In psychology and psychiatry, anhedonia (< Greek ἀν- an-, "without" + ἡδονή hēdonē, "pleasure") is an inability to experience pleasurable emotions from normally pleasurable life events such as eating, exercise, social interaction or sexual activities. This is considered as one of the negative symptoms of Schizophrenia where patients describe themselves as feeling emotionally empty.
Changing of mood are the most likely to observe in psychiatric disorder. They are the significant symptoms of depression but they can be easily seen in other psychiatric disorders during physical illness. In healthy people, changing mood is also prominent when encountering stressful events 
Researchers theorize that anhedonia may result from the breakdown in the brain's reward system, involving dopamine pathways. Two 2005 studies by Paul Keedwell MD of King's College found that certain sections of the brain in depressed subjects had to work harder to process happy thoughts.
Anhedonia is often experienced by drug addicts following withdrawal; in particular, stimulants like cocaine and amphetamines cause anhedonia and depression by depleting dopamine and other important neurotransmitters. Very long-term addicts are sometimes said to suffer a permanent physical breakdown of their pleasure pathways, leading to anhedonia on a permanent or semi-permanent basis due to the extended overworking of the neural pleasure pathways during active addiction, particularly as regards to cocaine and methamphetamine. In this circumstance, activities still may be pleasurable, but can never be as pleasurable to people who have experienced the comparatively extreme pleasure of the drug experience. The result is apathy towards healthy routines by the addict.
Anhedonia may also be an effect of prolonged fatigue.
Significance in depression
As a clinical symptom in depression, anhedonia rates highly in making a diagnosis of this disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM) describes a "lack of interest or pleasure" but these can be hard to tell apart given that people become less interested in things which do not give them pleasure. The DSM criterion of weight loss is probably related to it and many depressed people with this symptom describe a lack of enjoyment of food. People suffering from anhedonia in association with depression generally feel good in the morning and unhappy in the evenings and can portray any of the non-psychotic symptoms and signs of depression. 
The condition is most frequently found in males, but women can suffer from lack of pleasure when the body goes through the orgasm process as well.
Sexual anhedonia may be caused by:
- Hyperprolactinaemia
- Hypoactive sexual desire disorder (HSDD), also called inhibited sexual desire
- Low levels of the hormone testosterone
- Spinal cord injury
- Multiple Sclerosis
- Use (or previous use) of SSRI antidepressants
- Physical illness
It is very uncommon that a neurological examination and blood tests can determine the cause of a specific case of sexual anhedonia.
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- Hales R., Yudofsky S., Talbott J. 1999. Textbook of Psychiatry 3rd ed. Washington DC: The American Psychiatric Press.
- Gelder, M., Mayou, R. and Geddes, J. 2005. Psychiatry. 3rd ed. New York: Oxford. pp 2, 99.
- "No Pleasure, No Reward -- Plenty of Depression" by John McManamy; URL accessed 2009-02-17
- "Neural systems underlying affective disorders" by Simon Surguladze, et al., Advances in Psychiatric Treatment (2003) 9: 446-455; URL accessed 2008-02-08
- David A. Tomb (1 August 2007). Psychiatry. Lippincott Williams & Wilkins. p. 44. ISBN 9780781774529. http://books.google.com/books?id=lt0-i8xLINoC. Retrieved 18 December 2010.
- "Persistent Sexual Dysfunction after Discontinuation of Selective Serotonin Reuptake Inhibitors" By Csoka et al., Journal of Sexual Medicine 5 (1) , 227–233; URL accessed 2008-02-28
- Crenshaw TL, Goldberg JP, Stern WC (1987). "Pharmacologic modification of psychosexual dysfunction". J Sex Marital Ther 13 (4): 239–52. PMID 3121861.
- Anhedonia - Bipolar Disorder Symptoms
- No Pleasure, No Reward
- Forum: "Ejaculation without orgasm" forum (hisandherhealth.com) 
- Forum: "Ejaculatoryanhedonia.com" 
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