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By Dr Devan
Gambling (and other impulse-control problems) are recognised side effects of several Parkinson’s disease (PD) medications, especially those that act on dopamine receptors.
Here’s a clear, detailed explanation 1. The Core Problem: Dopamine Overstimulation
Parkinson’s disease itself is caused by dopamine deficiency in the brain (particularly in the substantia nigra).
Treatment, therefore, involves replacing or mimicking dopamine — but too much stimulation of certain dopamine pathways (especially the mesolimbic “reward” system) can lead to addictive or impulsive behaviours.
2. Drugs Most Commonly Implicated
Drug class Examples Risk level for gambling/impulse control disorders
Dopamine agonists Pramipexole (Mirapex), Ropinirole (Requip), Rotigotine (Neupro), Apomorphine 🚨 Highest risk
Levodopa (Sinemet, Madopar) Levodopa/carbidopa, Levodopa/benserazide Moderate risk
MAO-B inhibitors Rasagiline, Selegiline Low risk
COMT inhibitors Entacapone, Tolcapone Low risk
The dopamine agonists are the main culprits — they directly stimulate D3 receptors in the limbic system (the brain’s reward and pleasure center), which drives risk-taking, reward-seeking, and compulsive urges.
3. Typical Impulse-Control Behaviours Seen
These can appear weeks to months after starting or increasing the dose:
Pathological gambling – uncontrollable urge to gamble despite losses.
Compulsive spending – shopping sprees or giving away money.
Binge eating – eating far beyond satiety.
Hypersexuality – increased libido, risky sexual behavior.
Excessive internet or video game use.
Punding – repetitive, purposeless activities (e.g. sorting, cleaning, assembling).
These are all part of Impulse Control Disorder (ICD) spectrum.
4. How Common Is It?
Occurs in about 10–20% of patients on dopamine agonists.
Gambling specifically: 2–8% of patients.
Risk increases with:
Higher dopamine agonist doses
Younger age (<65 years), Male gender
History of addiction or novelty-seeking personality
Concurrent antidepressant or stimulant use
5. Biological Mechanism
The mesolimbic dopaminergic pathway — from the ventral tegmental area (VTA) to the nucleus accumbens — governs reward, motivation, and pleasure.
Dopamine agonists, particularly D3-preferring drugs like pramipexole, overactivate this pathway → excessive “reward seeking” → pathological gambling or compulsive behaviour.
6. Warning Signs for Families & Caregivers
Sudden preoccupation with casinos, online betting, or lottery tickets.
Secretive spending, new debts, or unexplained withdrawals.
Staying up late to gamble or use devices.
Mood swings are tied to wins or losses.
Loss of interest in usual hobbies or family interactions.
7. Management Strategies
Recognize early — openly discuss with patient and family.
Adjust or discontinue dopamine agonist under neurologist supervision.
Symptoms often improve within weeks to months after stopping the drug.
Switch to Levodopa-based regimen (lower impulse risk).
Add behavioral therapy or counselling (CBT).
In severe cases:
Consider naltrexone or SSRIs for impulse control.
Deep brain stimulation (DBS) may help selected cases.
8. Important Note
These behaviors are drug-induced, not moral failings.
When the medication is reduced or stopped, most patients return to normal behaviour.
Therefore, routine screening for gambling or hypersexuality is recommended in every Parkinson’s patient on dopamine agonists.
Summary Table
Aspect Detail
Cause Dopamine agonists overstimulate reward circuits
Common drugs Pramipexole, Ropinirole, Rotigotine
Main behaviours: Gambling, hypersexuality, binge eating, compulsive buying
Reversibility: Usually reversible after dose reduction or drug change
Management: Stop agonist, switch to levodopa, counselling, and close family supervision.
*Dr Devan is a Mangaluru-based ENT specialist and author
Hindusthan Samachar / Manohar Yadavatti