Bipolar 1

The only requirement for a bipolar 1 diagnosis is a single episode of mania. (For more on mania, see this post). This is one of the hardest things for people to understand about bipolar 1: A single episode of mania is enough for a bipolar 1 diagnosis. It could have been 10 years ago and only happened once, you still have bipolar. 

Although technically depressive episodes are not required for a diagnosis of bipolar 1, they are very common. 

Bipolar 2

A diagnosis of bipolar 2 requires distinct episodes of hypomania (even a single episode of mania is considered bipolar 1) and depression. As with bipolar 1, a single hypomanic episode and a single depressive episode (even if they were years ago) are enough to have a diagnosis of bipolar 2. 

Although it’s not always the case, people with bipolar 2 often have longer and more frequent depressive episodes when compared to individuals with bipolar 1 disorder (see pages 135-136 of the DSM 5). 

Cyclothymic

Cyclothymic is a more complicated diagnosis. In essence, cyclothymia is a disorder in which there are periods of time where individuals experience symptoms of hypomania (but never enough symptoms to have been hypomania) and periods of depression (but never enough symptoms to have met the criteria for major depressive disorder). These periods must be present for at least half of the time in a 2 year time frame (or 1 year for children/adolescents) and there have not been periods longer than 2 months without symptoms. 

	Bipolar 1	Bipolar 2	Cyclothymic
Mania	Present	Never present	Never present
Hypomania	Can be present	Present	Never present
Depression	Can be present	Present	Never Present

Additional Resources

What are Bipolar Disorders? from the American Psychiatric Association

Why is there a type 1 and type 2 in bipolar disorder? from the Inside Bipolar Podcast

Bipolar Disorder from NAMI: National Alliance on Mental Illness