Marijuana refers to the leaves and flowers of the cannabis plant which is smoked. The resin produced by the flowering tops contains about 10-25% of THC and oil based plant extract of cannabis plant called hash oil contains about 25-60% of THC. Smoking is the commonest method of consumption of cannabis.
How Many people smoke Marijuana?
Marijuana is the most commonly used drug in US and much of the world. In US it is estimated that 37% of teens have smoked at least one reefer in their lives. It is estimated that a further 5-10% of these individuals could abuse cannabis on a chronic basis. Cannabis use is widespread in south east and central Asia.
What Are the Short-Term Effects of Marijuana Use?
The immediate effects of marijuana are euphoria, disinhibition, a general feeling of goodness, altered sensory perceptions, inattention, insomnia, loss of memory and poor reflexes. The active ingredient THC crosses the blood brain barrier and stimulates specific receptors in a mid brain structure called nucleus accumbens. This leads to release of dopamine, a central exitogenic neurotransmitter. This activates the pleasure pathway comprising the hippocampus and limbic pathway. With constant use, the individual becomes psychologically addicted to marijuana.
The two physical effects of marijuana use are conjunctival injection and increased heart rate. The increase in heart rate stabilises over ti