When "Sarah" climbed up into the attic of her father's house - she was completely unprepared for what she would find.
Her father, "James", was a modest man who worked most of his life for the same company. He retired about 20 years ago when he was diagnosed with Parkinson's.
He had managed the tremors and balance difficulties caused by the disorder by taking a prescription drug called Ropinirole.
But during the Covid-19 pandemic, Sarah had grown increasingly alarmed about her father's secrecy and wanted to see what he had been spending his time doing.
In the loft, she discovered reams of handwritten notes and a dozen recording devices he had been using to bug his own home.
In writing and on tape he had documented innocent sounds his wife had made as she moved around the house, and while she slept, to try to prove she was having an affair. He had also catalogued details of numerous chat lines and porn websites he had been obsessively using.
It was only when Sarah took him to see his specialist nurse five years ago that she learned the medication her father was on could have such extreme side effects.
James lives in a specialist care home and Sarah says she has been told that he has sexually assaulted staff there.
"This medication has torn my family apart," says Sarah - whose name we have changed along with her father's.
James's case is one of 50 the BBC has now been contacted about, the majority concerning men being treated for movement disorders whose behaviour changed dramatically after being prescribed medication from a specific family of drugs.
The risk of impulsive behaviour side effects of dopamine agonist medication have long been known - but the BBC has discovered that doctors are still not warning all patients who have been prescribed the drugs for a variety of conditions.
In March we revealed how British drug company GSK had found a link between Ropinirole and what it called "deviant" sexual behaviour - including paedophilia - in 2003.
GSK told the BBC it had shared these findings with health authorities, included this safety advice in medication leaflets, and conducted extensive trials for the drug which has been prescribed for 17 million treatments.
But warnings about such behaviour were not included in leaflets until 2007 - and, even now, only specify "altered" sexual interest and "excessive" or "increased" libido as risks.
Safety advice about the medication's "toxic" side-effects needs to be strengthened immediately because their impact can be "devastating", according to the acting chair of the Health Select Committee, Labour MP Paulette Hamilton.
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Source: BBC News, 26 July 2025