Diagnosis

Diagnosis is based on the self-reported experiences of an individual as well as abnormalities in behavior reported by family members, friends or co-workers, followed by secondary signs observed by a psychiatrist, nurse, social worker, clinical psychologist or other clinician in a clinical assessment. There are lists of criteria for someone to be so diagnosed. These depend on both the presence and duration of certain signs and symptoms. Assessment is usually done on an outpatient basis; admission to an inpatient facility is considered if there is a risk to oneself or others. The most widely used criteria for diagnosing bipolar disorder are from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, the current version being DSM-IV-TR, and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems, currently the ICD-10. The latter criteria are typically used in Europe and other regions while the DSM criteria are used in the USA and other regions, as well as prevailing in research studies. The DSM-V, to be published in 2013, will likely include further and more accurate sub-typing.

An initial assessment may include a physical exam by a physician. Although there are no biological tests which confirm bipolar disorder, tests may be carried out to exclude medical illnesses such as hypo- or hyperthyroidism, metabolic disturbance, a systemic infection or chronic disease, and syphilis or HIV infection. An EEG may be used to exclude epilepsy, and a CT scan of the head to exclude brain lesions. Investigations are not generally repeated for relapse unless there is a specific medical indication.

Bipolar spectrum

Bipolar spectrum refers to a category of mood disorders that feature abnormally elevated or depressed mood. These disorders range from bipolar I disorder, featuring full-blown manic episodes, to cyclothymia, featuring less prominent hypomanic episodes, to "subsyndromal" conditions where only some of the criteria for mania or hypomania are met. These disorders typically also involve depressive symptoms or episodes that alternate with the elevated mood states, or with mixed episodes that feature symptoms of both.The concept of the bipolar spectrum is similar to that of Emil Kraepelin's original concept of manic depressive illness. Currently, manic depressive illness is usually referred to as bipolar disorder or simply bipolar. A simple nomenclature system was introduced in 1978 to classify more easily individuals' affectedness within the spectrum.

Points on the spectrum using this nomenclature are denoted using the following codes:

·         M—severe mania

·         D—severe depression (unipolar depression)

·         m—less severe mania (hypomania)

·         d—less severe depression

Thus, mD represents a case with hypomania and major depression. A further distinction is sometimes made in the ordering of the letters, to represent the order of the episodes, where the patient's normal state is euthymic, interrupted by episodes of mania followed by depression (MD) or vice versa (DM).

Employing this schema, major depression would be denoted D. Unipolar mania (M) is, depending on the authority cited, either very rare, or nonexistent with such cases actually being Md.

Unipolar hypomania (m) without accompanying depression has been noted in the medical literature. There is speculation as to whether this condition may occur with greater frequency in the general, untreated population; successful social function of these potentially high-achieving individuals may lead to being labeled as normal, rather than as individuals with substantial dysregulation.

Criteria and subtypes

There is no clear consensus as to how many types of bipolar disorder exist. In DSM-IV-TR and ICD-10, bipolar disorder is conceptualized as a spectrum of disorders occurring on a continuum. The DSM-IV-TR lists three specific subtypes and one for non-specified:

Bipolar I disorder

One or more manic episodes. Subcategories specify whether there has been more than one episode, and the type of the most recent episode. A depressive or hypomanic episode is not required for diagnosis, but it frequently occurs.

Bipolar II disorder

No manic episodes, but one or more hypomanic episodes and one or more major depressive episode. Hypomanic episodes do not go to the full extremes of mania (i.e., do not usually cause severe social or occupational impairment, and are without psychosis), and this can make bipolar II more difficult to diagnose, since the hypomanic episodes may simply appear as a period of successful high productivity and is reported less frequently than a distressing, crippling depression.

Cyclothymia

A history of hypomanic episodes with periods of depression that do not meet criteria for major depressive episodes. There is a low-grade cycling of mood which appears to the observer as a personality trait, and interferes with functioning.

Bipolar disorder NOS (not otherwise specified)

This is a catchall category, diagnosed when the disorder does not fall within a specific subtype. Bipolar NOS can still significantly impair and adversely affect the quality of life of the patient.

The bipolar I and II categories have specifiers that indicate the presentation and course of the disorder. For example, the "with full interepisode recovery" specifier applies if there was full remission between the two most recent episodes.

Rapid cycling

Most people who meet criteria for bipolar disorder experience a number of episodes, on average 0.4 to 0.7 per year, lasting three to six months. Rapid cycling, however, is a course specifier that may be applied to any of the above subtypes. It is defined as having four or more episodes per year and is found in a significant proportion of individuals with bipolar disorder. The definition of rapid cycling most frequently cited in the literature (including the DSM) is that of Dunner and Fieve: at least four major depressive, manic, hypomanic or mixed episodes are required to have occurred during a 12-month period. Ultra-rapid (days) and ultra-ultra rapid or ultradian (within a day) cycling have also been described. The literature examining the pharmacological treatment of rapid cycling is sparse and there is no clear consensus with respect to its optimal pharmacological management.