<p>Differentiating between bipolar depression and unipolar depression at the first presentation of a depressive episode is critical for accurate diagnosis and effective treatment. While both disorders present similar depressive symptoms, nearly 50% of bipolar disorder cases first manifest with depressive episodes, leading to continual misdiagnosis as unipolar depression. This narrative review explores the clinical variances between the two disorders, emphasizing crucial aspects such as age of onset, symptom patterns, family history, comorbidities, and treatment responses. Outcomes recommend that bipolar depression is associated with atypical features, earlier onset, more severe symptoms, and higher rates of psychiatric and medical comorbidities. Notwithstanding communal diagnostic criteria, clinicians can improve diagnostic precision through comprehensive patient history, symptom assessment, and the use of screening tools. The review underscores the necessity for additional research to determine precise diagnostic criteria that can effectively distinguish bipolar depression from unipolar depression during the initial depressive episode.</p>