change in your mood?

We’ve known for a while that light plays a role in our wellbeing. Many of us tend to feel more positive when spring returns.

But for others, big changes in light, such as at the start of spring, can be tough. And for many, bright light at night can be a problem. Here’s what’s going on.

An ancient rhythm of light and mood

In an earlier article in our series, we learned that light shining on the back of the eye sends “timing signals” to the brain and the master clock of the circadian system. This clock coordinates our daily (circadian) rhythms.

“Clock genes” also regulate circadian rhythms. These genes control the timing of when many other genes turn on and off during the 24-hour, light-dark cycle.

But how is this all linked with our mood and mental health?

Circadian rhythms can be disrupted. This can happen if there are problems with how the body clock develops or functions, or if someone is routinely exposed to bright light at night.

When circadian disruption happens, it increases the risk of certain mental disorders. These include bipolar disorder and atypical depression (a type of depression when someone is extra sleepy and has problems with their energy and metabolism).

Light on the brain

Light may also affect circuits in the brain that control mood, as animal studies show.

There’s evidence this happens in humans. A brain-imaging study showed exposure to bright light in the daytime while inside the scanner changed the activity of a brain region involved in mood and alertness.

Another brain-imaging study found a link between daily exposure to sunlight and how the neurotransmitter (or chemical messenger) serotonin binds to receptors in the brain. We see alterations in serotonin binding in several mental disorders, including depression.

What happens when the seasons change?

Light can also affect mood and mental health as the seasons change. During autumn and winter, symptoms such as low mood and fatigue can develop. But often, once spring and summer come round, these symptoms go away. This is called “seasonality” or, when severe, “seasonal affective disorder”.

What is less well known is that for other people, the change to spring and summer (when there is more light) can also come with a change in mood and mental health. Some people experience increases in energy and the drive to be active. This is positive for some but can be seriously destabilising for others. This too is an example of seasonality.

Most people aren’t very seasonal. But for those who are, seasonality has a genetic component. Relatives of people with seasonal affective disorder are more likely to also experience seasonality.

Seasonality is also more common in conditions such as bipolar disorder. For many people with such conditions, the shift into shorter day-lengths during winter can trigger a depressive episode.

Counterintuitively, the longer day-lengths in spring and summer can also destabilise people with bipolar disorder into an “activated” state where energy and activity are in overdrive, and symptoms are harder to manage. So, seasonality can be serious.

Alexis Hutcheon, who experiences seasonality and helped write this article, told us:

[…] the season change is like preparing for battle – I never know what’s coming, and I rarely come out unscathed. I’ve experienced both hypomanic and depressive episodes triggered by the season change, but regardless of whether I’m on the ‘up’ or the ‘down’, the one constant is that I can’t sleep. To manage, I try to stick to a strict routine, tweak medication, maximise my exposure to light, and always stay tuned in to those subtle shifts in mood. It’s a time of heightened awareness and trying to stay one step ahead.

So what’s going on in the brain?

One explanation for what’s going on in the brain when mental health fluctuates with the change in seasons relates to the neurotransmitters serotonin and dopamine.

Serotonin helps regulate mood and is the target of many antidepressants. There is some evidence of seasonal changes in serotonin levels, potentially being lower in winter.

Dopamine is a neurotransmitter involved in reward, motivation and movement, and is also a target of some antidepressants. Levels of dopamine may also change with the seasons.

But the neuroscience of seasonality is a developing area and more research is needed to know what’s going on in the brain.

How about bright light at night?

We know exposure to bright light at night (for instance, if someone is up all night) can disturb someone’s circadian rhythms.

This type of circadian rhythm disturbance is associated with higher rates of symptoms including self-harm, depressive and anxiety symptoms, and lower wellbeing. It is also associated with higher rates of mental disorders, such as major depression, bipolar disorder, psychotic disorders and post-traumatic stress disorder (or PTSD).

Why is this? Bright light at night confuses and destabilises the body clock. It disrupts the rhythmic regulation of mood, cognition, appetite, metabolism and many other mental processes.

But people differ hugely in their sensitivity to light. While still a hypothesis, people who are most sensitive to light may be the most vulnerable to body clock disturbances caused by bright light at night, which then leads to a higher risk of mental health problems.

Where to from here?

Learning about light will help people better manage their mental health conditions.

By encouraging people to better align their lives to the light-dark cycle (to stabilise their body clock) we may also help prevent conditions such as depression and bipolar disorder emerging in the first place.

Healthy light behaviours – avoiding light at night and seeking light during the day – are good for everyone. But they might be especially helpful for people at risk of mental health problems. These include people with a family history of mental health problems or people who are night owls (late sleepers and late risers), who are more at risk of body clock disturbances.

Alexis Hutcheon has lived experience of a mental health condition and helped write this article.

If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14.

Jacob Crouse, Research Fellow in Youth Mental Health, Brain and Mind Centre, University of Sydney; Emiliana Tonini, Postdoctoral Research Fellow, Brain and Mind Centre, University of Sydney, and Ian Hickie, Co-Director, Health and Policy, Brain and Mind Centre, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.