The condition in which the need of oneself to perform a certain activity to satisfy a desire is great enough to cause the person to continue the behaviour.

An addiction is not necessarily harmful to one's health, nor is it necessarily a negative situation to be in. This is a key point that many drug warriors fail to recognise. The harmfulness of an addiction is determined not by its presense nor by the severity of it, but by the dangers of the behaviour to which one is addicted. Drug warriors sometimes state the possibility of addiction alone as a reason to abstain from drug use, when in reality one should be concerned with the direct firsthand dangers of taking the drug in question, in light of the fact that addiction could occur.

The severity of an addiction is determined by the strength of the desire to perform the activity. For instance, a user addicted to crack, running low on money, may eventually favour paying for a hit on the crack pipe over purchasing food, leading to starvation. Other addictions, such as to Cannabis, are never strong enough to force the user to make sacrifices to their health, other than those caused by the drug itself, which are minimal.

Addictions are not limited to drug use, however. Common addictions are to:

Addictions can become degrading to one's overall well-being for several reasons. It may become difficult for one to finance their habit. The crackhead example was illustrated earlier. Also, addictions can be time-consuming. This can make experiencing pleasure through other means more difficult. In addition, addictions tend to piss people off, especially in respect to drug use. Today's society has little understanding of drugs, drug users, and drug culture. Finally, the activity to which one is addicted can be harmful directly to the person's health.