Depression - Comorbidity

Anxiety
The different types of Depression and Anxiety are classified separately by the DSM-IV-TR, with the exception of hypomania, which is included in the bipolar disorder category. Despite the different categories, depression and anxiety can indeed be co-occurring (occurring together, independently, and without mood congruence), or comorbid (occurring together, with overlapping symptoms, and with mood congruence). In an effort to bridge the gap between the DSM-IV-TR categories and what clinicians actually encounter, experts such as Herman Van Praag of Maastricht University have proposed ideas such as anxiety/aggression-driven depression. This idea refers to an anxiety/depression spectrum for these two disorders, which differs from the mainstream perspective of discrete diagnostic categories.

Although there is no specific diagnostic category for the comorbidity of depression and anxiety in the DSM or ICD, the National Comorbidity Survey (US) reports that 58 percent of those with major depression also suffer from lifetime anxiety. Supporting this finding, two widely accepted clinical colloquiallisms include


 * agitated depression - a state of depression that presents as anxiety and includes akathisia, suicide, insomnia (not early morning wakefulness), nonclinical (meaning "doesn't meet the standard for formal diagnosis") and nonspecific panic, and a general sense of dread.


 * akathitic depression - a state of depression that presents as anxiety or suicidality and includes akathisia but does not include symptoms of panic.

It is also clear that even mild anxiety symptoms can have a major impact on the course of a depressive illness, and the commingling of any anxiety symptoms with the primary depression is important to consider. A pilot study by Ellen Frank et al., at the University of Pittsburgh, found that depressed or bipolar patients with lifetime panic symptoms experienced significant delays in their remission. These patients also had higher levels of residual impairment, or the ability to get back into the swing of things. On a similar note, Robert Sapolsky of Stanford University and others also argue that the relationship between stress, anxiety, and depression could be measured and demonstrated biologically. . To that point, a study by Heim and Nemeroff et al., of Emory University, found that depressed and anxious women with a history of childhood abuse recorded higher heart rates and the stress hormone ACTH when subjected to stressful situations.

Hypomania
Hypomania, as the name suggests, is a state of mind or behavior that is "below" (hypo) mania. In other words, a person in a hypomanic state often displays behavior that has all the earmarks of a full-blown mania (e.g., marked elevation of mood that is characterized by euphoria, overactivity, disinhibition, impulsivity, a decreased need for sleep, hypersexuality), but these symptoms, though disruptive and seemingly out of character, are not so pronounced as to be considered a diagnosably manic episode.

Another important point is that hypomania is a diagnostic category that includes both anxiety and depression. It often presents as a state of anxiety that occurs in the context of a clinical depression. Patients in a hypomanic state often describe a sense of extreme generalized or specific anxiety, recurring panic attacks, night terrors, guilt, and agency (as it pertains to codependence and counterdependence). All of this happens while they are in a state of retarded or somnolent depression. This is the type of depression in which a person is lethargic and unable to move through life. The terms retarded and somnolent are shorthand for states of depression that include lethargy, hypersomnia, a lack of motivation, a collapse of ADLs (activities of daily living), and social withdrawal. This is similar to the shorthand used to describe an "agitated" or "akathitic" depression.

In considering the hypomania-depression connection, a distinction should be made between anxiety, panic, and stress. Anxiety is a physiological state that is caused by the sympathetic nervous system. Anxiety does not need an outside influence to occur. Panic is related to the "fight or flight" mechanism. It is a reaction, induced by an outside stimulus, and is a product of the sympathetic nervous system and the cerebral cortex. More plainly, panic is an anxiety state that we are thinking about. Finally, stress is a psychosocial reaction, influenced by how a person filters nonthreatening external events. This filtering is based on one's own ideas, assumptions, and expectations. Taken together, these ideas, assumptions, and expectations are called social constructionism.

On a final note, researchers at the University of California, San Diego, under the guidance of Hagop Akiskal MD, have found convincing evidence for the co-occurrence of hypomanic symptoms associated with a diagnosis of depression where the diagnosis does not meet criteria for Bipolar Disorder. Symptoms under consideration, such as irritability, misdirected anger, and compulsivity, also may not present sufficiently to be considered a hypomanic episode, as described by a Bipolar II Disorder. As noted in the Frank study mentioned above, this particular course of the disease, with the breakthrough of anxiety, may have a significant impact on the overall course of the depression.

This idea of co-occurring anxiety and depresion is supported in a study by Giovanni Cassano MD of the University of Pisa and his collaborators on the Spectrum Project, who found a correlation between lifetime hypomanic and manic symptoms and the severity of the depression.


 * "The presence of a significant number of manic/hypomanic items in patients with recurrent unipolar depression seems to challenge the traditional unipolar-bipolar dichotomy."

These authors, along with many other researchers, argue in support of a revision of the approach to psychiatric diagnosis into what is being called the mood spectrum, so as to "[make] more accurate diagnostic evaluation[s]." This approach, although controversial, has begun to be given consideration by many behavioral health professionals.