A Mixed 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 mixed manic and depressive 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 I Disorder) and the general medical condition is recorded on Axis III (e.g., myocardial infarction).
A Substance-Induced Mood Disorder is distinguished from a Mixed 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 Mixed Episode may be precipitated by use of a drug of abuse (e.g., mixed manic and depressive symptoms that occur only in the context of intoxication with cocaine would be diagnosed as Cocaine-Induced Mood Disorder, With Mixed Features, With Onset During Intoxication). Symptoms like those seen in a Mixed 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 Mixed Features; Electroconvulsive Therapy-Induced Mood Disorder, With Mixed Features). However, clinical judgment is essential to determine whether the treatment is truly causal or whether a primary Mixed Episode happened to have its onset while the person was receiving the treatment.
Major Depressive Episodes with prominent irritable mood and Manic Episodes with prominent irritable mood may be difficult to distinguish from Mixed Episodes. This determination requires a careful clinical evaluation of the simultaneous presence of symptoms that are characteristic of both a full Manic Episode and a full Major Depressive Episode (except for duration).
Attention-Deficit/Hyperactivity Disorder and a Mixed Episode are both characterized by excessive activity, impulsive behavior, poor judgment, and denial of problems. Attention-Deficit/Hyperactivity Disorder is distinguished from a Mixed 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 or psychotic features. Children with Attention-Deficit/Hyperactivity Disorder also sometimes show depressive symptoms such as low self-esteem and frustration tolerance. If criteria are met for both, Attention-Deficit/Hyperactivity Disorder may be diagnosed in addition to the Mood Disorder.