I’m often asked about delusions in the setting of dementia. A delusion is defined as a fixed, false belief that is out of keeping with the person’s usual way of viewing the world, and that is not modifiable by presentation of evidence to the contrary. Delusions are considered a psychotic symptom, and thus it seems entirely reasonable to treat them with antipsychotics. Or is it?
Certain ‘delusions’ seem very specific to people living with dementia. “That man is not my husband... people are stealing things from me… I have to get home to look after the children... my family have put me here because they want to take my house.” The list goes on. Why are these beliefs (and many others) restricted to people living with dementia? I’ve never heard anyone with schizophrenia, for example, hold these specific beliefs.
I’d like to suggest that this is because these particular fixed, false beliefs arise as artefacts of memory, rather than because of psychosis. You lose something, but are SURE you know where you put it… someone therefore MUST have stolen it! You can’t understand why your family has placed you in care… maybe it’s because they want my house, or maybe it’s so my partner can have an affair? These are all understandable rationalisations when one adopts the perspective of the person living with dementia.
Many doctors will think as follows: delusions = psychosis = the need for an antipsychotic. Is it likely that these beliefs, arising via this mechanism, will be antipsychotic responsive? Rather than reporting that a client is ‘delusional,’ it’s much more helpful to describe what the person is actually saying, so that a considered decision can be made regarding the origin of these beliefs. Not all delusions are psychotic!
A/Prof Steve Macfarlane is the Head of Clinical Services at DSA. He is a geriatric psychiatrist and spent 11 years working as the Director of two metropolitan public-aged psychiatry services in Melbourne, prior to helping establish the Severe Behaviour Response Team in 2015.