A tolerance for a drug develops when it is necessary for a person to increase their doses in order to obtain the initial effect of a lower dose. There may be psychological or physical dependencies. Some of the discomforting symptoms are irritability, restlessness, sleep disturbance, tremor, salivation, sweating, nausea, vomiting, diarrhea, decreased appetite, and weight loss. Mild physical dependencies occur with the regular use of very high doses of marijuana. When a person stops taking the drugs they experience some of the symptoms listed above.
Psychological dependencies occur as often as physical dependencies.