Problems in the current concepts and definitions of bipolar disorders
Authors: JULES ANGST
Journal: World Psychiatry (2011)

One can only agree with the conclusion of Strakowski et al that future changes to the current definitions of bipolar disorders should be based on consistent and converging evidence of their validity; but this also applies to the existing definitions. My remarks are complementary and focus mainly on DSM-IV mood disorders. Changes can be recommendable for several reasons: a) some current diagnostic criteria for bipolarity (mania/hypomania) may not base on clinical evidence and not be valid; b) the current diagnostic spectrum of major mood disorders may be considered invalid (in its over-diagnosis of major depressive disorders at the expense of bipolar disorder) or regarded as illogical (labelling unipolar mania/hypomania as bipolar disorder but unipolar depression as major depressive disorder); c) the current DSM-IV severity spectrum is insufficient in its coverage: more than 50% of patients treated professionally for depression do not meet formal criteria for DSM-IV mood disorders 1 but are allocated to the fuzzy category "not otherwise specified". ICD-10's severity spectrum performs better in this respect and is much closer to nature. The DSM-III introduced the term "mood disorders", which suggests that mood changes are the only main symptoms, neglecting for instance increased energy/activity. The latter is frequently more clearly perceived and reported by hypomanic patients themselves than is irritability (often better observed by others). The Zurich Study and the Bridge Study demonstrated the validity of increased energy/activity as a gate question in addition to elevated or irritable mood. Even more important is the finding that the exclusion criteria for manic and hypomanic episodes screen out patients who show all the typical bipolar characteristics (positive family history for mania, early onset, high recurrence, course progression, and high comorbidity with panic, generalized anxiety disorder, social phobia, obsessive-compulsive disorder, binge eating, substance use and borderline personality disorders). It has been shown that conversions from depression to hypomania under antidepressants are not a simple unwanted effect of the treatment 2 but a natural consequence of response. The draft DSM-5 has, to some extent, taken heed of these findings. A third problem with the current DSM-IV concept is the 4-day duration criterion for hypomanic episodes; brief episodes are common and typical, especially in adolescents and between major episodes in adults. The 4-day criterion is not data based and is therefore questionable 3. The spectrum from depression to mania has been only partially explored by representative epidemiological research, mainly because the interviews used assume that the DSM-IV concept is correct; this top-down approach excludes important information. A continuum of depressive and manic symptoms was shown by Cassano et al 4, who examined patients with major depressive disorders. Recent re-analyses of two large epidemiological studies have demonstrated that roughly 40% of subjects with major depressive disorders manifest subthreshold bipolar syndromes with the corresponding validity and comorbidity 5,6. This group of depressed subjects is at great risk of developing full-blown bipolar I and II disorders. There are as yet no treatment data on such patients; but, in contrast to the results from the STAR*D study reported by Strakowski et al, two multicentre studies from France and Poland demonstrated that treatment-resistant depression was highly correlated with bipolarity as assessed by the Hypomania Checklist-32 R 7,8. An unsolved nosological problem is pure mania and hypomania, which seem to differ from bipolar disorders as regards family history (negative for depression) and other important characteristics. There exist almost no data on this aspect 9. The severity aspect of the two-dimensional spectrum concept 10 has long been the spectrum view, going back to the work of Klerman 11 and Akiskal 12. The current DSM-IV diagnostic classification is still incomplete in its coverage of treated patients. Minor and recurrent brief depression appear only as subjects for further study in the appendix. Cyclothymic disorders are included, but only as a more chronic condition. Acute recurrent and minor depression and minor bipolar disorders should be incorporated instead of being allocated to the ragbag "not otherwise specified". Operational definitions would then allow precise diagnoses of most of the treated patients, providing clinical/epidemiological research with important data for future diagnostic developments. On the other hand, tendencies to merge personality traits or disorders (borderline personality disorder) or temperaments (cyclothymic, hyperthymic, depressive) with bipolar and depressive diagnostic concepts need approaching with caution. These traits are very closely associated with bipolar disorders but should nonetheless be considered as a third spectrum dimension, not to be mixed with the severity or diagnostic spectra. Diagnostic manuals are essential but will need constant improvement. To enable the collection of the necessary information for further data-based changes, the manuals should include (not just in an appendix) potential new categories and should encourage a patient-centred, bottom-up approach to examination and diagnosis. This would register first and foremost the patients' complaints without the restricting lenses of diagnostic concepts. The same, of course, applies to standardized epidemiological assessments. Important, here, is to make gate questions broader in order to avoid false negatives. Finally, causation is always multifactorial and, at our present stage of knowledge, to a certain extent arbitrary. Exclusion criteria based on causal attributions should, if possible, be avoided.