chapter  7
Drugs of abuse
ByAnne Lingford-Hughes, Mark Daglish
Pages 20

Chewing tobacco → Snuff → Cigarettes Coca leaves → Coca paste → Cocaine → Crack cocaine Methadone → Morphine → Snorted heroin → Intravenous heroin

■ The pattern of drug use changes with time depending on what is available, the social context and how much it costs.