Dysthymic disorder is defined by the presence of chronic de-pressive
symptoms most of the day, more days than not, for at least 2 years. While
chronic depressive conditions were tradi-tionally conceptualized as
characterological and amenable to psychotherapy and resistant to
pharmacotherapy, recent phar-macologic trials of antidepressants as well as
depression-spe-cific psychotherapy have demonstrated effectiveness in the
overall treatment of DD. Both focused interpersonal and varia-tions of cognitive–behavioral
psychotherapy have demonstrated response in dysthymia. Individuals with DD have
a substantial risk for the development of MDD. This highlights the impor-tance
of early assessment and treatment to minimize subsequent long-term complications.
If signs and symptoms of DD follow a MDD, then a diag-nosis of MDD, in
partial remission, is made. A diagnosis of DD can be made if the individual
develops full remission of MDD for 6 months and subsequently develops signs and
symptoms of DD which then last a minimum of 2 years. In contrast, the diagnosis
of chronic MDD is made when an episode of MDD meets full criteria for MDD
continuously for at least 2 years. If DD has been present for at least 2 years
in adults (or 1 year in children and ado-lescents) and is subsequently followed
by a superimposed MDD, then both DD and MDD are diagnosed, which is often
referred to as “double depression”. The following specifiers apply to DD as
noted in DSM-IV:
· Early onset – if the onset of dysthymic symptomsoccurs be-fore age 21.
· Late onset – if the onset of dysthymic symptoms occurs at age 21 or
older, and with atypical features.
Atypical features refer to a pattern of symptoms which include mood
reactivity and two of the additional atypical symp-toms (i.e., weight gain or
increased appetite, hypersomnia, leaden paralysis, or interpersonal rejection
sensitivity). Early-onset DD is usually associated with subsequent episodes of
MDD. DD with atypical features may herald a bipolar I or II course.
Ongoing studies have not completely clarified the distinc-tion between DD and depressive personality disorder. Depressive temperaments may predispose an individual to a condition within the spectrum of Axis I mood disorders. However, it may not be specifically associated with MDD. This depressive temperament may also be associated with vulnerability to bipolar disorder.
A lifetime prevalence of 4.1% for women and 2.2% for men was reported
for DD (Weissman et al., 1988). In
adults, DD is more common in women than in men. In children DD occurs equally
in both sexes. Across both women and men, DD has a 2.5% 12-month prevalence
(Kessler et al., 1994, 2005).
Individuals with early-onset DD are at substantial risk for de-velopment
of other psychiatric conditions including alcohol or substance dependence, MDD
and personality disorders. Up to 15% of patients with DD may also have a
substance use pattern that meets criteria for comorbid alcohol or substance
dependence diagnosis. The most common associated personality disorders include
mixed, dependent and borderline. Childhood and ado-lescent-onset DD is
associated with a substantial risk for later occurrence of both MDD and bipolar
Sleep abnormalities demonstrate reduced REM latency, increased REM
density, reduced slow wave sleep and impaired sleep con-tinuity in 25 to 50% of
individuals with DD. There are minimal data on cortisol or thyroid
abnormalities in individuals with DD. Other neurobiological studies have not
yielded consistent results.
The diagnosis of DD cannot be made, if depressive symptoms occur during
the course of a nonaffective psychosis such as schizophrenia, schizoaffective
disorder, or delusional disorder. Diagnosis of depressive disorder NOS is made
if there are symp-toms which meet criteria for MDD during the residual phase of
a psychotic disorder. If DD is determined to be etiologically related to a
chronic medical condition, then one diagnoses secondary mood disorder due to a
general medical condition. If substance dependence is judged to be the
etiologic factor, then a substance-induced mood disorder is diagnosed.
Individuals with DD often have cooccurring personality disorders and in these
situations separate diagnoses on Axis I and II are made.
Dysthymic disorder often begins in late childhood or early ado-lescence
and by definition takes a chronic course. The risk for development of MDD among
children who have DD is significant because childhood onset of DD is an early
marker for recurrent mood disorder, both recurrent MDD and bipolar disorder.
The course of DD suggests impairment in functional sta-tus including
social and occupational, and physical function-ing. Patients who have both DD
and MDD have more severe functional impairment. Untreated DD contributes to
significant occupational and financial burden. There is substantial reduc-tion
in activity, more days spent in bed, more complaints of poor general medical
health, and more disability days than reported in the general population.
The treatment goals in DD are similar to those in MDD. They include full
remission of symptoms and full psychosocial recovery.