Dysthymia is a mood disorder, a mild degree of chronic depression, in which symptoms typically last about a year, in the case of children and adolescents, and at least two years in adults. Sometimes the symptoms are less intense than those of common depression. Currently, the exact cause of dysthymia is unknown, although it is attributed to an alteration of a particular type of neurotransmitter called serotonin, responsible for managing emotions and value judegments. Another possible origin is stressful situations and factors linked to the personality of the person. The two main treatments for dysthymia are drugs and psychotherapy. The latter case may be particularly advisable for people with difficulty making decisions or self-destructive behavioural patterns.