A Hypomanic Episode must be distinguished from a Mood Disorder Due to a General Medical Condition. The diagnosis is Mood Disorder Due to a General Medical Condition if the mood disturbance is judged to be the direct physiological consequence of a specific general medical condition (e.g., multiple sclerosis, brain tumor, Cushing’s syndrome). This determination is based on the history, laboratory findings, or physical examination. If it is judged that the hypomanic symptoms are not the direct physiological consequence of the general medical condition, then the primary Mood Disorder is recorded on Axis I (e.g., Bipolar II Disorder) and the general medical condition is recorded on Axis III (e.g., myocardial infarction).
A Substance-Induced Mood Disorder is distinguished from a Hypomanic Episode by the fact that a substance (e.g., a drug of abuse, a medication, or exposure to a toxin) is judged to be etiologically related to the mood disturbance. Symptoms like those seen in a Hypomanic Episode may be precipitated by a drug of abuse (e.g., hypomanic symptoms that occur only in the context of intoxication with cocaine would be diagnosed as Cocaine-Induced Mood Disorder, With Manic Features, With Onset During Intoxication). Symptoms like those seen in a Hypomanic Episode may also be precipitated by antidepressant treatment such as medication, electroconvulsive therapy, or light therapy. Such episodes are also diagnosed as Substance-Induced Mood Disorders (e.g., Amitriptyline-Induced Mood Disorder, With Manic Features; Electroconvulsive Therapy-Induced Mood Disorder, With Manic Features). However, clinical judgment is essential to determine whether the treatment is truly causal or whether a primary Hypomanic Episode happened to have its onset while the person was receiving the treatment.
Manic Episodes should be distinguished from Hypomanic Episodes. Although Manic Episodes and Hypomanic Episodes have identical lists of characteristic symptoms, the mood disturbance in Hypomanic Episodes is not sufficiently severe to cause marked impairment in social or occupational functioning or to require hospitalization. Some Hypomanic Episodes may evolve into full Manic Episodes.
Attention-Deficit/Hyperactivity Disorder and a Hypomanic Episode are both characterized by excessive activity, impulsive behavior, poor judgment, and denial of problems. Attention-Deficit/Hyperactivity Disorder is distinguished from a Hypomanic Episode by its characteristic early onset (i.e., before age 7 years), chronic rather than episodic course, lack of relatively clear onsets and offsets, and the absence of abnormally expansive or elevated mood.
A Hypomanic Episode must be distinguished from euthymia, particularly in individuals who have been chronically depressed and are unaccustomed to the experience of a nondepressed mood state.
