Pseudobulbar affect (PBA)—a condition that causes excessive and uncontrollable crying or laughing unrelated to either sadness or happiness—can occur with many neurologic conditions, including Alzheimer's disease and dementia, amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, stroke, and traumatic brain injury.
People may develop PBA when parts of the brain and brain stem that control movement have been damaged on both sides of their brains. The underlying mechanism isn't completely understood, but it may be that circuits that involve the cerebellum disrupt the coordination of emotion. Researchers continue to explore causes and treatment. To date, they don't know why some people experience PBA and others do not.
The condition may occur early or late in the underlying disease's course and is sometimes misdiagnosed as depression or bipolar disorder. (Having both depression and PBA also is common, but people with PBA usually experience shorter bouts of crying or laughing.)
While not life-threatening, PBA can make people anxious, embarrassed, or withdrawn if they fear having an outburst in social situations. Having PBA doesn't mean the underlying neurologic condition is progressing or that other symptoms will appear.
A hallmark of the disorder is a disconnect between how the person is feeling and how the person responds to that feeling (for example, feeling happy but crying or feeling sad but laughing). Other signs include an inability to control the duration or severity of crying/laughing and a lack of relief after an outburst. The condition is not related to medication or other psychiatric or neurologic disorders. PBA outbursts are not constant, and in some people they happen only occasionally.
The condition can be baffling to witness, but it is usually more disturbing to the person experiencing it than to onlookers. In some cases, people with PBA are not particularly affected and may not need or seek treatment.
The first line of treatment is usually an antidepressant. If that doesn't help, neurologists may prescribe Nuedexta, a drug approved by the U.S. Food and Drug Administration that combines dextromethorphan hydrobromide and quinidine sulfate. It may reduce the frequency and severity of episodes. Talk therapy can be useful for co-occurring depression, but it cannot treat or control PBA.
Dr. Shefner is a neurologist at the Gregory W. Fulton ALS & Neuromuscular Disease Center and professor of neurology at Barrow Neurological Institute in Phoenix.
