Severe depression and psychosis can cause cognitive impairment similar to what’s seen in dementia, but the effects are reversible with the right treatment.

Neurodegenerative diseases affect the neurons in our brain – the working units of our grey matter that transmit signals to other parts of the body and help our day-to-day function.

Dementia and Parkinson’s disease are examples of two neurodegenerative conditions. They currently don’t have a cure and once the neurodegeneration starts, it progressively worsens leading to loss of cognitive ability and in the case of Parkinson’s, movement as well.

Yet there are other conditions that can look like neurodegenerative diseases but aren’t. This is known as pseudodementia and researchers argue it’s important to diagnose because it is possible to reverse the cognitive impairment.

In a systematic review of the findings in this area, Australian researchers looked at the available evidence around the outcomes of patients diagnosed with pseudodementia. They had conditions like severe depression, psychosis, mania and conversion disorder, which can all impair cognitive function.

The researchers found 18 studies involving almost 300 patients and which followed them for up to several years, including whether they progressed to dementia and their mortality.

They found that after a number of years, about a third of those with pseudodementia had progressed to ‘frank,’ or clinical dementia. About half had not, and of those who didn’t, more than 50% had significantly improved since their pseudodementia diagnosis.

When they excluded older people from the analysis, very few of the pseudodementia diagnoses had progressed to dementia, as you’d expect. Some studies also looked at treatments, finding that electroconvulsive therapy and antidepressant medications were helpful in improving the pseudodementia (though that was probably due to the treatment improving the underlying condition, like depression or psychosis).

Implications

The authors say that this review demonstrates the importance of diagnosing pseudodementia, which can sometimes masquerade as a neurodegenerative disease. It is possible to reverse the cognitive impairment it causes, as long as it is identified and treated early.

Last Reviewed: 20/03/2020

© Norman Swan Medical Communications.



References

For reference: Connors, et al (2019). Longitudinal outcomes of patients with pseudodementia: a systematic review. Psychological Medicine doi: 10.1017/S0033291718002829.

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