Reckless, impulsive, dependent: when your medication makes you not yourself

By Saarah Chowdhury 

What happens when medication causes harmful behavioural change, and what happens when that link isn’t detected for years? Blame can be placed on the patient, the medication, or any of the systems that join the two together; however, there are many instances of the former bearing the burden for far too long.

“Prescription medication made me a gambling addict,”² and “doctors didn’t warn women of ‘‘risky sex” drug urges,”¹ are two of a series of articles published by the BBC this year that tell the stories of patients who had been prescribed dopamine agonists and whose ensuing behaviour changes have “ruined their lives”¹.

Dopamine is a neurotransmitter involved in regulating movement, and therefore dopamine agonists are used in treating motor symptoms of Parkinson’s Disease and restless leg syndrome (RLS). However, dopamine is also commonly referred to as the ‘happy hormone’ due to its role in our brain’s reward circuits. There is a well-documented link between the prescription of dopamine agonists and the development of impulse control disorders, impacting an estimated 6 to 17% of people with RLS and up to 20% of those with Parkinson's who take dopamine agonists. Impulsive control disorder can manifest in many forms such as compulsive shopping, gambling addiction or ‘risky’ sexual behaviour. These not only harm the patient, but can have detrimental impact on those around them, particularly in cases where criminal sexual behaviours have been linked to concurrent dopamine agonist use.³ 

While this connection has been known since the development of this class of drugs by GSK in the early 2000s, there have been many cases of patients not being well-informed of this side-effect, leading to multiple lawsuits against GSK¹ and cases of legal action against prescribing doctors². Patients spend years unable to link drastic changes in their behaviour to their medication, largely because they were neither warned nor monitored for these side effects.

A woman who developed a severe gambling addiction that led to her losing £80,000, which had a “horrific” effect on her family, said that: “at the time I didn't know it was no fault of my own."¹ Discovering the link is crucial, not only because most dopamine agonist-induced impulse control disorders improve when the medication is stopped, but also because it can alleviate much of the guilt and blame carried by those who had believed the impulsive behaviour was entirely their own.

There are also wider benefits to identifying these kinds of side-effects as medication-related, particularly when responsibility can be traced back to regulatory failures. A key example of this is the opioid crisis in the USA. 

In 1996, Purdue Pharma introduced Oxycontin, a branded and slow-release version of oxycodone, an opiate used for pain relief. They revolutionised the pain relief market by marketing a drug formerly used to treat end-of-life or cancer-related pain for more widespread ailments such as chronic back pain or headaches.⁴

The accusation levelled by thousands of lawsuits against Purdue and its owners, the Sackler family, is that they used misleading marketing and downplayed concerns about addiction to encourage doctors to prescribe more of the drug. This led thousands to become addicted and for their lives to fall apart due to dependence on opioids. Even if their prescription was stopped, the experience of unsupported opioid withdrawal, with manifestations such as muscle pain, vomiting and anxiety, caused some people to turn to black market prescription opioids or, a far cheaper alternative, heroin⁴. The opioid crisis has therefore been described not only as the cause of many deaths through overdose, but the cause of family breakdown⁵, homelessness⁶, and criminal behaviour⁷.

The Sacklers have also been accused of shifting blame onto those who became addicted by presenting them as individuals who abused an otherwise not particularly addictive drug. A reported email by Richard Sackler said: “We have to hammer on the abusers in every way possible. They are the culprits and the problem. They are reckless criminals.”⁸

In 2022, the Sackler family was ordered by the US Supreme Court to pay $6 billion for their role in the USA’s opioid epidemic, in which millions became addicted and nearly 500,000 people died from overdoses between 1999 and 2019. The Sacklers have been so widely blamed for the opioid crisis that institutions such as the Louvre and the Tate galleries have removed their name from sponsored exhibition halls.¹²

While a scandal on this scale has not been uncovered with dopamine agonists, GSK did settle a class action lawsuit against them for failing to include any warnings of impulsive behaviour in dopamine agonist product information until 2007. This is despite the link being established in studies as early as 2000, although they denied liability.¹

Viewing addiction through a purely biochemical lens moves blame away from those who become dependent on opioids, recognising instead that these drugs are incredibly addictive. The body rapidly develops tolerance to opioids and requires ever-increasing doses to achieve the same pain relief or euphoric effect. However, it is not just an unfortunate complication of drug mechanisms that led to the opioid crisis. The Sacklers and Purdue Pharma have been found to be blame-worthy, and a privatised healthcare system and inadequate regulation by the American Food and Drug Administration have also been found to have played major roles.⁹

Even if just the biochemical link between dopamine agonist therapy and developing an impulse control disorder was found with no broader factors or conclusions uncovered, it would be valuable through providing clarity and relieving blame faced by sufferers. It is one of the many trade-offs made in medicine that dopamine agonists are able to counter the symptoms of debilitating diseases like Parkinson’s or RLS, but have this additional potential impact. The trade-off is so difficult to weigh up that some continue their treatment despite developing impulse control disorder. However, to see this as an inevitable side-effect, that will go on to greatly harm the quality of life of a certain percentage of dopamine agonist users, should not be viewed as a foregone conclusion.

