Is unipolar mania a distinct subtype?

Abstract 

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.