Early in 2025, BBC Investigations Correspondent Noel Titheradge published his first story about a category of prescription drug with unusual side effects.

People who take dopamine agonist drugs for conditions like Parkinson’s disease or Restless Legs Syndrome often report impulse control disorders - problems with gambling, compulsive eating or shopping, or hypersexuality.

He wasn’t expecting the response. After that first article was published more than 200 people got in touch - that’s me, they said, that’s my partner, that’s my dad.

So Noel started digging.

Details of organisations offering help and support with some of the issues raised are available at bbc.co.uk/actionline.

If you have any concerns about medication you’re taking, speak to your doctor.

Impulse control disorders are a common side effect of dopamine agonist drugs - it’s generally accepted that they will affect around 1 in 6 people taking these drugs for Parkinson’s.

So why are these side effects so hard to talk about? How can people get past their guilt and shame to access the support they need?

And if subtle changes in the activity of chemicals in our brain can cause us to behave so differently - what is personality?

Details of organisations offering help and support with some of the issues raised are available at bbc.co.uk/actionline.

If you have any concerns about medication you’re taking, speak to your doctor.

Presenter: Noel Titheradge Producer: Lucy Burns Editor: Matt Willis A BBC News Long Form Audio production

Respected local solicitor Andrew is sent to prison - but the devastating impact of the side effects of his Parkinson’s medication continues.

BBC Investigations Correspondent Noel Titheradge has been contacted by more than 200 people about their experience of behavioural side effects of dopamine agonist drugs.

So who’s taking responsibility? We hear from pharmaceutical companies, regulators and doctors. There have been significant developments in the way these drugs are used - but what effect have they had?

Details of organisations offering help and support with some of the issues raised are available at bbc.co.uk/actionline.

If you have any concerns about medication you’re taking, speak to your doctor.

Presenter: Noel Titheradge Producer: Lucy Burns Editor: Matt Willis A BBC News Long Form Audio production