Pseudobulbar affect (PBA) is a relatively common disorder of emotional expression that occurs in many neurologic disorders including amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, dementia, parkinsonian disorders, brain tumor, and traumatic brain injury. Pseudobulbar affect is a significant national health issue in the United States, occurring in greater numbers of individuals than those affected by Parkinson disease, MS, or ALS. An estimated 2 million individuals are affected in the United States.1 According to The PBA Registry Series, the prevalence of PBA symptoms in patients with specific neurologic conditions is as follows: Alzheimer disease, 29%; ALS, 45%; MS, 46%; Parkinson disease, 26%; stroke, 38%, and traumatic brain injury, 52%.2 Despite the significant prevalence of this disorder, many providers are unaware of or frequently misdiagnose PBA.
Pseudobulbar affect is characterized by sudden, frequent, uncontrollable outbursts of crying and/or laughing that may be disproportionate or inappropriate to the social context. Although patients may experience uncontrollable crying, laughing, or both, the former appears to be a more common manifestation of PBA. Crying is often described as occurring in situations that are sad or otherwise emotionally touching but that would not have produced such a striking emotional response from the patient in the past. Examples might include a sad television show, the death of a distant relative, or a show of affection by a child or grandchild. Uncontrolled laughing may occur in situations that are only mildly amusing and may have produced a chuckle under normal circumstances. The degree of the emotional response by the patient is often striking, with the crying or laughter persisting for a considerable period of time and unable to be suppressed by the patient. In addition, laughing and crying by the patient may occur in situations that are not perceived by others as being sad or funny.1
Depression vs pseudobulbar affect
The pathophysiology of PBA is incompletely understood, but symptoms are thought to result from damage to neural pathways associated with motor functioning and emotional processing. Data suggest that PBA is underrecognized by neurologists and psychiatrists; therefore, many cases are believed to go unrecognized or misdiagnosed.1 As inconsolable episodes of crying are frequent with PBA, this disorder is often misdiagnosed as depression. When misdiagnosed as depression or another personality disorder, such as bipolar disorder, inappropriate management of PBA ensues. Patients are often started on selective serotonin reuptake inhibitors (SSRIs), other antidepressants, or psychotherapy with mild to no relief of symptoms because of misdiagnosis.
To differentiate between PBA and depression, it is valuable to determine the duration of the crying episodes in order to distinguish PBA from depression. Episodes of crying with depression are often longer in duration than the episodes of pathologic crying characteristic of PBA. With depression, crying episodes commonly last weeks to months in contrast to the very brief duration of PBA episodes. Both the exaggerated emotional response and the discordance between mood and emotional display are additional characteristics of PBA that are not expected with depression.1 Patients with PBA often sob uncontrollably for seemingly no reason while verbalizing that they are not sad. They often lack the neurovegetative features of depression such as sleep disturbances and changes in appetite.