Researchers from University College London (UCL) have found that people with psychotic disorders like schizophrenia are two and a half times more likely to be diagnosed with dementia than those with other mental conditions like depression or anxiety.
The systematic review and meta-analysis study published in the journal Psychological Medicine on October 6 collected evidence from 11 different studies across nine countries and four continents, scanning 13 million participants overall. They observed a range of severe mental disorders and their association with dementia risk.
Dementia is a set of symptoms often seen in advancing years and associated with forgetfulness, limited thinking and social skills, impacting daily functioning. It affects brain functions like memory, thinking, reasoning, mood and behaviour.
Dr Vasiliki Orgeta, the joint senior author of the current study, had previously found that post-traumatic stress disorder (a mental health condition triggered by a traumatic event), depression and anxiety could increase the likelihood of developing dementia.
The current study found a stronger link between psychotic disorders and dementia risk regardless of the age at which the person develops the mental condition.
“Cognitive impairment and hallucinations can be symptoms of both dementia and psychotic disorders, so it is possible there could be a link between the two illnesses. This impairment could also limit people’s cognitive reserve and increase their vulnerability to dementia symptoms,” lead author of this study, Sara El Miniawi said in a statement.
The study also found that people with psychotic disorders are diagnosed with dementia in their 60s — earlier than the average age of dementia diagnosis.
However, the researchers could not find the exact cause of the association between severe mental disorders and determine if effective treatment for these disorders could reduce the risk of dementia.
“As people with psychotic disorders face a higher risk of numerous other health conditions, managing their overall physical and mental health is very important, and here we found that health professionals working with them should also be watchful for any signs of cognitive decline,” El Miniawi said.
This study is in line with the previous findings of researchers from UCL, which suggest that by targeting the risk factors throughout the lifespan, 4 out of 10 dementia cases can be delayed or prevented.