The mathematical case against unipolar mania

Recurrent unipolar mania: A comparative, cross-sectional study

INTRODUCTION

A significant number of patients experience recurrent episodes of mania without depressive episodes. Evidence from the available literature suggests that these patients differ from typical "bipolar" or "manic-depressive" patients, but results have been inconsistent. The current study aims to add to this literature by comparing the demographic, clinical and risk factor profiles of patients with recurrent mania with and without depression.

METHODS

66 patients with a diagnosis of bipolar I disorder were divided into "unipolar mania" (recurrent mania alone, MA) and "bipolar" (both mania and depression, MD) sub-groups. Comorbid diagnoses were assessed using the Mini International Neuropsychiatric Interview (MINI), and genetic and environmental risk factors were explored using the Diagnostic Interview for Genetic Studies (DIGS), Childhood Trauma Questionnaire (CTQ), and an additional questionnaire designed for the purpose of the study. Differences between the MA and MD groups in terms of demographic variables, clinical profile, comorbidities and antecedent risk factors were explored.

RESULTS

Patients with both mania and depression had higher frequencies of lifetime suicide attempts, antidepressant treatment, and catatonic symptoms. There was some evidence of an association between overcrowding in childhood and the presence of depressive episodes. No other differences in demographic, clinical or risk factor variables could be found between the two groups.

DISCUSSION

Our results are consistent with the view that unipolar mania is not a distinctive disorder, or even a distinctive subtype of bipolar disorder. However, this conclusion is provisional as it is based only on clinical and demographic data.

Is unipolar mania a distinct subtype?

BACKGROUND

Some recent reports raised the question whether unipolar mania, without severe or mild depression, really exists and whether it defines a distinct disorder. Literature on this topic is still scarce, although this was a matter of debate since several decades.

METHOD

Eighty-seven inpatients with Diagnostic and Statistical Manual of Mental Disorder, Revised Third Edition, manic episode and at least 3 major affective episodes, in 10 years of illness duration, were systematically evaluated to collect demographic and clinical information. The symptomatological evaluation was conducted by means of the Comprehensive Psychopathological Rating Scale. Clinical features, social disability, first-degree family history, and temperaments were compared between unipolar and bipolar manics.

RESULTS

Nineteen (21.8%) of 87 patients presented a course of illness characterized by recurrent unipolar manic episodes without history of major or mild depression (MAN). When this group was compared with 68 (78.2%) manic patients with a previous history of depressive episodes (BIP), we found substantial similarities in most demographic, familial, and clinical characteristics. MAN group reported more congruent psychotic symptoms and more frequent chronic course of the current episode in comparison to BIP group. In the MAN patients, we also observed a high percentage of hyperthymic temperament and a complete absence of depressive temperament. This latter difference was statistically significant. MAN patients compared with BIP ones also reported lower severity scores in social, familial, and work disability, and they showed less depressive features, hostility, and anxiety.

CONCLUSION

The numerous demographic, clinical, and psychopathological overlapping characteristics in unipolar and bipolar mania raise questions about the general nosographic utility of this categorization. Nonetheless, our data suggest a clinical and prognostic validity of keeping unipolar manic patients as a separate subgroup, in particular, as social adjustment and disability are concerned.

The structure of affective symptoms in a sample of young adults

Symptoms of bipolar disorders include depression and mania. The term "bipolar" implies states that are opposite to each other. Construing scales that define mania and depression as opposite ends of one dimension cannot account for the existence of mixed symptoms. One self-report instrument, the Internal State Scale (ISS), combines both dimensions in one measure. However, the ISS only assesses internal subjective states and does not tap other typical and more objective symptoms of (hypo-) mania. To explore the factorial structure of affective symptoms in a general population sample, we extended the Center for Epidemiologic Studies-Depression Scale (CES-D), adding items to assess manic symptoms as described in DSM-IV. The scale was completed by 2,059 young adults. The results for the original CES-D are comparable to prior studies. Factor-analysis for the extended CES-D revealed two factors in women and men: most manic symptoms loaded high on a factor "euphoria-activation," whereas the other factor included all typical dysphoric-depressive symptoms, but also included the "manic symptoms" of distractibility and irritability. Our results support a two-factor model of bipolar symptoms in the general population with irritability being more closely associated with dysphoria than euphoria. The implications and limitations of the present results are discussed.

Recurrent unipolar mania in a psychiatric hospital setting in the Fiji Islands

This study aimed to determine the rate of unipolar mania and compare its characteristics with those of other bipolar affective disorders in a psychiatric hospital in the Fiji Islands. Fifty-one patients with unipolar mania seen between January 1999 and October 2000, had their diagnosis confirmed using the Schedules for Clinical Assessment in Neuropsychiatry and the International Classification of Diseases, 10th edition. Their demographic and clinical characteristics were compared with those of 31 manic-depressive patients seen during the period under review. Unipolar mania constituted 47.2% of the bipolar affective disorders in this sample. The frequency of episodes, duration of affective illness, mean age at onset, gender distribution, marital status, employment status and race were not significantly different for the unipolar manic and manic-depressive groups (p > 0.05). Family history of major psychiatric morbidity was 9.8% for the unipolar manic patients and 22.6% for the manic-depressive group (p > 0.05). Recurrent unipolar mania may be considered a useful category based on its high rate, although its demographic and clinical characteristics do not clearly distinguish it from manic-depression.

Unipolar vs. bipolar mania: a review of 247 patients

Previous studies attempting to support unipolar mania as an entity distinct from bipolar disorder, have produced conflicting results. The present study reports on a chart review of 247 patients admitted to the University of Iowa with a history of at least one manic episode; 87 of these had apparently never experienced a depression. A subgroup of 92 patients, who met DSM III diagnostic criteria and had a history of at least two episodes of affective disorder, were also examined. There were few clinically meaningful differences between patients with unipolar mania and bipolar disorder on demographic, symptomatic, or familial variables. An earlier report that unipolar manics were more likely to be male and have a family history of unipolar depression was not confirmed. Unipolar mania is not supported as a separate entity from bipolar disorder.