Assessment Beyond reliance on risk factors for screening, the parameters discussed the roles of toxicology testing and medical and physiological issues in assessing substance use disorders. Other possible indicators are being a victim or perpetrator of violent acts, engaging in unprotected and unsafe sexual activity with subsequent pregnancy or sexually transmitted disease, and having human immunodeficiency virus infection, which is a risk factor among some intravenous drug and crack cocaine abusers. Toxicological methods, however, can provide a check of adolescent truthfulness. A positive drug screen does not prove substance abuse or dependence, but does indicate substance use. The effectiveness of drug screens may be limited by the brief presence in the body of many substances of abuse and their metabolites.
Stimulants are detectable in the urine for up to one or two days.
Cannabis, which is lipid soluble, may be detected for one month or more when use has been chronic. In many ways adolescents who use and abuse substances differ from adults. What we would call physiologic dependence is much less common among adolescents. Adolescent use tends to be more sporadic. The use of multiple substances is more characteristic of adolescents with difficulties than it is with adults with difficulties.