University of Sussex psychologists found a link between depression and an acceleration of the rate at which the brain ages. Scientists have previously reported that people with depression or anxiety have an increased risk of dementia in later life. However, this is the first study that provides comprehensive evidence for the effect of depression on decline in overall cognitive function (also referred to as cognitive state), in a general population.
Linking Depression to Cognitive Decline
This study was published in the journal Psychological Medicine on May 24, 2018. Researchers conducted a robust systematic review of 34 longitudinal studies. It focused on the link between depression or anxiety and decline in cognitive function over time. Evidence was combined and reviewed from more than 71,000 participants. Included in the study were people with symptoms of depression as well as those diagnosed as clinically depressed. The study looked at the rate of decline of overall cognitive state. This encompassed memory loss, executive function (such as decision making) and information processing speed – in older adults.
Participants were excluded from the analysis if diagnosed with dementia at the start of study. This enabled the assessment to focus more broadly on the impact of depression on cognitive aging in the general population. The study found, people with depression experienced a greater decline in cognitive state in older adulthood than those without depression. It is important to note, there is a long pre-clinical period of several decades before dementia may be diagnosed. Consequently, the findings of this study are important for early interventions as currently there is no cure for the disease.
Understanding the Implications of this Research
The lead authors of the paper are Dr Darya Gaysina and Amber John from the EDGE (Environment, Development, Genetics and Epigenetics in Psychology and Psychiatry) Lab at the University of Sussex. They are calling for greater awareness of the importance of supporting mental health to protect brain health in later life.
Dr Gaysina, a Lecturer in Psychology and EDGE Lab Lead, comments: “This study is of great importance – our populations are aging at a rapid rate and the number of people living with decreasing cognitive abilities and dementia is expected to grow substantially over the next thirty years.
“Our findings should give the government even more reason to take mental health issues seriously and to ensure that health provisions are properly resourced. We need to protect the mental wellbeing of our older adults and to provide robust support services to those experiencing depression and anxiety in order to safeguard brain function in later life.”
Researcher Amber John, who carried out this research for her PhD at the University of Sussex adds: “Depression is a common mental health problem – each year, at least 1 in 5 people in the UK experience symptoms. But people living with depression shouldn’t despair – it’s not inevitable that you will see a greater decline in cognitive abilities and taking preventative measures such as exercising, practicing mindfulness and undertaking recommended therapeutic treatments, such as Cognitive Behaviour Therapy, have all been shown to be helpful in supporting wellbeing, which in turn may help to protect cognitive health in older age.”