Anhedonia
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People with Anhedonia are unable to feel pleasure from such normally enjoyable activities as eating, playing sports, and talking with friends. The term anhedonia means “without pleasure” in Greek. |
Although anhedonia was largely ignored as a symptom of depressionOpens in new window for a long time, today it is recognized as one of the most important primary symptoms of major depressive disorder. The symptoms of anhedonia are also found in other mood and schizophrenic disordersOpens in new window and are sometimes associated with long-term use of particular drugs.
People with anhedonia exhibit unusually flat mood. They also have difficulty in reacting properly to emotional events. A severely depressed mother of a newborn baby, for instance, might experience no pleasure from holding her baby. This loss of pleasure sometimes prevents people from initiating meaningful activities. The lack of positive feelings associated with accomplishing tasks further lessens people’s willingness to seek out pleasurable experiences.
From the point of view of neuroscienceOpens in new window, researchers have proposed that anhedonia occurs with the breakdown of the brain’s reward system called the reward pathwayOpens in new window.
In a classic study, James OldsOpens in new window (1955) identified neurons in the brain that appear to serve as a reward pathway. He demonstrated that animals would learn a number of different responses to get electronic stimulations of these neurons.
Additional evidence of a physiological component of anhedonia are the withdrawal symptoms from drugs like cocaine and amphetamineOpens in new window; withdrawal from these drugs causes depressionOpens in new window and anhedonia by depleting neurotransmitters (chemical messengers in the brain) like dopamine. It appears that some people who are addicted to these drugs for a long time begin to show symptoms of anhedonia. It is possible that this is due to a permanent breakdown of their pleasure pathways in the brain.
Anhedonia also helps distinguish depression from other disorders, especially anxiety disordersOpens in new window. Despite that depressionOpens in new window is accompanied by the common negative emotions of sadnessOpens in new window and fearOpens in new window, depression is different from other disorders in that it has combined symptoms of the diminished capacity to experience pleasure and (usually) the high levels of negative emotions.
A person with major depressive disorder might feel that he is miserable and helpless. At the same time, he might have lost interest in all his favorite activities.
Nevertheless, as mentioned earlier, anhedonia is not restricted to depressed people. People suffering from schizophrenia and personality disorders related to schizophrenia commonly experience anhedonia. In those cases of schizophreniaOpens in new window in which anhedonia is present, there often is the existence of other negative symptoms (symptoms denoting a lack of something) like a reduction in speech and feelings of apathy.
See also:
- Haslam, N., & Rothschild, L. (1990). Pleasure. In D. Levinson, J.J. Ponzetti Jr., & P.F. Jorgensen (Eds.), Encyclopedia of human emotions (2nd ed., pp. 515 – 522). New York: Macmillan Reference USA.
- Olds, J. (1955). “Reward” from brain stimulation in the rat. Science, 122, 878.
- Vacca, G., Ahn, S., & Philips, A.G. (2007). Effects of short-term abstinence from escalating doses of D-amphetamine on drug and sucrose-evoked dopamine efflux in the rat nucleus accumbens. Neuropsychopharmacology, 32, 932 – 939.
