Unformatted text preview: • You have to learn how to use marijuana
– Novice users often report no effect on first use
– Second or third time, sensitization may occur
“reverse tolerance”, may be due to learning ‘how’
to get high
– Users learn to be more aware of the effects of the
• Tolerance is dose dependent.
• At doses used by most Americans (1 joint/day),
little tolerance is observed
• No evidence for metabolic tolerance
• Tolerance due primarily to desensitization and /
or downregulation of cannabinoid receptors
or Tolerance Desensitization and downregulation of cannabinoid
receptors produced by chronic THC exposure. Dependence
Risk of dependence is related to drug use
patterns. People who progress to daily use
have a 50% probability of become dependent.
But most users do not become dependent.
Dependence is manifested as a difficulty in
stopping one’s use, a craving for marijuana,
and unpleasant withdrawal symptoms.
Withdrawal symptoms include irritability,
anxiety, depression, sleep disturbance,
aggressiveness, decreased appetite.
aggressiveness, Dependence – withdrawal symptoms
Dependence Psychological Dependence
• There is evidence that certain people can become
psychologically addicted to cannabis
• Not an issue for the majority of users
• Most users do not exhibit signs of addiction such as:
a constant craving, high frequency use, the build-up
of tolerance, or possible withdrawal symptoms
• However, a very small fraction of users do become
dependent on daily use, and continue to use despite
negative consequences (drug abuse).
negative Adverse Long Term Effects
- Means that chronic marijuana smoking will lead to the use
of other more harmful drugs
- Probably related to individual bio-psychosocial factors as
opposed to anything specific to THC’s effects on the brain.
- Means that chronic marijuana smoking is responsible for a
generalized sense of apathy and indifference to long term
plans and goals
- Chronic pulmonary disease; decreased production of sex
hormones; poor outcomes in pregnancy; overdose?
hormones; Spice – synthetic cannabinoids
• Dried, shredded plant
material with chemical
• “Not for human
• Unknown pharmacology –
stronger / weaker / different
• High heart-rate, vomiting,
confusion Next time
Lecture 17: Alcohol...
View Full Document
- Fall '08
- Cannabis, thc, cannabinoid receptors