Pseudobulbar affect: uncontrollable laughing and crying

Pseudobulbar affect describes sudden episodes of crying, laughing or both that are out of proportion to the situation or have no obvious trigger. The key feature is a gap between what a person shows and what they feel. Someone may sob without being sad, or laugh without finding anything funny.

The MS Trust explains that the problem lies in how emotions are expressed, rather than in the emotions themselves. The Stroke Association likewise describes how damage to the part of the brain that controls emotions can change how a person experiences and expresses them.

Because the condition has many names, you may meet the terms emotional lability, emotionalism, emotional incontinence or pathological laughing and crying. They all point to the same pattern.

Sometimes an episode starts in response to something mildly sad or funny, but the reaction is far stronger and lasts longer than expected. Sometimes it arrives with no trigger at all. The MS Trust notes that it may be hard or impossible to stop, and that some people also have bouts of excessive anger or frustration.

A published review of the condition adds that crying is more common than laughter, and that even talking about the problem can set off a reaction. Episodes typically last for minutes rather than hours.

The social effects can be larger than the episodes themselves. Embarrassment, fear of the next outburst and avoiding company are common. The MS Trust says this can strain relationships if a person feels they are embarrassing family and friends.

The exact cause is unclear. The MS Trust says it is thought to arise from damage to areas of the brain that help control emotion, together with changes in how chemical messengers carry signals between nerve cells. Serotonin, dopamine, glutamate and noradrenaline are all thought to play a part.

The cerebellum, at the back of the brain, may be especially important in keeping emotional reactions in proportion to the situation. A review in Therapeutics and Clinical Risk Management describes PBA as a kind of disinhibition, where the usual braking system on emotional expression is weakened.

Common underlying conditions include the following.

• Stroke, where the Stroke Association says damage can affect how emotions are experienced and expressed.

• Multiple sclerosis, particularly when lesions affect emotion-related brain areas.

• Motor neurone disease (amyotrophic lateral sclerosis).

• Parkinson's disease and related movement disorders.

• Traumatic brain injury.

• Alzheimer's disease and other dementias, and brain tumours.

Because PBA often involves crying, it can be mistaken for depression, and the reverse also happens. Living with a serious neurological condition can bring low mood anyway, so both may be present.

The MS Trust gives some pointers for telling them apart. Depression typically lasts longer than PBA outbursts, which usually last for several minutes. PBA is not associated with common features of depression such as sleep problems or loss of appetite. The review in Therapeutics and Clinical Risk Management says depression tends to last weeks to months, and that PBA features a mismatch between mood and emotional display.

Both sources stress that the conditions can coexist, with the review quoting figures of roughly 30% to 35% of people with PBA also being depressed. If depression is suspected, it should be assessed and treated on its own terms. A full review of mood matters, because the right label determines the right treatment.

There is no blood test or scan for PBA. In practice a clinician, often a neurologist or a doctor in a stroke or MS service, recognises it from the story, usually with input from family members who see the episodes. They will check that the behaviour is a change from the person's usual responses and not better explained by another condition or a medicine.

The MS Trust describes two sets of criteria used by researchers. One looks for emotional responses that do not fit the situation, are not closely linked to feelings, cannot be controlled, and do not bring relief. The other emphasises change from a person's normal pattern, distress or social impairment, and exclusion of other causes.

Questionnaires such as the Center for Neurologic Study Lability Scale, with seven questions, can help. Writing down when episodes happen and how long they last gives your clinician useful detail.

The aim is to reduce how often and how severe episodes are. The MS Trust says the mainstay has been off-label use of antidepressants, meaning prescribing them for a purpose beyond their licence. Both tricyclic types such as amitriptyline and selective serotonin reuptake inhibitors such as fluoxetine, citalopram and sertraline are used.

According to the MS Trust, the doses tend to be lower than those used for depression, and the effect can often be seen quite quickly, typically in less than a week. It also notes that the NICE multiple sclerosis guideline suggests trying amitriptyline for emotional lability in people with MS. Any decision to start a medicine rests with your doctor, who will weigh side effects and other medicines you take.

A combination of dextromethorphan and quinidine is licensed for PBA in the United States and was approved in Europe in 2013, but the MS Trust says it was never marketed in the EU and the authorisation was withdrawn for commercial reasons, not safety. It has never been available in the UK.

Understanding that PBA is physical, not a reflection of character, takes a lot of weight off. The MS Trust suggests counselling can help reassure you and your family that it is not your fault.

Family and friends can help by staying calm, not taking an episode personally and giving the person a minute rather than asking them to explain. Telling people in advance, perhaps with a short card or message, can reduce embarrassment at work and in social settings.

Practical steps include noting common triggers, taking a few slow breaths, changing position or focus, and planning breaks. The Stroke Association also lists mental health and emotional wellbeing services for people who find feelings hard to cope with, and the NHS 111 service can direct people to help.

If you ever feel hopeless or think about harming yourself, speak to a GP urgently or call NHS 111. In an emergency, call 999. Samaritans can be reached free on 116 123.

Start by telling your GP, specialist nurse or neurologist about the episodes and how they affect you. If you have a stroke, MS or MND team, they are well placed to review it. Bring a family member if possible.

Where a private consultation is an option, a consultant neurologist can review the pattern, rule out other causes and discuss treatment. The prescribing principles and the importance of assessing mood alongside PBA stay the same.