The National Collegiate Athletic Association has policies in place for testing college athletics for both performance enhancing drugs as well as street drugs. There are many policies that are ambiguous in nature in these policies.
One thing that sticks out in my mind is the fact that dietary supplements could involve a banned substance within them. The problem is, the label will not always tell you these drugs that are banned, and an athlete could test positive, and lose one full year of eligibility. Street drugs, if have a positive result, could result in 50% in loss of season which could be the first or second half.
To me, the testing for marijuana and other street drugs is an outdated concept since it is legal in four states and medically legal in many other states. The tests are not all that random with each athlete knowing from their coach ahead of time that they may be tested in the future. They are very rare. The other time that athletes are tested are at championship events.
Drug testing can slow the use of drug use on college campuses among athletes but not to the full effect. To rid NCAA athletes of using drugs they would randomly select all athletes at different times. This is a large sum of money for the drug tests, and with each school having different rules, not every time would an athlete be out for even taking the drugs.
An article by Orlando Sentinel outlines that the NCAA is debating on whether to continue with the testing of drugs that are not performance enhancing or if they will continue. This issue has been talked about since 2012 since the onsets of legalization of marijuana in states. Financially and ethically this no longer makes sense to test for street drugs besides the fact that the NCAA wants to protect athletes from the harmful side-affects of drugs.