Anhedonia

Anhedonia is a condition in which someone cannot experience pleasure or positive emotions. Anhedonia is often a symptom of depression and can also occur with other diseases, such as thyroid disease, multiple sclerosis, Parkinson's disease, migraine, brain tumors, and epilepsy. Anhedonia can be a side effect of some medications, particularly those for treating high blood pressure. Some researchers also believe that crack users experience severe anhedonia, following a binge. In an attempt to relieve this anhedonia, they are driven to use more crack.

Crack.