The effect of any drug on an individual is the result of three interacting factors:
- the drug itself
- the individual user
- the environment in which drug use occurs.
The effect that a drug has on a person is determined by many factors. The primary factors that influence drug effect are the type of drug and the quantity used.
Other factors include:
- the time taken to consume the drug (10 minutes vs 10 hours)
- the user's tolerance (e.g. regular cannabis smoker vs na´ve smoker)
- the user's gender, size and amount of muscle
- other psycho-active drugs in the person's bloodstream (poly-drug use)
- the mood or attitude of the user (e.g. angry vs calm, confident vs fearful)
- the user's expectation of the drug effect (e.g. expecting a powerful drug effect vs expecting a modest drug effect)
- the setting or environment in which the drug is consumed (e.g. wild party vs quiet night at home).