Depressive Pseudodementia

Depressive pseudodementia refers to a set of clinical features where partial or total cognitive impairment predominates. Learn more.

Written and verified by la psicóloga Paula Villasante.

Last update: 22 May, 2023

The concept of depressive pseudodementia has generated controversy among researchers and theorists on the subject. Wernicke seems to be the one to first use this concept upon observing patients who imitated mental deficiencies and presented pictures of chronic hysteria. Later, other researchers used the term based on other works.

Today, the term pseudodementia refers to a set of general clinical features in which partial or total cognitive impairment predominates, secondary to depressive symptoms. Most of them are reversible clinical pictures with medical treatment. However, a proportion of depressed elderly with cognitive impairment can evolve into irreversible dementia.

Therefore, we could say that depressive pseudodementia is on the border between dementia and depression. However, the entity doesn’t seem well-defined and reaches diagnostic relevance in clinical, evolutionary, and response aspects.

It seems that depressive pseudodementia remains a valid term in clinical practice, even with its diagnostic limitations. It facilitates the approach, diagnosis, and treatment of patients with mixed cognitive and depressive symptoms.

Depressive pseudodementia: What is it?

Depressive pseudodementia is a major depressive disorder in which cognitive deficits secondary to the affective disorder are so significant that healthcare providers are forced to consider dementia as a differential diagnosis.

The relationship between depression and dementia is complex and intricate. Even after depressive pseudodementia has subsided, certain cognitive deficits may persist and the risk of developing dementia is increased. The concept of depressive pseudodementia remains useful in clinical practice despite its limitations.

On the other hand, the controversy over the existence of pseudodementia as a specific clinical picture derives from the evidence of depressive states in different intensities. In addition, its causal or bidirectional relationship with the deterioration of various intellectual functions plays a role, which, in most cases, can be reversible.

Regarding the term “pseudodementia”

The term pseudodementia (PDEM) was coined by Kiloh (1961) to describe cases that closely mimicked the image of dementia. Since then, the term has been used to describe the cognitive profile of various psychiatric disorders, especially depression in old age, which course with cognitive decline in dementia.

Since the term entered academic usage, there have been various arguments against its use, as well as in favor of it. Despite these arguments, pseudodementia remains an important descriptive denotation to describe cognitive deficits in psychiatric disorders, especially depression.

Clinically, the term “depressive pseudodementia” has become synonymous with the cognitive deficits seen in patients with major depressive disorder. As the term means, it’s the clinical condition that appears with the picture of full-blown dementia, but in reality, it’s a different entity. This means that this condition actually has two components, which are also reflected in its name:

• “The dementia component,” which is the combination of various cognitive deficits found in these psychiatric disorders and
• “The pseudo-component,” denoting the actual lack of neurodegenerative dementia.

Depressive pseudodementia: A clinical picture as such?

The situations that lead to debate among experts and researchers are the following:

• Depressive states in the elderly, especially major depression, show cognitive deficits, but their causal relationship isn’t clear, as in some cases they may be coexisting entities.
• The elderly can develop a total or partial intellectual deficit of progressive development from early ages of life and, at some point, present a depressive state for different causes. These deficiencies aren’t due to the onset or continuation of dementia: They’re simply the normal deficiencies of aging and, therefore, they’ll be maintained or will progress regardless of the evolution of the depressive state.
• In the initial and intermediate stages of dementia, and due to the perception and awareness of their cognitive deterioration, the elderly in a reactive way may present an anxious and depressed state.
• Some behaviors and mental functioning, characteristic of the elderly (for example, slowing down), can be confused with depressive symptoms or intellectual deterioration, without really being so.
• Due to organic, psychological, and social etiological factors, both depressive symptoms and intellectual deficiencies can be reinforced or become causes or precipitants of the constellation of one of the two entities.
• The diagnostic criteria, and essentially the concept of pseudodementia, have been used differently by the various groups of researchers, which has generated confusion about what’s involved, by assuming the relationship between depressive states and clinical cognitive impairment, permanent or reversible.

