1. Warning Signs

2. Wonder drugs


3. Dopamine Hits


4. Big Pharma, Big Secret


5. Restless


6. Chasing Losses


16 February 2026


When Freddie's father Bill is diagnosed with Parkinson's, his medication offers him a brand-new lease of life. He begins ticking things off his senior citizen bucket list - travelling, sky diving, golf.


But then Freddie notices that his previously sensible dad has actually begun behaving unusually.


BBC Investigations correspondent Noel Titheradge has spent more than a year speaking to people whose behaviour altered significantly after taking a classification of prescription drugs called dopamine agonists.


These drugs enhance dopamine activity in the brain - they were recommended more than 1.5 million times in the UK in 2015 to deal with Parkinson's disease and other motion conditions.


But they have well recognized side effects - around 1 in 6 individuals who take them develop impulse control conditions, which can include hypersexuality, binge eating, compulsive betting and shopping.


If these negative effects have been learnt about for years, why weren't some patients and their warned or kept an eye on?