Pseudobulbar affect (PBA) is a neurological condition characterized by episodes of involuntary and uncontrollable laughing or crying unrelated to your emotions. People with PBA don’t have control over how intensely or how long they laugh or cry. Often, you won’t feel the same relief from laughter or crying that you would when you voluntarily exercise those behaviors.
Around 10% of people with MS may develop PBA. Since MS is a neurological condition in which your immune system attacks your central nervous system, some people with MS can develop PBA. If you have MS and experience uncontrollable laughter or crying, consider talking with your neurologist about these symptoms.
ALS is a motor neuron disease, meaning as motor neurons die, they can’t signal muscles, and the muscles begin to weaken. The brain eventually loses the ability to control them voluntarily. People living with ALS can have early signs, such as muscle spasms and twitches, and symptoms can be as severe as losing the ability to walk. It’s more common for people with ALS to experience uncontrollable crying — rather than laughing — when developing PBA.
PBA can occur due to TBI, a brain injury usually caused by physical head trauma. Studies show that 5–48% of people with TBI experience PBA. The wide range in prevalence of PBA in people with TBI is because PBA is not always correctly diagnosed, and some people may lack awareness of the condition. An older study suggests that when people showed symptoms of PBA and reported those symptoms to their doctor, 41% of those people were diagnosed with mood disorders such as depression, post-traumatic stress disorder (PTSD), or bipolar disorder, or their symptoms were linked to their specific medical condition rather than PBA.
Between 28 and 52% of people who’ve had a stroke may develop PBA, and people assigned female at birth may be at a higher risk. Since PBA can be difficult to diagnose, it’s essential for people who’ve had a stroke to understand their symptoms and potential side effects of medications and consider their emotions and mental health during outbursts of laughter or tears. This can help people identify unusual symptoms and explain to their doctor any unexpected behaviors.
PBA may be present in people with Alzheimer’s or Parkinson’s disease. It can affect 10–40% of people diagnosed with Alzheimer’s. Much like PBA linked with other conditions, PBA linked with Alzheimer’s is often hard to diagnose due to its similarities with certain mood disorders.
A 2019 study suggests PBA may affect 3.6 to 42.5% of people with Parkinson’s disease. However, PBA can cause symptoms that may also occur in people with conditions that resemble Parkinson’s disease, known as Parkinsonism.
If you have PBA symptoms, such as sudden and uncontrollable laughter or crying, you can consider tracking those episodes and talking with your doctor about PBA. Since PBA symptoms are often diagnosed as mood disorders, it’s essential to let your doctor know that your symptoms are not linked to your mood and emotions. You can also ask your primary doctor about working with a mental health professional and neurologist for a complete diagnosis.