Abnormal Psychology

196 CHAPTER 6

Because of the high comorbidity between depression and anxiety disorders

(about 50%), researchers propose that the two types of disorders have a common

cause, presently unknown. We will further discuss reasons for the high comorbid-

ity between these two types of disorders when we consider anxiety disorders in

Chapter 7.

Specifi ers

The DSM-IV-TR criteria list includes specifi ers—specifi c sets of symptoms that occur

together or in particular patterns. Specifi ers help clinicians and researchers identify

or note variants of a disorder, which is important because each variant may respond

best to a particular treatment or have a particular prognosis. For instance, depression

withmelancholic features includes complete anhedonia—the patient doesn’t feel any

better after positive events. When a patient experiences depression with melancholic

features, the symptoms usually fl uctuate during the day—he or she typically wakes

early in the morning, feels worse in the morning, and loses his or her appetite. In

contrast,atypical depression is characterized by depressed mood that brightens when

good things happen, along with at least two of the following: hypersomnia, increased

weight gain, heavy feelings in arms or legs, and persistent sensitivity to perceived

rejection by others (American Psychiatric Association, 2000). Atypical depression is

likely to respond to different medications than is depression with melancholic features

(Rosenbaum et al., 2005).

Symptoms of depression may also include catatonic features, which are specifi c

motor symptoms—rigid muscles that hold odd postures for long periods of time, or

a physical restlessness. Although not common, depression can occur with psychotic

Table 6.3 • Major Depressive Disorder Facts at a Glance

Prevalence

• Around 10–25% of women and 5–12% of men will develop MDD over their lifetimes. Before
  puberty, however, boys and girls develop MDD in equal numbers (Kessler et al., 2003).


• People with different ethnic backgrounds, education levels, incomes, and marital statuses are
  generally affl icted equally over their lives (American Psychiatric Association, 2000; Kessler et al.,
  2003; Weissman et al., 1991).

Comorbidity

• Most people with MDD also have an additional psychological disorder (Rush et al., 2005),
  such as an anxiety disorder (Barbee, 1998; Kessler et al., 2003) or substance abuse (Rush
  et al., 2005).

Onset

• MDD can begin at any age, with the average age of onset in the mid-20s, although people are
  developing MDD at increasingly younger ages.

Course

• Among individuals who have had a single MDE, approximately 50–65% will go on to have a sec-
  ond episode (Angst et al., 1999; American Psychiatric Association, 2000; Solomon et al., 2000).


• Those who have had two episodes have a 70% chance of having a third, and those who have
  had three episodes have a 90% chance of having a fourth.

Gender Differences

• As noted above, women are almost twice as likely as men to develop MDD (American
  Psychiatric Association, 2000; Kessler, 2003).


• Some women report that depressive symptoms become more severe premenstrually.
  Source: Unless otherwise noted above, the source for information is American Psychiatric Association, 2000.