As a counselor for both in class and online drug classes my students and I often discuss the addictive nature of the various drugs. It may surprise you, or not, that a majority of the students taking my class have had a legal problem with respect to marijuana use.
Almost unanimously my students do not believe marijuana to be physically addictive. The addictive potential of a drug varies from substance to substance, and from individual to individual. Dose, frequency, pharmacokinetics of a particular substance, route of administration, and time are critical factors for developing a drug addiction.
An article in The Lancet compared the harm and addiction of 20 drugs, using a scale from 0 to 3 for physical addiction, psychological addiction, and pleasure to create a mean score for addiction.
According to this study, cannabis is not very physically addictive scoring a 0.8 (with three being the most extremely addictive substance). Cannabis was only slightly more physically addictive than Ecstasy (0.7) and LSD (0.3).
However, the study also showed the marijuana can be psychologically addictive with a score of 1.7. In the study this ranked closest to amphetamines (1.9) and alcohol (1.9) in terms of psychologically addictiveness.
Again, despite the fact that it is not very physically addicting, part of the fact being that it stays in your system for up to 30 days, cannabis is not a healthy choice. The American Medical Association does not recommended the use of cannabis for a single ailment.