Opiate addiction
Raw opium, and all the drugs derived from it, or manufactured to emulate it, are highly addictive. Medical professionals do prescribe Opiods, when strong pain killers are required, but they do so cautiously, due to its highly addictive nature. Patients with a terminal disease are prescribed opiates, because they are expected to die soon, long term addiction is not considered a problem.
Opiates can induce a strong feeling of euphoria, called a "rush", or a "high", which is what triggers users to seek out an additional dose. However, this effect fades, requiring addicts to seek out higher and higher doses. Many addicts work as prostitutes, or engage in criminal activity, to find the funds to acquire more drugs.
Drug users sniff, smoke, or inject opiates. Injection produces the most intense high, and is the most dangerous way to use drugs, as needy addicts routinely neglect the precautions to make sure their needles are clean, and can infect themselves with the diseases earlier users of the needle had. AIDS and hepatitis are among the disease spread by intravenous drug use.