Introduction
Atypical depression (AD) is a common condition in clinical practice. Instead of the classical symptoms of melancholic depression, AD is characterized by hyperphagia, hypersomnia, and rejections sensitivity. Exacerbations are often triggered by perceived interpersonal slights and heightened social rejection. Rejection sensitivity, though painful, may once have been a useful social instinct that encouraged inoffensive behavior and thus promoted social harmony.
AD is the most common type of clinical depression in bipolar I disorder (previously known as manic depression). This serious disorder frequently leads to hospitalization, and, when untreated, can have long-term effects on career and social life. AD may be ongoing between manic periods, but episodic and of variable intensity. AD can also occur without mania or be associated with such other syndromes as personality disorders and panic anxiety. Early and accurate recognition and treatment of AD and bipolar I disorder are important for best clinical practice.
This chapter addresses clinical characteristics and associations of AD, in order to facilitate diagnosis and treatment, and clarify relationships to psychotic manifestations ( Table 7.1 ).
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Atypical Depression
The term AD was initially chosen to contrast classical melancholic depression ( Chapter 6 ) with another depressive syndrome that has a specific symptom profile of reversed vegetative symptoms. The more classical (melancholic, agitated, “endogenous”) presentations of depression were the norm at a time when depression was infrequently diagnosed in outpatients, and almost never in adolescents or younger adults.
Importantly, the word “atypical” had also been used to describe depressive presentations that were out of the ordinary. But as the concept of AD has evolved over the years, it no longer connotes an uncommon or unusual clinical presentation. Indeed, the use of AD as a specific type of depression was codified in clinical psychiatry with the publication of the Diagnostic and Statistical Manual for Mental Disorders Fourth Edition (DSM-IV).
DSM-IV introduced formal criteria for “atypical features” as a modifier for both major depression and dysthymia, and these criteria are retained in DSM5. When there is a diagnosis of major depression or dysthymia, a diagnosis of AD requires the presence of the DSM5 specifiers for atypical features, when the features predominate during the majority of days of the current or most recent major depressive episode or of a persistent depressive disorder. Clinically, AD is common both in unipolar depressions and, together with mania, in bipolar disorders.
Diagnostic criteria
According to the DSM5, the criteria for depressive disorders with atypical features include the following ( Table 7.2 ).
Specify if:
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As noted above, mood reactivity is a main symptom of AD. One study showed that the most common symptom reported by patients with AD was mood reactivity, at 89% to 90%, but other symptoms (rejection sensitivity, leaden paralysis, and hypersomnia) were nearly as common, 78% to 89%. This has led to further work, suggesting that AD could be diagnosed with comparable validity if only three of the first five inclusion criteria (including mood reactivity) are present, or just two of the four criteria if mood reactivity is excluded.
It has also been proposed that pathologic sensitivity to perceived interpersonal rejection is a core feature of AD. Rejection sensitivity can lead to significant social or occupational impairment. Understanding the full clinical picture of AD includes awareness of mood and physiological and psychological symptoms. With that perspective, AD typically persists or recurs in varying degree over an extended time scale.
Prevalence, course, and comorbidity
Estimates of AD prevalence in depressed patients range from 15.7% to 43%. In community samples, the prevalence of AD based on reversed neurovegetative symptoms was in the range of 11% to 16% and about 6.5% of people with major depression met the criteria for AD. Seasonal affective disorder (SAD) and AD have overlapping symptom pictures, and may reflect differing presentations of the same underlying pathophysiology.
AD is associated with a range of emotional, physical, sexual, financial, and catastrophic hardships across the life span. This painful course of AD has important implications for health care utilization and costs. AD’s commonplace psychiatric comorbidities can include panic anxiety, social anxiety, eating disorders, and substance-related disorders along with such self-reported diagnoses as schizophrenia and autism spectrum disorders. Whether or not AD occurs with a broader mood disorder, there is increased risk of suicidal thought, suicide attempts, medically significant weight gain, substance use, social withdrawal, and interpersonal problems with family members, intimate partners, schoolmates, teachers, coworkers, or employers.
Individuals with AD are also more likely to experience socioeconomic disadvantage than depressed individuals without AD. The combination of AD and bipolar disorder increases the risk of substance abuse and somatization disorder. Each of these other diagnoses, life events, and interpersonal factors most likely contribute to the adverse consequences of AD.
AD is more commonly diagnosed in women, especially younger women. Women have a younger age of onset, more depressive episodes, greater functional impairment, and more adverse life events such as psychological trauma. As with some other psychiatric diagnoses, it is possible that women are on average more likely than men to reveal emotional distress or to seek help.
