Clinical features of differential diagnosis between unipolar and bipolar depression in a drug-free sample of young adults.

INTRODUCTION

Subjects with bipolar disorder suffering of a depressive episode are frequently misdiagnosed as unipolar depression, being important studies assessing the differential diagnosis between bipolar and unipolar depression.

OBJECTIVE

To assess the sociodemographic and clinical features of drug-free young adults in a depressive episode of bipolar or unipolar disorder in order to identify factors that may differentiate these psychiatric conditions.

METHODS

This is a cross-sectional study with 241 young adults aged between 18 and 29 years who were evaluated using the Structured Clinical Interview for DSM-IV (SCID). The sample comprised patients with BD (n = 89) and major depressive disorder (n = 152), experiencing a depressive episode and not using psychoactive drugs or illicit psychoactive substances.

RESULTS

The characteristics associated with bipolar depression were being male (p < 0.001), with a family history of BD (p = 0.013), a higher frequency of childhood traumatic experiences (p = 0.001), younger age of onset of mood disorder (p = 0.004), many previous depressive episodes (p = 0.027), greater severity of depressive symptoms (p < 0.001) and day/night reversal (p = 0.013). Those with unipolar depression showed a higher frequency of biological rhythm disturbances (p < 0.001), and diurnal preference (p = 0.028).

LIMITATIONS

The sample has not included subjects with severe suicide risk, a possible important marker in differentiate unipolar from bipolar depression.

CONCLUSION

Some clinical aspects may contribute to an early differential diagnosis of both bipolar and unipolar depression even in the initial stages of the disease.