Learning has also been proposed as an independent facet of reward that may be impaired in conditions associated with anhedonia, but empirical evidence dissociating learning from either "liking" or "wanting" is lacking.Anhedonia has also been used to refer to "affective blunting", "restricted range of affect", "emotional numbing", and "flat affect", particularly in the context of post-traumatic stress disorders. In PTSD patients, scales measuring these symptoms correlate strongly with scales that measure more traditional aspects of anhedonia, supporting this association. Causes
Studies in clinical populations, healthy populations, and animal models have implicated a number of neurobiological substrates in anhedonia. Regions implicated in anhedonia include the prefrontal cortex as a whole, particularly the orbitofrontal cortex (OFC), the striatum, amygdala, anterior cingulate cortex (ACC), hypothalamus, and ventral tegmental area (VTA). Neuroimaging studies in humans have reported that deficits in consummatory aspects of reward are associated with abnormalities in the ventral striatum and medial prefrontal cortex, while deficits in anticipatory aspects of reward are related to abnormalities in hippocampal, dorsal ACC and prefrontal regions. These abnormalities are generally consistent with animal models, except for inconsistent findings with regard to the OFC. This inconsistency may be related to the difficulty in imaging the OFC due to its anatomical location, or the small number of studies performed on anhedonia; a number of studies have reported reduced activity in the OFC in schizophrenia and major depression, as well as a direct relationship between reduced activity and anhedonia.
PTSD is also associated with blunted affect, which may be due to the high comorbidity with depression. Parkinsons disease
Anhedonia occurs frequently in Parkinsons disease, with rates between 7%–45% being reported. Whether or not anhedonia is related to the high rates of depression in Parkinsons disease is unknown. Bipolar depression
Anhedonia is also reported to appear in people with bipolar depression. Attention deficit hyperactivity disorder
Anhedonia may be associated with ADHD. Impairments of dopaminergic and serotonergic function in the brain of those with ADHD result in dysregulation of reward processing which can lead to anhedonia. Sexual anhedonia
Sexual anhedonia in males is also known as ejaculatory anhedonia. This condition means that the man will ejaculate with no accompanying sense of pleasure.The condition is most frequently found in males, but women can experience 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 of SSRI antidepressants or having used SSRI antidepressants in the past. Use (or previous use) of antidopaminergic neuroleptics (anti-psychotics)
Fatigue
Physical illnessIt is very uncommon that a neurological examination and blood tests can determine the cause of a specific case of sexual anhedonia. Patients may be prescribed sustained-release bupropion to aid in treatment, which has been shown to relieve sexual dysfunction even in patients without depression. Social anhedonia
Definition
Social anhedonia is defined as a disinterest in social contact and a lack of pleasure in social situations, and is characterized by social withdrawal.