McPartlin has checked into rehab for addiction to the opioid prescription painkiller Tramadol, as well as alcohol abuse issues. Depression, along with chronic pain following a knee operation, left him hooked on the medication which was prescribed to him by his doctor.

Like anyone else, McPartlin would have presumed that the drugs he was prescribed were perfectly safe. But Tramadol is an opioid, and opioids are notorious for their addictive nature. Opioid pain medication is processed in the body in much the same way as heroin, which is derived from the dried milk of the opium poppy.

There are many different types of painkillers in this particular group, ranging in strength from over-the-counter medications like codeine, right up to extremely strong drugs which can only be prescribed by a doctor. But all work in essentially the same way, by depressing the nervous system.