Bipolar disorder, previously called manic-depressive illness, involves extreme mood swings between manic highs and depressive lows. Diagnosis is clinical no single blood test or brain scan confirms it. Instead, psychiatrists or trained clinicians follow a structured process based on DSM-5 criteria from the American Psychiatric Association.

1. Initial Screening: It starts with a detailed interview. The doctor asks about mood episodes: Have you had periods of elevated energy, reduced need for sleep, racing thoughts, or risky behavior lasting at least 4–7 days (mania) or milder but longer (hypomania)? Conversely, have you experienced prolonged sadness, hopelessness, or loss of interest for 2+ weeks (depression)? Family history is key bipolar often runs in families.
2. Mood Tracking Tools: Patients may complete standardized questionnaires like the Mood Disorder Questionnaire (MDQ) or Young Mania Rating Scale (YMRS). These screen for symptoms but aren’t diagnostic alone.
3. Physical Exam & Labs: To rule out mimics (e.g., thyroid issues, substance abuse, or neurological conditions), doctors order blood tests (CBC, thyroid panel, drug screen) and sometimes EEG or MRI.
4. Longitudinal Observation: Bipolar requires evidence of at least one manic/hypomanic episode plus depression. Clinicians may track moods via journals or apps over weeks/months.
5. Differential Diagnosis: They exclude schizophrenia, ADHD, borderline personality, or medication side effects.

Diagnosis typically takes multiple visits. Early detection improves outcomes with therapy, meds (e.g., lithium, antipsychotics), and lifestyle changes. If suspecting bipolar, consult a psychiatrist self-diagnosis is unreliable.