The Bipolar Spectrum AUTHOR's PROOF

BRITISH JOURNAL OF PSYCHIATRY (2007), 190, 189^191. doi: 10.1192/bjp.bp.106.030957 EDITORIAL AUTHOR’ S P ROOF

The bipolar spectrum these can be considerably reduced by early diagnosis and treatment, as recently shown by McCombs et aletal (2006).(2006). JULES ANGST The underdiagnosis of mood disorders, especially bipolar disorders, is not confined to the clinical setting but may also apply to traditional epidemiological studies, which found lifetime prevalence rates of 0.5–2%. Some recent studies (Kessler et aletal, 2003;,2003; Lieb, 2006) comprising two or three inter- view waves have described growing lifetime prevalence rates for both major depressive Summary The two-dimensional of hypomania or mania, remains an uncer- episodes (19% to 24%) and for bipolar dis- bipolar spectrum described here tain diagnosis lifelong. Over decades of order types I and II together (about 2% to recurrent depressive illness, bipolar dis- 4%). An important question, then, is what comprises a continuum of severity from order may manifest at any time: a lifelong proportion of patients with major depres- normal to psychotic and a continuum from follow-up of patients hospitalised showed sion should in fact be diagnosed as having depression, via three bipolar subgroups to a persistent risk of diagnostic change to bipolar disorder: is it one-fifth or one-tenth mania.This combination of dimensional bipolar disorder of 1.25% per year of as generally reported, or as many as half, as and categorical principles for classifying observation. we have found? Bipolar affective disorder is a more mood disorders may help alleviate the severe disorder than major depression, as BIPOLAR SPECTRUM: problems of underdiagnosis and measured by higher lifelong recurrence AAMODELFORRESEARCH MODEL FOR RESEARCH undertreatment of bipolar disorders. and greater comorbidity with psychiatric AND CLINICAL PRACTICE disorders, especially anxiety and secondary Declaration of interest None.None. substance use disorders. In addition it is The development of a validated bipolar associated with serious somatic disorders spectrum concept can provide a more dif- Depression is very distressful, prompts the such as diabetes, hypertension and cardio- ferentiated research and treatment model depressed person to seek treatment and is vascular disease. This explains the corre- for affective disorders and may help reduce relatively easy to diagnose. Hypomania, spondingly higher mortality rates among the underrecognition of bipolarity. on the other hand, is often perceived as people with bipolar disorder, although the A dimensional concept (from normal to normal well-being and tends not to be suicide risk is lower in type I bipolar dis- pathological) was proposed by Kretschmer reported. There is wide agreement as to order than in depression (O(Osby¨ sby et aletal, 2001).,2001). in 1921 for schizophrenia (schizothymic – the difficulty of identifying hypomania in Correct diagnosis of bipolar illness is schizoid – schizophrenic) and for affective bipolar II and minor bipolar disorders: essential for appropriate treatment, espe- disorders (cyclothymic temperament – patients with bipolar depression report that cially long-term secondary prophylaxis. As cycloid ‘psychopathy’ – manic-depressive the recognition of their disorder was a consequence of their severity, unrecog- disorder) as well as by Bleuler (1922). The delayed by as much as 8–10 years. Unipolar nised bipolar disorders lead, moreover, to term ‘spectrum’ was first used in psychiatry depression, which is defined by the absence higher costs than major depression, but in 1968 for the schizophrenia spectrum,

Fig. 11Fig. Two-dimensional mood/affective spectrum (does not include schizoaffective disorder, as a transition to the schizophrenic spectrum).The precise relationship of personality disorders to the disease spectra is uncertain and an unsolved general problem of psychiatric classification. BP-I (-II), bipolar-I disorder type I (II); D, major depression, d, minor depression; M, mania; m, hypomania; MDD, major depressive disorder; RBD, recurrent brief depression; sx, symptoms