Atypical depression and bipolar disorder
Perhaps most importantly for psychosis comorbidity, patients with AD are more likely to experience a lifetime bipolar I manic episode. In discussing bipolar disorders, it is important that the older manic-depressive diagnostic name required episodes of true mania, and roughly corresponds to what is now called bipolar I disorder. In addition, milder degrees of increased mood variation are considered bipolar II. Some authors consider AD as part of this broadly defined “bipolar spectrum.” Other studies suggest a considerable overlap of AD manifestations with borderline personality disorder and with bipolar spectrum disorder. When adopting moderately strict criteria for bipolar spectrum disorders based on DSM-IV, 24% of AD patients could be classified as bipolar, while broader bipolar criteria produced a prevalence of 72% in another AD sample (major depression with atypical features). Furthermore, studies of bipolar disorders have found comorbid AD with prevalence rates as high as two-thirds. A Polish cross-sectional study of depression found a significantly higher frequency of AD symptoms (hypersomnia and hyperphagia) in the bipolar patients as compared to the unipolar patients.
Importantly, research has found that those with AD have significantly higher rates of bipolar I disorder than those without atypical features. AD-diagnosed patients seen in clinical practice had a higher family history prevalence of bipolar disorder compared to those without AD. AD symptoms may also be more pronounced in those patients with bipolar disorder. Male bipolar patients compared with unipolar depressed ones had significantly more episodes of AD (OR 2.82). Another study compared bipolar depression patients to unipolar depression patients and found a significant increase in state rejection sensitivity when depressed. Increased rejection sensitivity when depressed further supports AD-like bipolar depression over unipolar depression. Another piece of evidence for this is that bipolar I subjects report increased seasonal changes in social activity and in weight. Simonsen et al. also observed that bipolar subjects slept significantly more throughout the year, and slept for a mean of 1.8 hours more in winter than in summer.
Atypical depression and personality disorders
AD is also associated with certain personality disorders. The tendency to anticipate rejection and failure, and the consequent tendency to give up easily when frustrated, is a characteristic of avoidant personality (passive, timid, submissive, easily hurt). Borderline personalities are emotionally unstable, self-destructively impulsive, chronically bored or angry, with constantly shifting moods. Histrionic personalities are flamboyant, self-dramatizing, self-centered, and emotionally shallow. These personality descriptions reflect different styles of coping with the rejection sensitivity and mood reactivity of AD. However, a narrow focus on associated personality disorders lead to diagnostic omission. Research suggests that AD may be a missed diagnosis in personality disorders such as borderline, histrionic, or avoidant. One reason for that is that the longer an episode of depression lasts—and AD can be lifelong—the more it begins to look like personality, with the rejection sensitivity of AD appearing to be merely a personality trait rather than a concurrent emotional trait. Although AD improves with medication, an associated personality disorder untreated by psychotherapy might moderate, but would likely continue.
Bipolar I Mania
Fluctuations in mood are common in life, particularly when faced by stressful events. Nevertheless, when mood swings are striking and persistent, and result in notable distress or impairment, there could be an underlying affective disorder. As above, the bipolar spectrum disorders reflect the extent and severity of mood elevation, from unipolar to bipolar II to bipolar I. Individuals with unipolar disorder present with depressive episodes only, and those with bipolar II or I disorder show increasingly pronounced episodes of mood elevation.
In the DSM-5, the modern bipolar I differs from the classic manic depression only to the extent that neither psychosis nor the lifetime experience of major depression is required. However, the vast majority of individuals whose symptoms meet full criteria for a true manic episode do also experience major depression during the course of their lives. Manic episodes are frequently preceded by or followed by hypomanic or major depressive episodes. Manic episodes commonly include grandiose delusions, and sometimes include other delusions and auditory hallucinations.
The “bipolar depressive” phases of bipolar I disorder typically have AD symptoms and course. Bipolar depression and AD are characterized by mood reactivity and often by the atypical physical symptoms of oversleeping and overeating. Especially when milder, bipolar depressive symptoms can be difficult to distinguish from depression with atypical features. Some research suggests that a family history of bipolar disorder is more likely in depressed people with the atypical symptoms of leaden paralysis and oversleeping. Hypersomnia is an important clinical feature of both bipolar depression and AD. In another study, leaden paralysis, increased appetite, weight gain, and rejection sensitivity (common symptoms in AD) were more often seen in bipolar patients ( Table 7.3 ).
| For a diagnosis of bipolar I disorder, it is necessary to meet the following criteria for a manic episode. The manic episode may have been preceded by and may be followed by hypomanic or major depressive episodes. |
| Manic Episode |
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