More data on depressive pseudodementia

• The use of neuropsychological scales and tests aren’t specific for pseudodementia and the results may correspond to other incipient or ongoing depressive or dementia states, the normal aging process, individual or population differences, the affectation of mood and intellect by to chronic or acute organic diseases and by the use or abuse of medications and substances, the impact of psychosocial and educational factors, and the validity of the instruments used.
• There are no biological markers for pseudodementia as such; Those from studies of dementia or depressive states are used, based on the different hypotheses and causal theories. Neuroimaging techniques are also not specific for the diagnosis of depressive pseudodementia and its differentiation with major depression and Alzheimer’s type dementia.
• The concept of pseudodementia has been used with the characteristic that cognitive deficits are reversible by improving the baseline depressive state; however, some depressed elderly may present deficits as part of their aging process in a progressive manner or evolve towards frankly demented states in later stages of life.
• Most of the studies on pseudodementia don’t refer to this concept specifically and are based more on the findings of Alzheimer’s or frontotemporal dementia and its relationship with major depression, which creates more confusion when trying to elucidate whether pseudodementia is in itself a psychopathological state, the object of being taken to the nosological category, or if it’s a syndrome that’s “embedded or intermediate” between depressions and dementias.

Epidemiology

According to estimates, depression affects 10% of healthy older adults and 25% of those with a chronic disease.

Diagnosis

Regarding the diagnosis of depressive pseudodementia, it tends to be clinical. In any case, it’s convenient to consider the onset of the symptoms and the evolutionary progression. Neurodegenerative dementias usually start slowly and progressively. Meanwhile, progressive pseudodementia has a subacute onset, great functional impact, and rapid evolution that’s disproportionate to cognitive impairment.

In depressive pseudodementia, unlike other neurodegenerative pictures, there’s awareness about the disease. In addition, those who suffer from it tend to be concerned about their condition.

Otherwise, patients suffering from this disease meet the diagnostic criteria for a major depressive episode and usually present greater symptoms in the morning. In contrast, in dementia, an evening aggravation of symptoms is often observed.

Somatic discomfort and motor retardation predominate in depressive pseudodementia, especially in older people.

Treatment

As regards the evidence regarding the treatment of depressive pseudodementia, this is scant. They’re mainly based on extrapolation from studies on major depression in adult patients.

Treatment is started gradually and slowly until the minimum effective dose is reached. In cases of depression with cognitive deficiencies, apart from the research in this regard, antidepressant treatment with donepezil is recommended. However, there’s no conclusive evidence to recommend this drug against depressive pseudodementia.

On the other hand, electroconvulsive therapy is also a valid option for depressive pseudodementia. Psychotherapy may also be beneficial in older adults, although there are no solid data in this regard.

Finally, physical activity also has positive effects on patients with depressive dementia.

The relationship between dementia and depression

The relationship between dementia and depression has been so complex that it’s sometimes difficult to clinically distinguish between the two.

Depression and dementia are two of the most common conditions in clinical practice. Therefore, they can coexist or, sometimes, they can occur independently.

The clinical term “pseudodementia” has remained a permanent disease entity in literature for more than 100 years. Recognition of the fact that clinical symptoms associated with reversible neuropsychiatric conditions can mimic irreversible disorders was known as early as the mid-19th century.

To this day, the diagnosis of pseudodementia has been facilitated. In fact, a study carried out in 1989 reports the use of EEG to distinguish depressive pseudodementia and dementia with secondary depression.

In 2000, a study showed that sleep polygraphy was the best diagnostic tool for distinguishing dementia and depression in patients with pseudodementia.

However, these tests have their own limitations, making clinical differentiation between dementia and depression difficult to this day. Being one of the most common psychiatric diseases, science still doesn’t have a reliable method for its clinical diagnosis.