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which integrated schizoid personalities 2003). Most healthy people report depres- where clear distinctions between depressive, (Kety(Kety et aletal, 1968). In 1977 Akiskal pro- sive and hypomanic symptoms and many hyperthymic and cycloid (‘cyclothymic’) per- posed a cyclothymic–bipolar spectrum and are identifiable as manifesting depressive, sonality disorders are desirable. in 1981 Klerman suggested a mania spec- hypomanic and cyclothymic temperaments, trum (Akiskal, 1977; Klerman, 1981). which appear to predispose to the respective THE FUTURE Today the term ‘bipolar spectrum’ is affective disorders and personality disorders mainly used in two complementary senses (see Fig. 1). Only about 15% of the popu- It may take longer than hoped to develop (Fig. 1):(Fig.1): lation report no such symptom over their life- better-validated diagnostic criteria: apart time and are ‘super-normal’, with very low from genetic data, long-term follow-up (a)(a)aa spectrum of severity,which embraces scores for vegetative lability and neuroticism. studies over at least 10 years are needed psychotic and non-psychotic major and in order to approach diagnostic classifica- minor bipolar disorders (including tions that can be used as gold standards. bipolar dysthymia, recurrent brief and CASENESS For this reason the forthcoming ICD–11 minor depressions), cyclothymic disorders, hypomania and, at its broadest, The dimensional nature of the mood and DSM–V may again have to give us even borderline disorders and cyclo- spectrum raises the question of the correct definitions with a limited half-life. thymic temperament; cut-off levels for caseness (Wing et aletal,, Too many studies, especially in epide- 1978). The current concept of bipolar-II miology, have used methods tailored and (b)(b)aa proportional mood spectrum, whichwhich disorder requires a diagnosis of hypomania restricted to the current DSM–IV diagnostic considers the two components mania in addition to major depression. However, concepts and have not collected additional and depression, first on the level of the definition of hypomania is the subject data which would have allowed those major mood disorders – major depres- of much controversy and research. It is gen- concepts to be questioned – and too many sion (D) bipolar II disorder (Dm), erally agreed that the DSM–IV criteria journals and reviewers hesitate to accept bipolar I disorder (MD), mania with (American Psychiatric Association, 1994) papers that deviate methodologically from mild depression (Md) and pure mania are too strict (not sensitive) and not based the current diagnostic conservatism. At the (M) (Angst, 1978) – and then on the on empirical evidence (not validated). All other extreme, the promising bipolar spec- level of minor mood disorders: the aspects of the definition are under discus- trum concept can be discredited by uncritical corresponding categories are mild sion: the quality of the stem questions (cri- generalisations and over-inclusiveness, for depression (d), minor bipolar disorder terion A), which are restricted to elevated instance by taking for granted that cyclo- (md) and hypomania (m). and irritable mood (i.e. do not consider thymic personality or borderline disorders This proportional model is an extension symptoms and signs of increased activity), are validated elements of the bipolar spec- of Kleist’s concept of bipolar disorder as a the number and nature of symptoms re- trum. These hypotheses may be correct, combination of the two monopolar disor- quired and the minimum duration of an but we need much more genetic and ders depression and mania (Kleist, 1937, episode. A duration of under 4 days (2 days follow-up evidence to support them. 1953).This model has proved fruitful not or 1 day) and the presence of two or three We can safely assume that the only in incorporating bipolar I and bipolar instead of three or four of the seven symp- prevalence of bipolar disorders is seriously II disorders but also in differentiating toms of hypomania are now proposed and under-reported and that the burden of mania with or without mild depression have been partially validated. As with de- bipolar disorder, estimated by the World (Md/M) from bipolar I disorder (MD). pression, brief spells of hypomania (1–3 Health Organization to be much lower Mania is not identical to bipolar I disorder days) are far more common than manifesta- than that of depression, will as a conse- in terms of family history, course and tions lasting 4 days or 1 week. In order to quence have to be reassessed. suicide risk, and on the sub-threshold level improve the recognition of bipolarity, we The mood spectrum is also embedded hypomania is not the same as minor bipolar have proposed a sub-diagnostic concept in the spectrum of functional psychoses, in- disorder or cyclothymic disorder in terms of consisting of a few hypomanic symptoms cluding schizophrenia and schizoaffective family history and temperament. of brief duration associated with a lifetime and affective disorders. There is growing Both the above bipolar spectrum con- diagnosis of depression. clinical evidence that the spectrum ap- cepts are dimensional in nature, having no What we need today is an empirically proach, with its dimensional nature, offers natural categorical subgroups. Epidemiolo- validated, sensitive definition of hypoma- a real alternative to the traditional Kraepe- gical and clinical studies have demonstrated nia, which will allow early recognition of linian dichotomy of schizophrenia v.v. the continuous distribution of depressive major and minor bipolar disorders. Promis- manic-depressive insanity (Marneros, and hypomanic/manic symptoms and ing modern screening instruments for the 2006) and the unipolar–bipolar dichotomy. syndromes from normal to pathological. self-assessment of hypomanic symptoms Moreover, in agreement with clinical genetic Psychiatric symptoms in consulting popula- have now been developed such as the Mood studies (Angst & Scharfetter, 1990), modern tions have been shown to be dimensional Disorder Questionnaire (Hirschfeld et aletal,, molecular genetic studies demonstrate that (Goldberg, 2000). Moreover, in a 20-year 2000) and the Hypomania Checklist–32 there is no clear-cut distinction between follow-up, patients with type I and type II (Angst(Angst et aletal, 2005), but there is still no gold schizophrenia and bipolar affective disor- bipolar disorder were found to spend about standard for valid cut-off points for caseness der; both clinically and genetically they half the time in sub-threshold affective con- on these continuous measures: that would share many features (Craddock & Owen, ditions, and these were dimensional, invol- depend on a validated definition of hypoma- 2005).2005). ving the full range of symptom severity of nia, which is still lacking. A similar problem Diagnostic concepts of psychiatric syn- depression and hypomania (Judd et aletal,, is present in measures of temperament, dromes are purely descriptive and cannot

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constitute diseases (Kendell, 1999). The JULES ANGST,MD, Zurich University Psychiatric Hospital, Lenggstrasse 31,PO Box 1931,CH^8032 Zˇrich, proposed mood spectrum model unifies Switzerland. Email: jangst@@bli.unizh.chbli.unizh.ch categorical classification, which is essential, with a dimensional view, which is true to (First received 8 August 2006, final revision 10 September 2006, accepted 11September 2006) nature; both are needed and both are empirically testable. Goldberg, D. (2000) Plato versus Aristotle: categorical Kleist, K. (1953) Die Gliederung der neuropsychischen REFERENCES and dimensional models for common mental disorders. Erkrankungen. Monatsschrift fufur«rPsychiatrieund Psychiatrie und Comprehensive Psychiatry,, 4141, 8^13.,8^13. NeurologieNeurologie,, 125,526^554.

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