This August, the Royal College of General Practitioners changed their guidelines to shift dopamine agonists from first to second line for RLS¹, and advise monitoring of impulsive behaviour side effects³. The Parkinson’s Foundation has extensive advice on pre-emptively managing the development of impulse control issues, such as keeping a ‘drug diary’ to record changes in mood or behaviour. The strongest measure they recommend is to have a prospective monitoring plan in which you consent to a family member or friend being able to provide information about behaviour changes to your doctor¹⁰. Principles of personalised and preventative medicine can also be enabled by research that develops our understanding of risk factors for development of ICDs secondary to dopamine agonist use¹¹. 

Stories such as those highlighted in the BBC are not inevitable, and could have been prevented through improvements to regulatory systems and clinical practice. However, those patients were left with years in which they were unable to recognise the connection between their unwanted behaviour and their medication. Both biochemical forces and systemic failures can work against patients in ways that lead to blame and guilt being solely, and wrongly, placed on them; the importance of identifying when this happens extends far beyond the scope of medication side-effects. 

Read the rest of the edition here

References 

1. Titheradge N, Lancaster C. Doctors didn’t warn women of “risky sex” drug urges. BBC News [Internet]. 2025 Mar 11; Available from: https://www.bbc.co.uk/news/articles/cgkmrev6z2mo
2. Lancaster C. Ropinirole: “Prescription medication made me a gambling addict.” BBC News [Internet]. 2025 Mar 12; Available from: https://www.bbc.co.uk/news/articles/cjw24p7jpgjo
3. Titheradge N. “My dad started spying on my mum” - the drugs causing sexual urges. BBC News [Internet]. 2025 Jul 26; Available from: https://www.bbc.co.uk/news/articles/cpqnpryxvrro
4. Gross T. Journalist Investigates “Crime Story” Of The Sackler Family And The Opioid Crisis. NPR [Internet]. 2021 Apr 14; Available from: https://www.npr.org/2021/04/14/986736258/journalist-investigates-crime-story-of-the-sackler-family-and-the-opioid-crisis
5. Rappleye H, Breslauer B. Opioid Crisis Forces Grandparents to Raise Their Grandkids [Internet]. NBC News. 2017 [cited 2025 Nov 30]. Available from: https://www.nbcnews.com/storyline/americas-heroin-epidemic/opioid-crisis-forces-grandparents-raise-their-grandkids-n808991
6. Opioid Abuse and Homelessness [Internet]. National Alliance to End Homelessness. 2024. Available from: https://endhomelessness.org/resources/policy-information/opioid-abuse-and-homelessness/
7. Humphreys K, Shover CL, Andrews CM, Bohnert ASB, Brandeau ML, Caulkins JP, et al. Responding to the opioid crisis in North America and beyond: recommendations of the Stanford–Lancet Commission. The Lancet. 2022 Feb;399(10324):555–604.
8. Dearbail J. Is this America’s most hated family? BBC News [Internet]. 2019 Mar 22; Available from: https://www.bbc.co.uk/news/business-47660040
9. Gapper J. Empire of Pain — the story of the Sacklers and OxyContin [Internet]. www.ft.com. 2021. Available from: https://www.ft.com/content/1db7800f-78d5-474e-9b1e-744b1c1a837c
10. Impulse Control | Parkinson’s Foundation [Internet]. www.parkinson.org. Available from: https://www.parkinson.org/library/fact-sheets/impulse-control
11. Grall-Bronnec M, Victorri-Vigneau C, Donnio Y, Leboucher J, Rousselet M, Thiabaud E, et al. Dopamine Agonists and Impulse Control Disorders: A Complex Association. Drug Safety. 2017 Aug 31;41(1):19–75.
12. Sackler family to pay $6bn for role in US opioid crisis. BBC News [Internet]. 2022 Mar 3; Available from: https://www.bbc.co.uk/news/world-us-canada-60610707