Cannabis and the lung
- Dr Peter Lange, Department of Cardiology and Respiratory Medicine, Hvidovre Hospital, Copenhagen, Denmark;
Cannabis (or marijuana) is not only the most widely used illegal drug in the western world but, after tobacco, also the most commonly smoked substance. In the UK almost 50% of young adults have tried to smoke cannabis at some time.1 Among people aged 16–30 years of age there is a substantial number of frequent users, in some populations in the range of about 5%. The active substance responsible for the psychostimulating effect of cannabis is delta9-tetrahydrocannabinol (THC). However, as with tobacco smoke, cannabis smoke consists of a large mixture of compounds including polycyclic aromatic hydrocarbons, carbon monoxide, cyanide, benzene and many others.
Cannabis is prepared from the hemp plant which—especially in the 19th and the beginning of the 20th century—was grown for industrial purposes in order to produce fibres, but it has gradually been replaced by other coarse-fibre plants. Archaeological findings show that cannabis was used in many ancient cultures in spiritual and religious contexts as a psychostimulating and trance-inducing drug. Later, in the 19th century, it was promoted for its medical properties including pain-relieving, antiemetic and anticonvulsant effects. Yet, after the invention of aspirin and other more effective drugs, the use of …