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EVOLUTION OF THE CONCEPT OF BIPOLAR DISORDERS IN DSM:

The concept of bipolar disorder grew out of Emil Kraepelin’s classification of manic depressive insanity, which was postulated around the end of the 19th century. In 1966 Angst and Perris independently demonstrated that unipolar depression and bipolar disorder could be differentiated in terms of clinical presentation, evolution, family history and therapeutic response. Their ideas stood the test of time and became assimilated in both the two main modern systems of classification for the diagnosis of mental disorder: the DSM and the ICD.

In the first DSM, published in 1952, bipolar disorder diagnoses were strongly influenced by the psychodynamic approach which provided no sharp distinction between normal and abnormal states. All disorders were considered reactions of the personality to psychological, environmental, and biological factors, with mental disorders existing on a continuum of behavior.

The DSM-II was published in 1968 and continued to define mental disorders from a largely theoretical psychodynamic perspective. In 1980, however, the third edition of the DSM was published, reflecting a radical change of perspective. A biomedical approach was substituted for the psychodynamic conceptualization, making way for a clear distinction between normal and abnormal behaviors and reformulating psychiatric illnesses in terms of empirical research and statistical knowledge.

It was in the DSM-III that the term 'bipolar disorder' replaced the older term 'manic depressive disorder'. It became recognised that not all patients who experience mania and depression become psychotic and therefore psychosis should not be required for a diagnosis. The new term, 'bipolar disorder' reflects the defining feature of mood polarity rather than simply pointing to the consequences of that polarity: mania and depression. Also, in the DSM-III, the distinction between adult and pediatric bipolar disorder diagnoses was indicated for the first time. This acknowledgment was the result of years of research suggesting that mainly Attention Deficit Disorder and other disorders to a lesser degree are predisposing factors for developing bipolar illness.

In the DSM-III-R (1987), further improvement was made to the diagnosis of bipolar depression as research about mood disorders and disorders of childhood and adolescence were added. Hence, this was the first time that bipolar diagnoses were supplemented with subtyped classifications such as Bipolar Disorder-Mixed, Bipolar Disorder-Manic, Bipolar Disorder-Depressed, Bipolar Disorder-Not Otherwise Specified, and Cyclothymia.

In the DSM-IV (1994) and the most recent DSM-IV-TR (DSM-IV-text revision, 2000), the definition of bipolar disorder diagnosis has evolved from a monolithic disorder with a single set of criteria, to a more nuanced subtype system, where Bipolar I and Bipolar II forms of the disorder are recognized and separately diagnosed. These two forms are distinguished primarily by the type of mania experienced by individuals - mania versus hypomania. In Bipolar I Disorder patients suffer from at least one manic episode and one depressive episode, while in Bipolar II Disorder, individuals experience at least one hypomanic episode and at least one major depressive episode. It is almost certain that the disorder will continue to be revised in future editions of the DSM, as research-informed knowledge about the nature of the illness continues to be uncovered.

STRENGTHS & WEAKNESSES OF THE DSM IV-TR CLASSIFICATORY SYSTEM ON BIPOLAR DISORDERS:

STRENGTHS:
-     Provides clinicians with a common universal language for identifying these disorders, in order to efficiently treat patients.

-     The diagnostic categories are very well-structured incorporating clear-cut subtypes, specifiers and severity indicators, thus leaving no ambiguity in making a specific diagnosis.

-     Each diagnostic entity has clearly defined diagnostic criteria. For example, there are well-defined criteria and guidelines for diagnosing each episode – depression, mania and hypomania and mixed.

-     Severity indicators (mild, moderate, severe) help the clinician make treatment plans according to the severity, as well as monitor progress. These severity indicators are absent for manic episodes in the ICD-10.

-     Additional subtypes signifying remission (partial remission or complete remission) are an added advantage while following up patients on treatment.

-     According to the DSM IV-TR, Bipolar 1 disorder can be diagnosed with just one manic episode. This is in contrast with ICD-10, which requires at least two episodes, one of which has to be manic or hypomanic. This diagnostic aspect has treatment implications: People presenting with the first manic episode are more to receive a mood stabilizer when classified as “Bipolar disorder” using the DSM criteria. These patients would not be classified as “Bipolar disorder” if ICD-10 criteria were used.

-     Inclusion of the Bipolar 2 category is unique to DSM and this diagnostic category and concept is entirely absent in ICD. Many solid studies have shown that Bipolar-2 is a distinct clinical entity with even a distinct genetic or familial predisposition. This differentiation into Bipolar 1 and 2 makes treatment plans more targeted and appropriate.

-     The categorical approach to diagnosis (as opposed to a dimensional approach), gives high inter-rater reliability and validity during research, especially in epidemiological studies.

WEAKNESSES:

-     The strictly categorical approach undermines the fact that Bipolar disorders often exist in a continuum. Of late this concept is gaining more ground with more proposed categories of Bipolar disorders (1 to 6; Young and Klerman.) More ‘softer’ forms of bipolar disorder have been proposed, including recurrent depressive episodes with a hyperthymic temperament and a family history of bipolar disorder (Akiskal et al., 2000)

-     Some clinicians find this classification into separate sub-categories as “excessive” or “over-categorized”. For example, Bipolar 1 itself has 30 distinct diagnostic codes!!! For example, even a manic episode (which by clinical definition itself causes significant disruption and socio-occupational dysfunction) is sub-categorized as mild, moderate and severe! (So, how do you differentiate between a ‘mild manic episode’ and a hypomanic episode?)

-     Certain researchers (Galnter et al) have shown that there are problems with the validity of the diagnostic criteria itself, especially with children and adolescents. The DSM-IV-TR criteria for a manic episode and bipolar disorder (BD) were developed for adults but are used for children. The manner in which clinicians and researchers interpret these criteria may have contributed to the increase in Bipolar Disorder diagnoses given to youth. There also seem to be differences between the DSM-IV-TR manic episode criteria and descriptive text.


DIFFERENTIATION BETWEEN BIPOLAR 1, 2 & CYCLOTHYMIA:

Bipolar I Disorder:

To be diagnosed as Bipolar I, an individual must have at least one manic or mixed episode (lasting for at least a week) within his or her lifetime. A depressive episode is not required in order to warrant a dianosis of Bipolar I, although most people usually have multiple depressive episodes.

Bipolar II Disorder:

In order to receive a diagnosis of Bipolar II Disorder, one must have had at least one hypomanic episode and at least one depressive episode within his or her lifetime. The patient must have never had a manic episode.

Cyclothymic Disorder:

To be diagnosed with Cyclothymic Disorder, one must have experienced, over a period of two years (one year for children and adolescents), numerous periods of time with hypomanic symptoms as well as periods of depressive symptoms that do not XXXXXXX the criteria for Major Depressive Episode. More than half of the days need to be either high or low, and all periods of wellness need to last for less than 2 months. The person must never have had a manic episode.

Regards,
Dr. Jonas Sundarakumar
Consultant Psychiatrist

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