Define addiction. Give the physiological effects of : (a) Cocaine (b) Cannabinoids

Answer:

Addiction is a physical and psychological dependence on certain substances (drugs, alcohol, tobacco) such that the person compulsively uses them in spite of harmful effects and suffers withdrawal symptoms when they are stopped.

(a) Cocaine (from Erythroxylum coca): it interferes with the transport of the neurotransmitter dopamine and is a powerful stimulant of the central nervous system, producing euphoria and increased energy. Excess use causes hallucinations, increased heart rate and blood pressure, and can damage the heart and nervous system.

(b) Cannabinoids (from Cannabis sativa: marijuana, hashish, charas, ganja): they act on cannabinoid receptors in the brain and mainly affect the cardiovascular system; they cause altered perception, euphoria, impaired memory and coordination, and increased heart rate.