Can marijuana abuse cause or alleviavate depression?

Not really: There is no evidence that mj can lead to depression. Mj can sometimes diminish the symptoms of depression, but it is not a solution for treating the depression itself. Therapy and/or medication is what should be utilized to treat depression.

Yes: Marijuana use temporarily relieves depression/anxiety and withdrawal exacerbates this. Withdrawal can take weeks to resolve. Several years ago, a study comparing daily users to a normal population found a lower incidence of depression in marijuana users suggesting a treatment of depression by marijuana. However, too many side effects and varying serum levels make it a poor choice for rx.