DYSTHYMIA. — Abnormal variation in the affective life of psychopathic individuals oscillating between manic exaltation (v. MANIA) and melancholic depression (v. MELANCHOLIA) not motivated by external circumstances (endogenous causes). Dysthymias constitute, in particular, the building elements of manic-depressive psychosis. They can, on the other hand, present dysthymic pictures in the course of the most varied nervous and mental illnesses in which mood variations represent one of the symptoms or transient, non-specific episodes of the disease.
Thus in epilepsy, with a tendency toward irritability, gloomy, sad, pessimistic forms, lasting anxiety, assuming a suspicious and violent demeanor; in progressive paralytic dementia, with manic exaltation, euphoria, psychomotor excitability; in senile dementia and in the climacteric age (v. CLIMATERICA, ETÀ), with a tendency toward melancholic depressive forms; in alcoholism (v. CHRONIC); in early dementia or schizophrenia (v.); in hysteria. In some dysthymic forms, doubt may remain as to how much belongs to external causes of family and social environment or to constitutional endogenous causes; often we discern in individuals a nearly serial variability between the cycloid temperament (v. INDULTO) with easy, poorly motivated instability of mood and the true dysthymic forms, to be classified among morbid pathological pictures.