The mild depression associated with dysthymia often leads to a lack of interest in activities that the person used to enjoy. He may also become withdrawn and take a critical look at life. In addition, the constant gloom can result in changes in eating and sleeping patterns. It may become difficult for him to focus, and feelings of despair may become common [source: PubMed Health].
Dysthymia is also characterized by snowball effects. For example, because a person with dysthymia becomes pessimistic, he views unpleasant-but-natural occurrences in life as more traumatic than they really are -- which leads to an even deeper depression. Likewise, because he isn't fun to be around, he becomes more isolated, and that can create a more severe problem [source: Harvard Health Publications].
Suspected causes of dysthymia range from biochemical issues to genetics to environmental factors [sources: Mayo Clinic]. Chemicals in the brain that influence mood may be imbalanced, a person's family history is likely to indicate common instances of depression, and events such as childhood or adult trauma can precipitate dysthymia. Research indicates that approximately 75 percent of those with the condition also have another mental or physical issue, including drug and alcohol dependence [source: Harvard Health Publications]. And women appear to be more at risk than men.