What is Pseudobulbar Affect?
Pseudobulbar affect (PBA) is a condition that causes excessive crying or laughing. This could mean crying or laughing at an inappropriate time, or with an intensity that doesn’t match the actual emotion that someone is experiencing. It is associated with a variety of neurological conditions, including Amyotrophic Lateral Sclerosis (ALS), Parkinson’s Disease, stroke, and traumatic brain injuries.
For example, someone with PBA may:
- Laugh at something that is sad, or cry about something that is funny.
- Laugh or cry very intensely or for an extended period of time in response to a trigger they only find a little bit funny or sad.
- Laugh or cry at random times, unprompted.
These episodes may last up to several minutes. People experiencing PBA are unable to control these reactions, although there are some treatments that can help alleviate symptoms.
What Causes Pseudobulbar Affect?
While inappropriate laughing or crying may give the outward appearance of a mental health or cognitive issue, it is better understood as a problem with how the brain regulates the outward expression of emotions. PBA can often be misdiagnosed as depression, particularly when it is associated with episodes of crying. However, while the effects of the condition can contribute to emotional distress or depression, they can also arise in situations where someone is not experiencing these emotions. Unlike depression, which causes persistent sadness, episodes of PBA-related crying or laughing generally subside after a few minutes.
The exact cause of PBA is not known, but researchers believe it may be related to issues in the areas of the brain’s frontal lobe that regulate facial movement and emotional expression. While estimates vary, a 2022 meta-analysis found that about 38% of people with ALS experience the effects of PBA to some degree.
Pseudobulbar Affect in ALS
ALS is a disease of the motor neurons in the brain—the upper motor neurons—and the motor neurons that connect the spinal cord to the muscles in the body—the lower motor neurons. While scientists do not totally understand why some people with ALS experience PBA and others do not, it appears that people with greater upper motor neuron involvement are more likely to develop the condition.
In particular, studies have shown that people with bulbar-onset ALS—those whose first ALS symptoms manifest in the head and neck—may be at a higher risk for developing PBA. However, people with limb-onset ALS may still experience the condition.
Are there Treatments for Pseudobulbar Affect?
There are several medications that are used to treat PBA as a symptom of ALS and other diseases. While none of these treatments can completely stop PBA, researchers have found that they can be effective at reducing the frequency and intensity of symptoms. They include:
- Nuedexta: Nuedexta is currently the only FDA-approved drug for treating PBA, having received approval in 2010. It is a combination therapy of dextromethorphan, the active ingredient in common cough syrups like Robitussin, and quinidine, a medication used for treating irregular heartbeats. In a 12-week, placebo-controlled clinical trial in ALS and multiple sclerosis patients, the treatment was observed to reduce daily PBA episodes by around 47%.
- Antidepressants: While PBA is a wholly separate condition from clinical depression, researchers have found some evidence that certain antidepressant medications may be effective in treating PBA symptoms. While these drugs are not FDA-approved for PBA specifically, they are often prescribed off-label by clinicians. Antidepressants used for treating PBA generally fall into two broad categories:
- Selective serotonin reuptake inhibitors (SSRIs): SSRIs are some of the most widely prescribed medications for treating depression. Common SSRIs include Zoloft, Celexa, Lexapro, and Prozac. While there is limited research demonstrating their efficacy in treating PBA, scientists believe they may help alleviate symptoms by increasing the amount of serotonin, a neurotransmitter that helps regulate emotions, in the brain.
- Tricyclic antidepressants: These drugs are an older class of antidepressants that are currently prescribed more often as a second-line treatment for mood disorders. Like SSRIs, some small studies have shown they may have some efficacy in treating PBA symptoms at low doses.
Additionally, an occupational therapist may work with people experiencing PBA to help manage their symptoms as part of their multidisciplinary ALS care team. If you have ALS and are experiencing PBA, you should talk to your medical team about your symptoms and discuss potential options.
While there are currently no treatments that can slow or stop most types of ALS, the ALS Therapy Development Institute (ALS TDI) is working to change that. To learn more about ALS TDI and our research to end ALS, click here.
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