The effects of opioids are the same, whether they are taken as prescribed or recreationally. Recreational users, however, are 19 times more likely to start using heroin.

So how do opioids work? There are receptors in your brain that produce noradrenaline, a chemical that helps keep you awake and alert. Opioids block this receptor, so your brain overcompensates by producing even more. This overcompensation leads to you feeling anxious and jittery when you stop taking opioids. Opioid addiction can begin within a few days of use.