A team of scientists in Canada has found that people with a history of neurological and psychiatric disorders are potentially at an increased risk of developing future mental conditions.
The research, performed by experts from the University of Waterloo and the Institute for Clinical Evaluative Science, identified that individuals who previously had either neurological or psychiatric disorders were at an elevated risk of future mental comorbidities.
The study was conducted in Ontario and is the largest, both in terms of populations size and study duration. The investigation is the first to analyse the effect of being a man or a woman on the development of neurological and psychiatric conditions, with results also showing that sex significantly increases the risk.
Colleen Maxwell, a professor at the School of Pharmacy at Waterloo and lead author on the study, commented: “Globally, neurological and psychiatric disorders are leading causes of disability and death. Understanding which disorders or conditions are risk factors for, or early manifestations of, later disorders will help healthcare providers and family provide proactive care for individuals living with these conditions.”
The project, which is published in the journal Age and Aging, received funding from funding from the Neurodegenerative Disease Research Initiative (ONDRI), which supported the research through the Ontario Brain Institute.
Risk of future neurological and psychiatric disorders
For their investigation, the team employed provincial health databases to analyse data from more than five million residents in Ontario aged between 40 and 85 years. Over a period of 14 years, the researchers studied the association between pairs of common neurological disorders, including dementia, Parkinson’s disease, or stroke, and psychiatric disorders such as depression and anxiety.
They examined the link between this range of conditions in both directions, such as investigating how previously experiencing a stroke related to a future risk of dementia and vice versa. For the majority of cases, the team identified that the rate of developing a second condition increased; for example, people previously diagnosed with Parkinson’s disease were found to have four times increased risk of developing dementia.
Moreover, those with a prior stroke had more than double the risk of developing dementia. Additionally, the research suggested that having previous psychiatric disorders was associated with an increased rate of developing dementia later in life. For some conditions, the chances of developing the second disorder persisted for ten years or more after the first.
Different impacts for men and women
The study results demonstrated that women and men differed in their risk of developing future conditions after experiencing an earlier one. One example is when evaluating the men and women who experienced an earlier stroke, women were much more likely than men to develop dementia late in life.
The team is hopeful that their research can aid in not just improving care for individuals with these conditions but also enhancing the planning of health systems as a whole.
Maxwell concluded: “We also hope to provide information for those designing medical, educational programs to ensure healthcare providers are informed of and equipped to address these common comorbidities.”