The findings provide more proof that safeguarding people's mental health could prevent dementia.
Psychotic disorders may be more closely associated to dementia than other mental diseases like depression or anxiety, according to a recent systematic review and meta-analysis that was published in the journal Psychological Medicine. Researchers from University College London reviewed the evidence and found that persons with psychotic illnesses like schizophrenia are 2.5 times more likely to eventually develop dementia than people without a psychotic disease. They discovered that getting a diagnosis of a psychotic disease is connected to a significantly increased chance of developing dementia later in life, according to senior author Dr. Jean Stafford (MRC Unit for Lifelong Health & Ageing at UCL).
It is the first high-quality systematic review to examine the relationship between a variety of psychotic conditions and the risk of dementia. Schizophrenia and other psychotic disorders that are similar to it are serious illnesses that include social withdrawal, hallucinations, and other psychotic symptoms. Additionally, a large number of persons have cognitive and functional skill deficits.
The researchers collated information from 11 studies with a combined total of over 13 million participants that were carried out in nine different countries on four continents. They found that across several psychotic diseases, there was a higher risk of dementia later in life, regardless of the age at which someone first had their mental illness. Some investigations followed patients who had been given a psychotic disorder diagnosis as young adults for decades. They also found that those who have a history of psychotic diseases are substantially more likely to be diagnosed with dementia while they are still in their 60s.
The results extend the number of dementia risk variables that can be changed. According to prior research from UCL, addressing risk factors over the lifespan could prevent or postpone the onset of dementia in four out of every ten cases. While depression and anxiety significantly raise the risk of dementia, according to earlier research by the present study’s co-senior author, Dr. Vasiliki Orgeta (UCL Psychiatry), these most recent data point to psychotic illnesses as having the largest correlation with dementia risk.
The cause of the association, whether it be the mental illness itself or perhaps because psychotic disorders raise the chance of conditions that raise the risk of dementia, could not be determined by the researchers.
Some of the studies had extremely long follow-up periods and included participants who had psychosis at young ages, suggesting this is not the only explanation. The association may in part be explained by the possibility that psychotic symptoms serve as early indicators of dementia in some individuals.
Dr. Orgeta said: “People with psychotic disorders are more likely to have other health conditions such as cardiovascular disease or obesity, which can increase the risk of dementia, while they are also more likely to have a poor diet, smoke or use drugs, which may harm their health in ways that could increase their likelihood of developing dementia.”
Lead author Sara El Miniawi (UCL Psychiatry), who completed the research as her MSc dissertation, said: “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.”
Because there was insufficient and inconsistent evidence, the researchers were unable to identify whether effective treatment for psychotic disorders could reduce the risk of dementia or whether antipsychotic medication could be a factor.
Sara El Miniawi added: “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.”
Parvathy Sukumaran 
