Frequent cigarette smoking (which is common on British television), drinking (the legal age is lower in Britain), and drug use -- including prescription pills and marijuana (referred to as "spliff" and "skunk").
Season 1 - Drugs are a frequent topic of discussion and are shown being used and abused often in very graphic detail (cocaine, heroin, opioids, marijuana and more).
Season 2 - Hard drug use like cocaine is shown in detail.
Season 3 - Contains frequent usage of extremely hard drugs (shown explicitly).
Season 4 has a ridiculous and quite frankly over the top amount of drug use, especially in episode 7.
Series 5 has the usual wild amount of drugs such as cocaine, pills and molly.
The drug use gets more explicit as the show goes on.
Strong drug use and teen partying in most of episodes.
Various drugs are portrayed throughout series, including alcohol, tobacco, cannabis, mdma, cocaine, pharmaceuticals, psychedelics, and other drugs.
People occasionaly snorting cocaine/mdma, taking various pills.
Lots of weed/cigarettes are smoked throughout every episode.
In season 1, there is an episode where a character injects pure heroin into themself.