The active ingredient in cannabis, tetrahydrocannabinol (THC), is fat soluble and may stay in body stores for as long as 6-8 weeks following ingestion. There is evidence to suggest THC accumulates in body stores and is related to acute and chronic psychiatric reactions. Studies addressing the long term effects of heavy cannabis use on the brain have been shown to be related to deficits of focused attention, that is the ability to screen out irrelevant information.

Physical Effects

• Increased risk of respiratory disorders and lung cancer associated with smoking
• Interference with sexual drive and hormone production, including irregularity of menstrual cycle, reduced sperm count and decreased libido

Cognitive and Psychological Effects

• Psychosis (usually reversible with cessation of use)
• Amotivational syndrome (personality and mood changes)
• Impaired attention and concentration
• Impaired short term memory and learning ability