Whose Behaviour Is It? Pharmacological Coercion and the Myelinated Self

Dr Jack Parry 2 May 2026

keywords: dopamine agonist Parkinson’s restless legs compulsive behaviour impulse control legal responsibility pharmaceutical pharmacological coercion myelin accumulated condition Sally Gardner

Sally Gardner is the author of Maggot Moon, winner of the Carnegie Medal, with 2.5 million books sold. Before her career took off she had been prescribed dopamine agonist medication for restless legs syndrome, a condition that made it impossible to sit still in the evenings, that had caused years of chronic sleeplessness, and that had no other treatment that worked for her. The drug relieved her symptoms immediately.

Over the following years she spent more than £500,000 she did not have. A £3,000 bathtub. Prints by Peter Blake. Trips to Parisian boutiques. The same pair of shoes bought five times. Ten separate dog beds for a Yorkshire Terrier. She sold her north London townhouse and moved to a smaller flat, then spent tens of thousands of pounds having an interior designer decorate it. A friend walked from shop to shop in the town where she lived, begging staff not to sell anything to her.

Sally thought she was going mad. She had no explanation for behaviour she experienced as entirely compulsive and entirely alien to her character. “Who are you?” she asked herself. “What are you doing?”

Twenty years later, after listening to a BBC podcast series about dopamine agonist side effects, she understood what had happened. The medication she had been taking for restless legs had been the cause. She had never been warned. She had never been monitored. In two decades of prescriptions, a doctor had questioned her behaviour once, when she arrived for an appointment carrying shopping bags.

She is angry. She will live with the consequences for the rest of her life.

And she is still on the drug. Because it is the only thing that works.

To understand what the medication was doing to Sally’s accumulated myelinated condition, it helps to begin with a condition the Myelin Mind has already examined through the same lens: Tourette’s syndrome.

The tic, whether vocal or motor, is a signal that arrives in the nervous system without completing the intentional arc, the chiasmic encounter between incoming signal and the accumulated myelinated condition that would ordinarily contextualise and redirect it. The premonitory urge that precedes a tic is the signal demanding expression. The accumulated myelinated condition cannot meet it with adequate contextual force. The expression breaks through the arc rather than completing it.

Restless legs syndrome is the same biological structure applied to a different motor territory. The leg that must move in the evening, the unbearable urge that prevents sitting, watching, resting, is not a voluntary act and not quite an involuntary one either. It is a chiasm that cannot complete normally. The dopamine agonist works, in both conditions, by restoring enough D2 and D3 receptor signalling in the striatum to give the accumulated condition a stronger foothold in the encounter with the motor signal. The arc can complete. The leg is still.

But the D3 receptor also sits in the limbic reward circuitry, the region that modulates the experience of reward, novelty, and risk. The same drug that restores the motor intentional arc also amplifies the reward signal beyond what the prefrontal accumulated condition can contextualise. The prefrontal white matter that would ordinarily meet the reward signal with proportion, consequence-evaluation, and the weight of accumulated self-knowledge is being bypassed by a pharmacological signal of sufficient intensity to override it.

The shopping chiasm cannot complete adequately either. Sally was not a person with a shopping problem. She was a person whose accumulated myelinated condition was being systematically overwhelmed by a reward signal that the drug had amplified beyond the point where the white matter she had built over a lifetime could be heard. The drumbeat she described, the compulsion that would not stop, is the biology of a chiasm running without adequate context. The drug solved one incomplete arc by producing another.

The neurologist who first linked these drugs to compulsive behaviour described his patients as losing their moral compass. The moral compass is the accumulated myelinated condition: the self, inscribed in white matter, that provides the contextual evaluation the reward signal is supposed to be met with. The drug did not remove Sally’s compass. It jammed the signal the compass runs on.

The legal framework was established in France in 2012, when Didier Jambart sued GlaxoSmithKline over Requip, the same class of drug. Before taking it he had no history of gambling, no history of compulsive sexual behaviour. Within two years he had gambled away his family’s savings, become addicted to anonymous sexual encounters, been assaulted, and attempted suicide eight times. A French court found that the drug had caused the behaviours and the company had failed to warn him adequately of a risk their own clinical data had been generating signals about for years.

Jambart’s case was not isolated. In 2008 a US court awarded $8.2 million to a patient against the makers of Mirapex. In 2015 Pfizer settled confidentially with 172 Australian patients for sums running to millions of dollars. Public Citizen sued the FDA in 2019 to force black box warnings onto six dopamine agonist medications, after waiting two and a half years for the agency to act on a petition filed in 2016. More than thirteen percent of patients on these drugs develop at least one impulse control disorder. Some studies put the figure closer to twenty-five percent.

The Jambart verdict established the central legal finding: the drug caused the behaviour, the manufacturer knew or should have known, the warning was inadequate, and the chain of prior fault ran through the manufacturer’s disclosure rather than the patient’s voluntary act.

Jambart stopped taking Requip. The behaviours stopped. His accumulated myelinated condition, temporarily overwhelmed, reasserted itself when the pharmacological override was removed. The before and after of his case is the before and after of a signal being switched off.

Sally’s case is harder, and the law has not yet caught up with it.

She cannot stop taking the drug. RLS has no other treatment that works for her. The choice she faces every day is not between the person she was and the person she is on the medication. It is between the restless legs that destroyed her sleep for years and the compulsive spending that destroyed her finances and her home. She has reduced her dosage to manage the override, but it is still there, and she battles it with every purchase, asking herself whether this one is compulsive, whether she is doing it again.

This is not recovery. It is permanent negotiation. The accumulated myelinated condition that was overwhelmed by the drug has partially reasserted itself through conscious effort, but it is doing so against an ongoing pharmacological pressure it cannot fully resist. The self is fighting back against a signal it cannot permanently silence because the drug cannot be removed.

The legal question Jambart’s verdict does not answer is this: what is the duty of care when stopping is not an option? When the patient is permanently trapped between the condition the drug treats and the condition the drug causes, and must manage the override consciously for the rest of their life? The pharmaceutical company’s liability does not end when Sally reduces her dose. It extends into the permanent condition the undisclosed risk has created: the £500,000 gone, the house sold, the daily vigilance that she will maintain for as long as she needs the medication.

There is also a dimension the Jambart case did not surface directly. NICE guidelines require that doctors discuss impulse control risks with Parkinson’s patients at review appointments. Parkinson’s patients are predominantly men. There are no equivalent monitoring guidelines for RLS patients. RLS patients are predominantly women. Sally was prescribed the same class of drug, carrying the same documented risk, and received none of the monitoring that would have been required for a male Parkinson’s patient taking the same medication. Her shopping was not flagged as pathological because shopping by women is culturally legible as extravagance. A man losing the same amount at a casino would have triggered different responses from the people around him.

The monitoring gap is not an oversight. It is a systematic failure to extend the same duty of care to a predominantly female patient population taking the same drug for a different indication. Sally is right to name it as a health scandal where women are sidelined. The Myelin Mind would add: it is also a failure of the clinical framework to recognise that the accumulated myelinated condition is equally at risk in both patient groups, regardless of the indication, because the pharmacological override acts on the same receptor in the same reward circuitry in every brain that receives it.

The acts were Sally’s. The override was not. And the override is not over.

Whose Behaviour Is It? Pharmacological Coercion and the Myelinated Self

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