Tolerance to many depressants can develop rapidly, with larger doses needed to achieve the same effect. The user, trying to reach the same high, may raise the dose to a level that results in coma or death by overdose.

Long-term use of depressants can produce depression, chronic fatigue, breathing difficulties, sexual problems and sleep problems. As a dependency on the drug increases, cravings, anxiety or panic are common if the user is unable to get more.

Withdrawal symptoms include insomnia, weakness and nausea. For continual and high-dose users, agitation, high body temperature, delirium, hallucinations and convulsions can occur. Unlike withdrawal from most drugs, withdrawal from depressants can be life-threatening.

These drugs can also increase the risk of high blood sugar, diabetes, and weight gain (instances of up to 100 pounds have been reported).

In a study conducted by USA Today, based on Food and Drug Administration data over a four-year period, antipsychotics (a type of depressant) were the prime suspects in forty-five deaths caused by heart problems, choking, liver failure and suicide.

“I have overdosed twice off of prescription pills (Zyprexa) and had a close friend die of the same drug....There is no worse feeling than knowing that your friend is dead because you gave him pills you knew relatively little about.”