For any mood episode to count toward a diagnosis of bipolar disorder, the mood episode can’t be better explained by schizoaffective disorder, schizophrenia, schizophreniform disorder, delusional disorder, other specific or unspecified schizophrenia spectrum disorders, or other psychotic disorders. All these conditions have at least some period of psychosis that’s not part of a mood episode. The point is to clarify that a bipolar diagnosis can’t be decided if symptoms include disordered thinking and reality testing that aren’t part of a mood episode. (For more about psychosis, see “Presence or absence of psychosis,” later in this chapter.)

      Distinguishing Types of Bipolar Disorder

      Bipolar disorder wears many masks. It can be happy, sad, fearful, confident, sexy, or furious. It can seduce strangers, intimidate bank tellers, throw extravagant parties, and steal your joy late into the night. However, based on research, psychiatrists have managed to bring order to the disorder by grouping the many manifestations of bipolar into categories that include bipolar I, bipolar II, and cyclothymic disorder. In the following sections, we offer guidance for distinguishing among the many different types of bipolar disorder.

      To earn the bipolar I label, you must experience at least one manic episode sometime during your life (see “Manic episode,” earlier in this chapter). A major depressive episode isn’t required for the bipolar I diagnosis, although many people with bipolar I have experienced one or more major depressive episodes at some point in their lives. In fact, depression is actually the phase of bipolar that causes the most problems for people with bipolar.

      

Bipolar I requires a manic episode. If you’ve never had a manic episode, you don’t have bipolar I. If you’ve only ever had a hypomanic episode, you don’t have bipolar I.

      Bipolar II is characterized by one or more major depressive episodes with at least one hypomanic episode sometime during the person’s life. The major depressive episode must last at least two weeks, and the hypomania must last at least four days. (For more about what qualifies as hypomania, check out the earlier section “Hypomanic episode.”)

      

Bipolar II requires at least one major depressive episode and one hypomanic episode. If you’ve ever had a manic episode that can’t be attributed to some other cause, then you have bipolar I, not bipolar II.

      Cyclothymic disorder involves multiple episodes of hypomania and depressive symptoms that don’t meet the criteria for a manic episode or a major depressive episode in intensity or duration. Your symptoms must last for at least two years (or one year in children or adolescents) without more than two months of a stable, or euthymic, mood during that time to qualify for a cyclothymic disorder diagnosis.

      

Some people with cyclothymic disorder eventually experience a full-blown manic or depressive episode, leading to an additional diagnosis of bipolar I or II. Medical supervision is important so that treatment planning can change if symptoms change.

      The substance/medication-induced bipolar disorder diagnosis applies when someone presents with all the symptoms of bipolar disorder (elevated, expansive, or irritable mood with or without depression), but only in the context of acute substance intoxication or withdrawal or medication effects. When this diagnostic category is used correctly, the mood disorder doesn’t predate the introduction of the substance or persist long after the substance effects or withdrawal is over.

      When a person’s mania or hypomania can be traced to another medical condition, such as hyperthyroidism (overactive thyroid), based on medical history, physical examination, or lab results, the person may receive a diagnosis of bipolar and related disorder due to another medical condition, and the doctor will identify that other medical condition.

      Introduced in DSM-5, this diagnosis enables doctors to diagnose bipolar disorder when symptoms characteristic of bipolar disorder significantly impair normal function or cause considerable distress, but don’t quite meet the full diagnostic criteria for the other bipolar diagnostic classes. Here are some examples:

      ✔ Major depression with short-duration hypomanic episodes: An individual has experienced one or more major depressive episodes and two or more hypomanic episodes, but the hypomanic episodes have lasted for only a couple days (not the full four consecutive days required). In addition, the hypomanic episodes don’t overlap with the major depressive episodes, which would call for a diagnosis of major depression with mixed features.

      ✔ Major depression with hypomania that fails to meet the criteria for a hypomanic episode: An individual has experienced one or more major depressive episodes along with periods of hypomania that fall short of the symptoms required for a hypomanic episode. For example, the person may have an elevated or expansive mood for four consecutive days, but she has only two of the three other symptoms required to qualify as having had a hypomanic episode.

      ✔ Hypomanic episode without a major depressive or manic episode: This designation enables doctors to diagnose bipolar disorder in the absence of a full-blown major depressive episode (which would result in a diagnosis of bipolar II) or a manic episode (which would result in a diagnosis of bipolar I).

      ✔ Short-duration cyclothymia: An individual has experienced multiple periods of depression and hypomania that don’t meet the criteria for major depressive episode or hypomanic episode in the course of fewer than 24 months (or fewer than 12 months in children or adolescents).

      

All bipolar diagnoses require that the symptoms cause significant clinical distress or functional impairment. Although doctors certainly want to diagnose and treat people with bipolar disorder and other conditions covered in the DSM, they don’t want to overdiagnose and overmedicate. Treatment is provided only when it begins to disrupt a person’s ability to function normally and enjoy life’s pleasures.

      The unspecified bipolar disorder designation is used to diagnose individuals who present with symptoms characteristic of bipolar disorder that cause clinically significant distress or functional impairment but don’t fully meet the diagnostic criteria for the other bipolar disorder diagnostic categories. This diagnosis is used instead of other specified bipolar and related disorder when a doctor, for whatever reason, doesn’t want to go into detail about why the criteria for a specific bipolar diagnosis hasn’t been met; for example, in emergency room settings by doctors who need to diagnose and treat the symptoms immediately and may not have the time or sufficient details to make a more specific diagnosis.