Patients who are prescribed a common antipsychotic used to treat depression, bipolar disorder, psychosis and schizophrenia need to be told there is a risk they could develop a gambling addiction, an expert has warned.

The National Problem Gambling Clinic has observed growing numbers of patients who have developed a gambling addiction after starting to take aripiprazole. Some patients have lost huge sums of money as a result and seen their relationships fall apart.

Prof Henrietta Bowden-Jones, a leading psychiatrist who runs the clinic, said more awareness needed to be raised, as patients were not being warned by many GPs prescribing the drug, and mental health teams were failing to monitor whether people were developing addictions.

“This is not just any side-effect – it can come with a risk of losing your own home. What we constantly see is that not enough people know about this. I gave a recent lecture to all the psychiatrists in my trust and a very large proportion had never heard about it,” she said. “We constantly hear about mental health teams not being aware. More needs to be done to prevent people from being put on aripirazole without being warned and monitored.”

The National Problem Gambling Clinic’s audit of its patients for 2022 found that nearly 9% were taking the drug, or 30 out of 359. Bowden-Jones said they typically were not aware of the connection between aripiprazole and problem gambling.

GPs receive alerts of side-effects when they prescribe drugs, but although pathological gambling is listed as a side-effect by the National Institute for Health and Care Excellence, it is not flagged. Mental health teams in psychiatric units often help monitor patients taking the drug, but are not specifically looking out for warning signs of problem gambling.

There is government guidance for GPs to inform patients of the link between Parkinson’s medication and gambling addiction and to monitor it.

Doctors should should be mindful that stigma and shame often prevents people reporting symptoms of gambling harm, and look out for whether aripiprazole results in other compulsive behaviours, for example excessive drinking, drug-taking, sex or shopping, added Bowden-Jones.

Lee Jordan developed a gambling addiction after taking aripiprazole in 2021 to ease psychosis symptoms, including hearing voices, which developed during a highly stressful period of work. While he had gambled small amounts of money for fun in the past, his casual habit quickly started to take over his life.

“I was spending a huge amount of money because it was a release. But the devastating effects were humungous – I nearly lost my relationship, I lost family, friends, it just destroyed my life really,” he said, adding that he had lost £10,000 to gambling companies and been unable to recoup the money.

Jordan came off aripiprazole in 2022 and within weeks, he felt empowered to stop gambling. “When I came off the medication it was a struggle for a little bit, because it was ingrained in my brain those endorphins for the wins. There were cravings afterwards, and I was able to install Gamban [gambling blocking software] on devices, but I needed a bit of willpower – you’ve got to want to give up. With the added pressure of aripirazole gone, it was easy for me to accomplish that goal.”

Jordan is now on antidepressants, but will begin a new course of antipsychotics soon, as he still hears voices intermittently, although he will not take aripiprazole again. “It’s a catch-22 – do you want to take it because you want to stop hearing voices, or do you want to keep damaging and ruining your life, and become homeless?”

Paul Kanolik, a lawyer at Ellis Jones specialising in gambling cases, said it was “quite staggering” how many people with psychiatric illnesses he was seeing ending up with thousands of pounds of gambling debt. While he has won some cases, he said current legislation was a “grey area”, which needed to be overhauled to better protect vulnerable people, especially given the accessibility of online gambling.

The Medicines and Healthcare products Regulatory Agency said pathological gambling and other impulse control disorders were “a well-recognised side-effect of aripiprazole”, which are listed as side-effects in the patient information leaflet. The MHRA recommends that patients and doctors always discuss the benefits and risks of any medication.