Pseudobulbar Affect

Crying young woman
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If you start breaking out into tears with little or no provocation, people may assume you’re depressed. If you also laugh with little or no cause, maybe people will question if you’re bipolar.

Pseudobulbar affect (PBA) is another potential explanation. Unlike bipolar disorder or depression, PBA usually results from damage to the brain, whether by stroke, multiple sclerosis, or a neurodegenerative illness like amyotrophic lateral sclerosis.

People with PBA may find themselves laughing or crying in socially inappropriate situations. Sometimes they may laugh or cry for no reason whatsoever, but often it’s simply out of proportion to the situation. For example, I once knew someone who started sobbing uncontrollably after passing a homeless man in the street. While homelessness is a major problem, the reaction was unusual.

Such loss of emotional control can cause significant embarrassment. For example, someone with PBA may burst out laughing during a funeral.

What Causes PBA?

Sobbing and laughing both involve a characteristic breathing pattern. In fact, if you don’t know the immediate context or see whether someone is smiling or frowning, sometimes laughter and crying sound surprisingly alike.

The associated neuronal centers for breathing are in the brainstem, near where the pons meets the medulla. This area looks a bit like a bulb—hence the “bulbar” part of the name.

These regions are also involved with other respiratory variations such as hiccupping, coughing, sneezing and yawning. To some degree, they are under the control of brain structures higher up in the skull, such as the frontal lobes.

The usual explanation for pseudobulbar affect is that the communication between those higher regions of the brain that normally regulate our emotions are disconnected somehow from those critical brainstem regions.

This may be due to any one of a number of different causes, such as a small stroke or multiple sclerosis (MS) lesion. Up to ten percent of people with MS may experience PBA.

The most commonly reported cause of PBA, however, is amyotrophic lateral sclerosis, sometimes called Lou Gehrig’s disease. While ALS doesn’t cause a directly visible lesion like stroke or MS, it does often involve wasting of brain areas involved with emotional control.

How Can PBA be Diagnosed?

The first step in treating pathological laughing and crying is identifying the underlying cause. Ultimately, PBA is more of a symptom than a disease in its own right. It would be a shame to focus just on treating PBA and miss a chance to treat underlying MS, for example.

Beyond just listening to someone’s story to diagnose PBA, additional procedures include a neurological examination to look for other signs of neurological damage, and likely a magnetic resonance imaging (MRI) scan to look for lesions in the brain that could cause such a disorder.

What Treatment is Available for PBA?  

The most widely accepted medication to treat PBA is a combination of dextromethorphan and quinidine. Such a combination was found to reduce frequency and severity of uncontrollable laughter or crying compared with either drug alone.

Side effects included nausea, dizziness, and gastrointestinal distress. Such side effects were found to be lessened with the doses now recommended for use. That dose usually starts at 20 mg/10 mg daily, then is increased to twice a day after about a week or so.

The mechanism of dextromethorphan in treating PBA is unclear. The quinidine is thought to reduce the metabolism of dextromethorphan, which would otherwise be rapidly metabolized from the patient’s system.

Other medications sometimes used to treat PBA include amitriptyline and fluvoxamine, but neither have been shown to be effective in controlled studies.


Galvez-Jimenez, N.  Symptom-based management of amyotrophic lateral sclerosis. In Up-To-Date. Section Editors Shefner JM, Targoff IN, Morrison RS. Updated May 20, 2015, Accessed June 28, 2015. 

Olney NT, Goodkind MS, Lomen-Hoerth C, et al. Behaviour, physiology and experience of pathological laughing and crying in amyotrophic lateral sclerosis. Brain : a journal of neurology 2011;134:3458-3469.

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