BACKGROUND: To compare individuals in primary care (PC) who screen positive for bipolar depression to those who screened positive for unipolar depression on mental health care ouctomes, PC service utilization, medical comorbidities, suicidal ideation, health-related quality of life (HRQoL) and psychosocial functioning.METHODS: In this cross-sectional study, participants (N=1197) answered self-reported measures of depressive symptoms (Center for epidemiologic studies depression scale), HRQoL (World Health Organization Quality of Life instrument-Abbreviated version), medical comorbidity (functional comorbidity index) and functioning (Functional Assessment Short test). Participants were partitioned into 'bipolar' and 'unipolar' depression groups based on a predefined cutoff on the Brazilian mood disorder questionnaire.RESULTS: The prevalence of bipolar depression was in PC was 4.6% (95% CI: 3.4-5.8). Participants with bipolar depression were more likely to endorse suicidal ideation, present with more medical comorbidities, report a worse physical HRQoL and have a higher rate of PC services utilization as compared to participants who screened positive for unipolar depression. Only six (10.9%) participants were recognized by the general practitioner as having a diagnosis of bipolar depression.LIMITATIONS: The cross-sectional design prevents firm causal inferences from being drawn. A positive screen for BD does not substantiate the actual diagnosis. Co-morbid mental disorders were not accessed.CONCLUSIONS: Bipolar depression is common and under-recognized in Brazilian PC services. A positive screen for bipolar depression was associated with worse clinical outcomes and greater PC service utilization.