Cognitive (memory) impairment may be associated with a number of functional psychiatric disorders. These conditions may be confused or mixed with true dementia, but the cognitive impairment can reverse if the underlying cause is adequately treated. A person with severe depression may present with depressive pseudodementia.
Features of depression are usually present - one or more of the following:
(1) history of depression
(2) depressed mood at onset of cognitive impairment
(3) patient looks depressed during interactions
Features of the cognitive impairment:
(1) rapid onset (rather than gradual)
(2) fluctuating severity
(3) decreased memory for recent events
(4) confusion
(5) usually better oriented than the typical dementia patient
(6) pathologic reflexes are absent
(7) ability to perform calculations usually preserved
The patient may show symptoms seen in depressed patients:
(1) fatigue and/or motor retardation
(2) anxiety
(3) delusions and/or psychosis
The cognitive impairment
(1) often improves if the patient is placed on adequate antidepressant therapy
(2) may improve if the person experiences sleep deprivation (Southmayd)
Differential diagnosis:
(1) mixed dementia and pseudodementia
(2) pseudodementia associated with other psychiatric conditions
(3) drug-induced depression (may show variability as serum drug levels change)
