Some people with Lewy body dementia (LBW) develop a symptom called pseudobulbar affect (PBA), which can lead to uncontrollable crying or laughter.

Around 20–30% of people with dementia receive a diagnosis of LBD. Its symptoms are similar to those of Alzheimer’s disease and Parkinson’s disease, making it difficult to diagnose.

This article explains why some people with LBD may cry uncontrollably and how to manage its effect on daily life.

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According to a 2019 review, around 7.7% of people with LBD can develop PBA. This involves involuntary crying or laughter that does not relate to how the individual with LBD is feeling.

PBA is not a mood disorder. It develops as a person with LBD loses emotional regulation and control of emotional expression over time. LBD may disrupt the function of brain areas linking to movement, emotions, and logical association.

The above review suggests that the cerebellum may be particularly important. This area of the brain usually plays a role in controlling emotional expression so that displays of emotion relate to the context in which a person feels them.

In people with LBD, interference with a brain network involving the cerebellum can lead to crying or laughter that far exceeds or is seemingly unrelated to the context.

What is LBD?

LBD is a neurological disease that involves irregular deposits of a protein called alpha-synuclein in the brain. These deposits — Lewy bodies — interfere with brain chemicals in ways that disrupt thinking, movement, mood, and behavior.

The symptoms of LBD are expected to worsen and usually progress from diagnosis to death within 5–8 years. However, this can vary and be between 2 and 20 years for some people.

Learn more about LBD.

The effects of PBA are distinct from crying due to sadness or depression. The crying may occur suddenly and is usually brief — lasting from a few seconds to several minutes.

This can lead to several other emotions, including:

  • embarrassment
  • distress
  • frustration
  • worry
  • confusion
  • inappropriate laughter

Episodes of PBA crying may be mild or appear more like panic attacks. A person’s facial expressions may not match the emotions they are expressing.

In addition to PBA, other symptoms of LBD include:

  • hallucinations
  • lack of inhibition
  • impaired memory
  • difficulty concentrating
  • movement symptoms
  • sleeping difficulties

Learn more about PBA.

A mildly sad or funny situation can trigger an extreme emotional reaction in people with LBD. There may also be no trigger at all.

Examples might include the following:

  • Triggers seem at odds with the reason for crying or laughing: For example, a person with PBA may cry intensely at a funny story someone tells.
  • Triggers do not match the scale of the reaction: Something a person used to find mundane could make an individual with PBA weep or laugh hysterically for minutes.
  • Triggers come from external events rather than internal mood: For example, a person with PBA may cry or laugh uncontrollably at a physician’s questions about prior crying or laughing episodes, according to a 2014 review.

LBD is progressive, and there is no treatment for the underlying cause. Maintaining quality of life with LBD involves managing symptoms. For LBD crying, the aim is to reduce how often a person experiences episodes and their severity.

The Food and Drug Administration (FDA) has only approved one direct treatment for PBA. This is a drug called Nuedexta that combines dextromethorphan and quinidine. A 2016 study of 367 participants with PBA resulting from dementia, stroke, or brain injury found that Nuedexta reduced PBA episodes of crying or laughter by 72.3% after 90 days of receiving the drug.

Some doctors also prescribe low dose antidepressants, such as selective serotonin reuptake inhibitors, including citalopram and sertraline.

Sudden and extreme crying or laughing can be isolating and distressing for people with LBD. However, caregivers and loved ones can support those experiencing PBA episodes in the following ways:

  • Making a plan: The caregiver and person with PBA can make a plan in advance on how they will handle a crying or laughing episode.
  • Seeking privacy: A caregiver can help someone with PBA find a private place when an episode starts to help them feel less exposed.
  • Being proactive: Take the person away from an overwhelming situation.
  • Providing reassurance: Tell the person that their PBA crying or laughing episodes do not cause any embarrassment.

Aside from medication, it can help to practice calming or distraction techniques when an episode starts. These might include:

  • practicing calming exercises, such as yoga, deep breathing, or meditation
  • breathing slowly until a feeling of control resumes
  • adjusting posture as soon as an episode feels like it is starting, which could help prevent a person from crying
  • distracting techniques, such as counting objects on a nearby shelf

Informing loved ones, friends, and colleagues can also help. As LBD can cause frustration or embarrassment during an episode, it can help those who experience LBD to tell people around them about the condition.

An information card can inform strangers about a person’s PBA and that they need time for the episode to pass. Individuals can print and provide a copy to help assist them in social settings.

However, as symptoms progress, people with LBD will lose daily function and may need an increasing amount of support. They may eventually require a full-time carer and help with end-of-life preparations. It is important for loved ones to come to terms with behavioral changes, maintain dignity, and respond to hallucinations in ways that reduce further tension.

People with LBD can stay as social as they are comfortable, which might also involve joining a support group such as the LBD Crew, provided by the Lewy Body Resource Center. It is also important for those providing care to look after themselves, consider respite care, and recognize when they need to take a few steps back for their own well-being.

It is advisable to ask a doctor about the best way to prepare for dementia caregiving when the individual with LBD begins to lose independent function.

Lewy body dementia (LBD) is a progressive disease that can trigger episodes of extreme, uncontrollable crying or laughter. This may be due to pseudobulbar affect (PBA), a disruption in the parts of the brain that regulate emotions. The crying or laughter might be completely out of proportion to the trigger, or there may be no trigger.

Some medications — including Nuedexta — can help reduce this symptom of LBD. It is important for caregivers and loved ones around the individual with LBD to be aware of their PBA episodes, providing reassurance and social support where necessary.