There is an increasing recognition that many individuals treated as unipolar depression might be actually having bipolar disorder. There are many reasons for this. Having a hypomanic/manic/mixed episode is the key factor in making a diagnosis of bipolar disorder.Patients with bipolar disorder spent more time in depression (and more distressing) and are likely to seek help/report depression more often. Patients might consider hypomania / brief elevated mood as a relief from the darker periods of depression or as returning back to normality and may not report these to doctors unless specifically explored. Patients enjoy the elevated mood and sometimes would hide this information for fear of psychiatrists ‘taking it away’ from them. While in manic episodes, patients are usually brought in for treatment by others, and miss diagnosis of schizoaffective disorder is possible at that stage.Psychiatrists may not be exploring the full range of experiences, ideas and behaviours in a comprehensive manner in these patients.
The bipolar nature is often not recognised for many years. Some studies have shown that the average period of time from onset of illness until beginning of medication for prophylaxis for bipolar is approximately 10 years (Baethge et al., 2003). This have serious consequences: 1. Prophylaxis has a crucial role in bipolar disorder and this is missed 2.Untreated/unidentified hypomanic episodes create serious troubles in the individual’s life 3. Continued antidepressant monotherapy can be detrimental in bipolar disorder.
Over the years, studies show an increasing prevalence of bipolar spectrum disorder among patients treated as Unipolar depression.This has ranged between one and six percent (Bauer and Pfennig, 2005; Hirschfeld et al., 2003; Kessler et al., 2005; Merikangas et al., 2007) to 40% percent (Angst et al., 2010). The training of the diagnosing doctor and the degree of stringency of the diagnostic criteria used contributes to this difference.
BRIDGE study (Bipolar Disorder: Improving Diagnosis Guidance and Education) is the largest study on the prevalence of bipolar disorder in patients with an acute major depressive episode conducted so far with 5635 patients from 521 treatment centers in 18 countries in Africa, Asia and Europe. When strict DSM criteria is used only 16% of the depressed had an actual diagnosis of bipolar disorder. In the same group of patients a new expanded set of criteria (bipolarity disorder algorithm) identified 47% of them were identified as bipolars.( Angst et al., 2011).
There is currently no complete consensus on diagnostic criteria for bipolar disorder. Many argue for an expanded criteria than the current DSM one. This article examines the rates of bipolar disorder in a cohort of patients diagnosed as depression using different criteria. Bschor, Angst and colleagues wanted to see the impact of a wider range of diagnostic concepts differing in stringency or broadness on the prevalence of bipolar disorders in the German sub sample of the above study.
252 adult patients with a diagnosis of major depression were included. (2008–2009).60% were inpatients. 63 % were females. Half had first presentation before age 40. 28% had attempted suicide at least once. Nearly one third had total of 7 or more episodes, and 22% were experiencing their first episode. 90% were on antidepressants.
All patients underwent the following diagnostic process
1.Physician’s diagnosis: Known bipolar disorder, type I/type II: Yes/No.
2. DSM-IV criteria for manic or hypomanic episodes : Criteria checklist filled out by the study physician.
3.Modified DSM-IV criteria: Corresponding with the DSM-IV criteria, but also allowing inclusion of substance/ antidepressant-induced (hypo)manias.
4.Bipolarity Specifier Algorithm: DSM-IV criteria of ‘‘presence of at least three typical manic or hypomanic symptoms’’, with an amendment that these may also arise during a phase of increased activity without a recognizably altered mood and without the duration criteria of the DSM (at least one week for manic episodes, at least four days for hypomanic episodes). The changes must be regarded by others as foreign to the affected person’s personality or they must lead to clear social/occupational impairment noticeable to others or to inpatient/outpatient treatment.
5.HCL 32, a self rating tool, was used to identify bipolar II disorders and subsyndromal hypomania.
Prevalence of bipolar by different criteria
DSM 4 criteria: 11.6%
Physician’s diagnosis (Known Bipolar) : 18.4%
Modified DSM-IV criteria: 24.8%
Bipolarity Specifier Algorithm:40.6%
HCL-32R : 58.7%
In the 204 patients with a physician’s diagnosis of unipolar disorder, 12 had DSM 4 bipolar disorder, 33 had modified DSM bipolar diagnosis, and 67 were positive according to Bipolarity Specifier Algorithm.
1.If substance and, in particular, antidepressant-induced hypomanic or manic episodes are also accepted as defining elements for the diagnosis of bipolar disorder (ie modified DSM-IV criteria), the rate of bipolar diagnoses increases to more than twice that of the original DSM-IV criteria.
2. Diagnostic agreement between the physician’s diagnosis and a criteria based approach is poor.
3.The prevalence figures will be higher or lower depending on the accepted definition of the diagnosis ‘‘bipolar disorder’’
4. Prevalence varies according to criteria. The true test of these different approaches/ criteria would depend much on therapeutic results if they were to follow the guidelines valid for the assigned diagnosis.
Detailed and structured exploration of bipolarity is essential in all patients presenting with depression. Self assessment questionnaires like HCL32 can be used for screening to aid such comprehensive assessment.
Summary of the article:
Are bipolar disorders underdiagnosed in patients with depressive episodes? Results of the multicenter BRIDGE screening study in Germany. Bschor T, Angst J, Azorin JM, Bowden CL, Perugi G, Vieta E, Young AH, Krüger S. J Affect Disord. 2012 Dec 15;142(1-3):45-52.