Leslie Gordon Kiloh was an influential Australian neurologist who, in 1961, introduced the term “pseudodementia” to describe a syndrome in which psychiatric conditions—most commonly depression—produce symptoms that closely resemble those of dementia. His observations highlighted the importance of distinguishing between neurodegenerative diseases and psychiatric disorders that impair cognition, especially in older adults.

Pseudodementia refers to cognitive impairment that is not caused by irreversible brain damage, but rather by psychiatric conditions like major depressive disorder. People with pseudodementia often complain of memory problems, difficulty concentrating, and slowed thinking. These symptoms may appear similar to those seen in Alzheimer’s disease or other forms of dementia, but the underlying cause is functional, not structural.

One of the key features of pseudodementia is that the patient is usually aware of their cognitive difficulties and may be distressed by them. Patients often describe their symptoms with concern and may respond to memory questions with phrases like “I don’t know.” This contrasts with many dementia patients who may be unaware of the extent of their deficits.

The onset of pseudodementia is usually sudden or subacute, and patients may show signs of low mood, anxiety, sleep disturbances, or social withdrawal. On neuropsychological testing, their effort may be poor, and performance may vary depending on mood and motivation. Brain imaging typically does not show the types of changes seen in neurodegenerative conditions.

The good news is that pseudodementia is often reversible. With proper treatment of the underlying depression—using antidepressants, psychotherapy, social support, and lifestyle changes—many patients experience significant improvement in their cognitive functioning.

Recognizing pseudodementia is crucial. Misdiagnosing it as a progressive dementia can lead to unnecessary medications, increased patient distress, and lost opportunities for effective treatment. Clinicians should maintain a high index of suspicion, especially when cognitive symptoms develop quickly or when mood symptoms are prominent.

Leslie Kiloh’s contribution remains vital to both neurology and psychiatry. His insight serves as a reminder that not all memory problems point to dementia—and that, with accurate diagnosis and appropriate care, recovery is possible.