Introduction: Although present classifications (CIM, DSM) have not included the notion of a unipolar disorder to characterise the recurrence of the same type of episode, this concept conserves its pertinence for many people. Unipolar mania, in particular, is a clinical reality in our daily practice, and a predominant form of bipolarity expression. These assertions have led us to question this notion and its nosographical place: is it a subtype, distinguished by certain characteristics, or a particular category in the bipolar disorder?
Methodology: We conducted a retrospective, descriptive and comparative study on medical briefs of patients with type I bipolar disorder (DSM-IV criteria), who were interned for the first time between 1997 and 2001 in the Psychiatry "E" service of the Razi hospital of Tunis, and were followed up for at least five years. Two groups were identified: Group 1 or "unipolar mania": patients who presented at least two manic episodes without depression, and Group 2: the rest of the sample; and then were compared based on their sociodemographical profile, familial psychiatric antecedents, premorbid temperament, comorbidity and clinical and progressive characteristics.
Results: Seventy-two patients were included. The average age was 36. The sex ratio was three men to two women. The first episode was a manic episode in 56.9% of the cases. The average duration of illness progression was 11.6 years. Unipolar mania represented 65.3% of the sample. Between 1997 and 2001, 92% of bipolar patients interned were hospitalised for mania. Concerning recurrences, we observed nine times as many cases of manic episodes as depression. Depressive episodes of light to medium intensity had probably not been well assessed due to the families' tolerance. The high rates of both manic episodes and unipolar mania observed in this study were also found by other authors, showing the differences of bipolarity expression between the West and the other parts of the world, and in particular Africa. There was no significant difference concerning the sociodemographical features. We noticed similar results in the literature. The two groups were comparable in familial psychiatric past history and premorbid temperament. Substance abuse or dependence was observed in 5.6% of the patients. This rate was less than others found in the literature, due to the fact that it is considered as an offence in our country. We found twice as many cases of toxic consumption in bipolar as in unipolar manic patients. A recent Tunisian study has shown the absence of substance abuse in unipolar manic patients. This is probably because of the fact that substance abuse is more related to depressive manifestations. The sample starting age was 24.6 years and was significantly more precocious in the unipolar manic group (27.6 years versus 23 years, p=0.001). A significant difference in both groups was found concerning the first episode season: two extremities were observed: "summer-autumn" in Group 1 (63.6% G1 versus 29.4% G2) and "winter-spring" in Group 2 (73.6% G2 versus 36.4% G1), p=0.03. The seasonal influence on mood disorders is dealt with by other authors. Unipolar manic patients presented less affective recurrences than the rest of the group (0.37 versus 0.49 on average per year), p=0.056.
Conclusion: Unipolar mania is still considered as a clinical variety of bipolar disorder, which is distinguished by certain features. It is a debated notion because it is based on retrospective studies that may be insufficient, although it appears as a clinical evidence and a predominant progressive variety of bipolar disorder in Tunisia.