Pseudobulbar affect (PBA), emotional lability, labile affect, or emotional incontinence refers to a neurologic disorder characterized by involuntary crying or uncontrollable episodes of crying and/or laughing, or other emotional displays. PBA occurs secondary to neurologic disease or brain injury. Patients may find themselves crying uncontrollably at something that is only moderately sad, being unable to stop themselves for several minutes. Episodes may also be mood-incongruent: a patient might laugh uncontrollably when angry or frustrated, for example.
The cardinal feature of the disorder is a pathologically lowered threshold for exhibiting the behavioral response of laughter, crying, or both. An affected individual exhibits episodes of laughter and/or crying without an apparent motivating stimulus or in response to stimuli that would not have elicited such an emotional response before the onset of their underlying neurologic disorder. In some patients, the emotional response is exaggerated in intensity but is provoked by a stimulus with an emotional valence congruent with the character of the emotional display. For example, a sad stimulus provokes a pathologically exaggerated weeping response instead of a sigh, which the patient normally would have exhibited in that particular situation.
However, in some other patients, the character of the emotional display can be incongruent with, and even contradictory to, the emotional valence of the provoking stimulus or may be incited by a stimulus with no clear valence. For example, a patient may laugh in response to sad news or cry in response to stimuli with no emotional undertone, or, once provoked, the episodes may switch from laughing to crying or vice versa.
The symptoms of PBA can be severe, with persistent and unremitting episodes. Characteristics include:
the onset can be sudden and unpredictable, and has been described by some patients as coming on like a seizure;
the outbursts have a typical duration of a few seconds to several minutes; and,
the outbursts may happen several times a day.