Doctors now believe that a type of medicine - called dopamine receptor agonists - can cause some patients to become compulsive gamblers, binge shoppers or sex addicts.
It’s thought the drug causes this adverse reaction by over-stimulating the ‘pleasure seeking’ chemistry of the brain. But many people find this hard to believe: how can a drug alter your behaviour against your will? If you do bad things, that’s your choice, and we shouldn't blame a drug. After all, don’t humans have ‘free will’?
And yet, we are all composed of chemistry that controls everything we do. If your body’s chemistry changes, because of say a serious illness, or a profound injury, or the effects of a powerful drug, is it so difficult to believe that your behaviour and personality could consequently change too?