Pseudobulbar Affect: Diagnosis in the Midst of Depression

Pseudobulbaa affect (PBA) typically presents as episodes of uncontrollable laughing or crying that is out of context to the current social situation. The patient’s emotional expression is incongruent to their emotional state. Usually, PBA is seen in the setting of other neurologic diseases such as ALS, Parkinson’s disease, Alzeihmer’s dementia, stroke, progressive MS, brain tumors, traumatic brain injury and others.

The true prevalence of PBA is unclear as it can vary vastly depending on the underlying neurological disease, the methodology of the study being done, and the criteria used to diagnose it. Depending on the scale and threshold score used to identify cases, the range has been reported form a low of 0.55 million to a high of 7.1 million patients. In six neurologic conditions studied, the prevalence ranged from 10 to 38%. In one study, the incidence of PBA in ALS ranged from 2 to 60%; 7-29% in MS; 10-74% in Alzeihmer’s dementia; 6-52% in stroke; 5-11% in TBI; and 5-17% in PD.

There are several studies demonstrating involvement of the primary neurotransmitter pathways including disruption of glutamate and serotonin transmission. In one study looking at stroke patients, researchers found infarcts in the dorsal globus pallidus, mainly of serotonergic origin. Lesions in patients with PBA have also been discovered in the frontal lobes and the pathways descending into the brain stem, basilar pontine nucleus, and the cerebellum. Impaired cerebellar control of emotion is thought to result from the disruption of the cerebellar neurotransmitter pathways, especially corticopontinecerbellar circuits. Another group of researchers suggest that it is a disinhibition syndrome resulting from disruption in the pathways involving serotonin and glutamate. Additionally, there may be a sensory and motor component playing a role, with the cerebellum acting as a gatekeeper over direct input from the motor cortex as well as the frontal and temporal lobes. Brain mapping studies (MRI/DTI) and EEG suggest that the key components in the dysregulation are reduced dopamine and serotonin neurotransmission and increased transmission of glutamate.

PBA is often misdiagnosed as depression

Since a symptom of PBA is uncontrollable crying, it often is misdiagnosed as depression. Depression is a chronic mental disease that is characterized by changes in mood, thought, behavior and physical health. Symptoms are often recurring and can be life-threatening and the WHO has classified it as a leading cause of disability. Other symptoms include anhedonia, dysphoria, changes in appetite or weight, abnormal sleep patterns, disrupted psychomotor activity, feelings of guilt or worthlessness, problems concentrating, altered decision-making abilities, and recurring thoughts of death or suicide. It is estimated that 450 million people worldwide suffer depression and the lifetime prevalence has been rated as high as 14-17%. In contrast to PBA, there have been numerous studies to define the pathophysiology of depression; yet, the exact mechanism remains elusive.

In fact, depression is the most common PBA misdiagnosis.  The most notable differentiating factor is duration of symptoms. Depression typically lasts weeks to months whereas, PBA episodes last seconds to minutes. In depression, crying may be exaggerated but it is mood-congruent whereas in PBA it is not. Symptoms that may also be seen in depression such as fatigue, appetite changes, anhedonia, sleep disturbance, feelings of hopeless/guilt are not seen in PBA. In comparison to bipolar disorder, PBA episodes have a relatively short duration with no mood changes in between. In BD, there are substantial changes in mood, cognition and behavior in between episodes of rapid cycling.

Another study found that healthcare providers also have a low awareness of PBA. Approximately 74% of patients with PBA reported laughing or crying episodes to their physician. Of those, only 41% were given a specific diagnosis but none were diagnosed with PBA.  Of these patients, 33% were diagnosed as having depression, 9% PTSD, 13% bipolar disorder and the rest told that it was just part of their underlying condition. In 1969, Poeck established criteria for diagnosing PBA in the presence of involuntary laughing or crying.

Poeck Criteria for Diagnosing PBA:

1. Episodes are incongruent to the situation and there are no triggering factors.
2. There is no correlation between the patient’s emotional expression and how they are feeling.
3. Episodes are stereotypical: they build up suddenly to a maximum level and decrease slowly.
4. There are no mood changes associated with these episodes.

One study looked at the association between PBA and ALS patients. Both PBA and depression are usually diagnosed by a structured interview. There are guidelines that exist to distinguish the two diseases as well as self-reporting instruments. In ALS patients, both conditions are prevalent, ranging from 15 to more than 50%. The population of this current study was consecutive patients with ALS treated at a neuromuscular center between August 2006 and January 2015. All patients at the clinic were asked to provide patient-reported outcomes (PROs) during routine visits using tablets in the waiting room.  Approximately 30% of the patients with ALS were also found to have PBA. Of the 1067 patients with ALS, 43% were women and the median age of onset was 60.4 years. Females were significantly more likely to be diagnosed with PBA: 37.8% vs. 21.4%. PBA was found to be more common in those patients with cognitive dysfunction as opposed to those without: 37.9% vs. 26.1%.  Among women, 64.7% cried predominantly whereas 64.4% of men predominantly laughed. Regarding depression, PHQ-9 scores were examined and it was found that there was a highly significant association between crying predominant PBA and depression. Laughter-predominant PBA showed no association with depression. The researchers of this study were able to establish conclusively that the PHQ-9 ad CNS-LS were effective instruments to differentiate between PBA and depression in both populations and individuals.

Nursing home patients were evaluated in another study.  A retrospective study was conducted between 2013 and 2014, looking at 811 nursing home residents in 8 facilities across Michigan. The results of this study were published in the International Journal of Geriatric Psychiatry in November 2015. Approximately half of nursing home residents were found to have a condition predisposing them to PBA. Further conclusions estimated prevalence of 17.5% in this predisposed population and 9% of all nursing home residents. Complicating these results is the fact that twice as many residents with PBA symptoms were likely to be on psychotropic medications and more likely to be on anxiolytics and antidepressants. Many of these patients were thought that their PBA symptoms were the result of their underlying neurologic process and therefore, treated with medications that could cause harmful side effects.  It is thus very important to distinguish PBA from other neurologic or psychiatric conditions to avoid potentially harmful medications which may not be needed or effective. Other medications for PBA are now available.

Do you or someone you care for have PBA?

Please join our education program with PBA specialists, developed especially for patients and caregivers. Register here.