In general, an illicit drug overdose can be defined as a drug dose that is large enough to be toxic. It can be fatal or nonfatal, depending on the amount of drug or combinations of drugs consumed. Medical attention is promptly needed for anyone who has accidentally or deliberately taken an overdose.
This notwithstanding, studies on illicit drug overdoses often utilize their own definition of an overdose in order to fulfill their research purposes. For example, a study in which injection drug users were interviewed to characterize overdose events defined overdose as “a situation where, after using, you or another person passed out and could not wake up. The lips of the person who overdosed might have turned blue and their breathing was very slow or stopped.”