Associated descriptive features and mental disorders. The associated features of Dysthymic Disorder are similar to those for a Major Depressive Episode. Several studies suggest that the most commonly encountered symptoms in Dysthymic Disorder may be feelings of inadequacy; generalized loss of interest or pleasure; social withdrawal; feelings of guilt or brooding about the past; subjective feelings of irritability or excessive anger; and decreased activity, effectiveness, or productivity. (Appendix B provides an alternative for Criterion B for use in research studies that includes these items.) In individuals with Dysthymic Disorder, vegetative symptoms (e.g., sleep, appetite, weight change, and psychomotor symptoms) appear to be less common than for persons in a Major Depressive Episode. When Dysthymic Disorder without prior Major Depressive Disorder is present, it is a risk factor for developing Major Depressive Disorder (in clinical settings up to 75% of individuals with Dysthymic Disorder will develop Major Depressive Disorder within 5 years). Dysthymic Disorder may be associated with Borderline, Histrionic, Narcissistic, Avoidant, and Dependent Personality Disorders. However, the assessment of features of a Personality Disorder is difficult in such individuals because chronic mood symptoms may contribute to interpersonal problems or be associated with distorted self-perception. Other chronic Axis I disorders (e.g., Substance Dependence) or chronic psychosocial stressors may be associated with Dysthymic Disorder in adults. In children, Dysthymic Disorder may be associated with Attention-Deficit/Hyperactivity Disorder, Conduct Disorder, Anxiety Disorders, Learning Disorders, and Mental Retardation.
Associated laboratory findings. About 25%-50% of adults with Dysthymic Disorder have some of the same polysomnographic features that are found in some individuals with Major Depressive Disorder (e.g., reduced rapid eye movement [REM] latency, increased REM density, reduced slow-wave sleep, impaired sleep continuity). Those individuals with polysomnographic abnormalities more often have a positive family history for Major Depressive Disorder (and may respond better to antidepressant medications) than those with Dysthymic Disorder without such findings. Whether polysomnographic abnormalities are also found in those with “pure” Dysthymic Disorder (i.e., those with no prior history of Major Depressive Episodes) is not clear. Dexamethasone nonsuppression in Dysthymic Disorder is not common, unless criteria are also met for a Major Depressive Episode.