Pseudodementia (otherwise known as “depression-related cognitive dysfunction”) is a condition whose presenting symptoms appear as dementia, but may result from a misdiagnosis of depression, or the adverse effects of medications being taken. This form of dementia is not the true form and does not result from the same cognitive changes. Once the depression is properly treated or the medication therapy is changed, the cognitive impairment can be effectively reversed. Generally, dementia involves a steady and irreversible cognitive decline but in some cases there may be different outcomes. In addition, diminished mental capacity and social withdrawal are commonly identified as symptoms in the elderly but oftentimes is due to symptoms of depression. As a result, elderly patients are often misdiagnosed especially when healthcare professionals do not make an accurate assessment.
Pseudodementia is a phenotype approximated by a wide variety of underlying disorders. Data indicate that some of the disorders that can convert to a pseudodementia-like presentation include depression (mood), schizophrenia, mania, dissociative disorders, Ganser syndrome, conversion reaction, and psychoactive drugs. Although the frequency distribution of disorders presenting as pseudodementia remains unclear, what is clear is that depressive pseudodementia, synonymously referred to as depressive dementia or major depression with depressive dementia, represents a major subclass of the overarching category of pseudodementia. It has long been observed that in the differential diagnosis between dementia and pseudodementia, depressive pseudodementia appears to be the single most difficult disorder to distinguish from nosologically established "organic" categories of dementia, especially degenerative dementia of the Alzheimer type. Depressive pseudodementia is a syndrome seen in older people in which they exhibit symptoms consistent with dementia but the cause is actually depression.
Older people with predominantly cognitive symptoms such as loss of memory, and vagueness, as well as prominent slowing of movement and reduced or slowed speech, were sometimes misdiagnosed as having dementia when further investigation showed they were suffering from a major depressive episode. This was an important distinction as the former was untreatable and progressive and the latter treatable with antidepressant therapy, electroconvulsive therapy, or both. In contrast to major depression, dementia is a progressive neurodegenerative syndrome involving a pervasive impairment of higher cortical functions resulting from widespread brain pathology.
If effective medical treatment for depression is given, this can aid in the distinction between pseudodementia and dementia. Antidepressants have been found to assist in the elimination of cognitive dysfunction associated with depression, whereas cognitive dysfunction associated with true dementia continues along a steady gradient. In cases where antidepressant therapy is not well tolerated, patients can consider electroconvulsive therapy as a possible alternative. However, studies have revealed that patients who displayed cognitive dysfunction related to depression eventually developed dementia later on in their lives.
The development of treatments for dementia has not been as fast as those for depression. Thus far, cholinesterase inhibitors are the most popular drug used to slow the progression of the disease and improves cognitive function for a period of time.
History and controversy of term
The term was first coined in 1961 by psychiatrist Leslie Kiloh, who noticed patients with cognitive symptoms consistent with dementia who improved with treatment. Reversible causes of true dementia must be excluded. His term was mainly descriptive. The clinical phenomenon, however, was well-known since the late 19th century as melancholic dementia.
Doubts about the classification and features of the syndrome, and the misleading nature of the name, led to proposals that the term be dropped. However, proponents argue that although it is not a defined singular concept with a precise set of symptoms, it is a practical and useful term which has held up well in clinical practice, and also highlights those who may have a treatable condition.
Presentation and differential
The history of disturbance in pseudodementia is often short and abrupt onset, while dementia is more often insidious. Clinically, people with pseudodementia differ from those with true dementia when their memory is tested. They will often answer that they don't know the answer to a question, and their attention and concentration are often intact, and they may appear upset or distressed. Those with true dementia will often give wrong answers, have poor attention and concentration, and appear indifferent or unconcerned. The symptoms of depression oftentimes mimic dementia even though it may be co-occurring
The implementation and application of existing collaborative care models such as DICE can aid in avoiding misdiagnosis. Comorbidities (such as vascular, infectious, traumatic, autoimmune, idiopathic, or even malnourishment) have the potential to mimic symptoms of dementia. For instance, studies have also shown a relationship between depression and its cognitive effects on everyday functioning and distortions of memory.
Investigations such as PET and SPECT imaging of the brain show reduced blood flow in areas of the brain in people with Alzheimer's disease, compared with a more normal blood flow in those with pseudodementia.
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