Substance dependence -- three or more of the following in a 12-month period:
- Tolerance
- Withdrawal
- Consuming larger amounts
- Unsuccessful efforts to cut down
- Excessive time spent to obtain the substance in question
- Decreased interest in activities as a result of drug use
- Use despite physical/psychological problems caused by use
Substance abuse -- one of the following in a 12-month period:
- Failure to fulfill a major obligation
- Recurrent use in hazardous situations
- Substance-related legal problems
- Use despite interference in social or interpersonal function