Bipolar disorder isn’t one single condition — it’s a spectrum of related mood disorders that share cycles between elevated and depressed states, but differ in intensity and pattern. Knowing the type matters, because it shapes treatment.
The common thread
All types of bipolar involve shifts between two poles: episodes of elevated or energised mood (mania or hypomania) and episodes of depression. What differs is how high the “highs” go and how the pattern plays out.
Bipolar I
Defined by at least one episode of mania — a distinct period of abnormally elevated, expansive or irritable mood with high energy, lasting at least a week (or requiring hospitalisation). Mania can involve reduced need for sleep, racing thoughts, grandiosity, rapid speech, and risky behaviour, and in severe cases, psychosis. Depressive episodes usually occur too, though they aren’t required for the diagnosis.
Bipolar II
Defined by at least one episode of hypomania — a milder form of elevated mood that doesn’t cause the severe impairment of full mania — together with episodes of major depression. Bipolar II is often missed, because people typically seek help during the depression and may not recognise the hypomanic periods as a problem. It is not a “milder” illness overall; the depressions can be severe and prolonged.
Cyclothymia
A chronic, fluctuating condition with numerous periods of hypomanic and depressive symptoms that don’t quite meet the threshold for full episodes, lasting two years or more. It can be distressing and can sometimes develop into bipolar I or II.
Why the distinction matters
Bipolar depression is treated differently from unipolar depression — some standard antidepressants used alone can be unhelpful in bipolar — which is why an accurate diagnosis is so important. If you’ve been treated for depression without lasting benefit, it’s worth exploring whether elevated periods have been missed. Try our bipolar self-check, read about our bipolar care, or book an appointment with a referral.
This article is general information, not medical advice. In a crisis, call Lifeline on 13 11 14 or 000.