Far more harm is caused by the criminal prohibition of marijuana than by the use of marijuana itself.

Convicted marijuana offenders are denied federal financial student aid, welfare and food stamps, and may be removed from public housing. Other non-drug violations do not carry such penalties. In many states, convicted marijuana offenders are automatically stripped of their driving privileges, even if the offense is not driving related.
REFERENCE: Section 483, Subsection F of the Higher Education Act of 1998; Amendment 4935 to the Personal Responsibility and Work Opportunity Reconciliation Act of 1996; U.S. Bureau of Justice Statistics. 1992. Drugs, Crime, and the Justice System. U.S. Department of Justice: Washington DC; NORML's State Guide to Marijuana Penalties.