In addition to making a diagnosis of a particular disorder, a clinician can also say how it is different from other conditions that may have similar symptoms. This is known as a differential diagnosis. This information can help a clinician narrow down which treatments may work best for the patient. It may also be used to provide information about a person's anticipated course of the disorder and their prognosis (outcome).
Clinicians may use the following differential diagnoses to describe Bipolar and Related Disorders:
With Anxious Distress - this is when a person feels keyed up/tense, is unusually restless, or has a feeling or fear that something awful may happen or they may lose control. A clinician will typically label the disorder as mild to severe based on the number of anxiety symptoms the person experiences.
With mixed features - These are behaviors that are typically observed by others and represent a change from the person's usual behavior. A hypomanic or manic episode with mixed features would include symptoms that are typically found in a depressive episode (depressed mood, lack of interest or pleasure from activities, fatigue or loss of energy, etc.). A depressive episode with mixed features would include hypomanic or manic symptoms, such as elevated mood, inflated self-esteem, increased energy, risky behavior, etcetera.
With rapid cycling - There have been at least four mood episodes in the previous 12-months that met the full criteria for mania, hypomania or major depressive episodes. This specifier can be used with bipolar I and II diagnoses.
With atypical features - this is when symptoms occur with mood reactivity. For example, the person's mood brightens when good things happen, when they gain weight or have an increase in appetite, sleep more than usual, or have heavy almost paralyzing feeling in their arms and legs. These features should not occur in the same episode with melancholic or catatonic features.
With psychotic features - this is used when delusions and/or hallucinations are experienced. When the delusions and/or hallucinations are consistent with typical manic feelings such as inflated sense of self-esteem, being invulnerable, or feeling suspicious or paranoid, they are said to be mood-congruent. When they do not follow typical manic feelings, but are instead the opposite or a mixture of the two, they are known as mood-incongruent.
With peripartum onset - this is used if the onset of hypomania, mania or major depressive disorder occurs during pregnancy or in the 4 weeks following childbirth. This is just when the symptoms first appear, but they may last longer than the noted four weeks. Because 50% of 'postpartum' episodes begin during pregnancy, this category is now called peripartum rather than postpartum.
With catatonia - In this case, a person displays one or many unusual movements and mannerisms, including:
- stupor (periods during which they do not move or actively relate to the environment)
- excessive movement
- catalepsy (passively being put into postures and holding them for periods of time, sometimes against gravity)
- waxy flexibility (resistance to positioning)
- mutism (no verbal response)
- negativism (opposition or no response to instructions)
- posturing (spontaneous and active maintenance of a posture held against gravity)
- mannerism (odd caricature of normal actions)
- stereotypy (repeating behaviors over and over without a goal)
- prominent grimacing; echolalia (mimicking someone else's speech)
- echopraxia (mimicking another's movements).
For example, a person sitting on a park bench who seems unable to stop imitating gestures and words of passers-by might be suffering from a bipolar disorder with catatonic features.
With seasonal pattern - this occurs when a person experiences mood symptoms at a particular time of year, and then feels a lifting of symptoms at other times of the year on a regular basis for the past two years.