A meta-analysis of studies examining links between cognitive ability and depression symptoms found no association between cognitive ability in childhood and depression in adulthood. The association was absent even after looking at different ages of assessment and in both genders. The research was published in the Journal of Affective Disorders.
Cognitive abilities are the mental skills that one needs to carry out any task from the simplest to the most complex. These abilities encompass a range of mental processes related to the manipulation of information, such as perception, memory, logic and reasoning, and attention.
Memory, both short-term and long-term, plays a crucial role in cognitive abilities, as it helps store and retrieve information when needed. Logical reasoning and problem-solving depend on the ability to analyze information, generate connections, and make decisions based on the data available. Additionally, cognitive abilities are crucial for language understanding and expression, enabling complex communication and learning processes.
Individuals with good cognitive abilities tend to perform better in various domains of life. Some authors believe that cognitive ability can even be treated as an overall measure of how well the body is functioning. In support of this, large longitudinal studies report that individuals with lower cognitive abilities are more likely to die prematurely or contract various diseases. These findings have led researchers to investigate whether a correlation exists between cognitive ability in childhood and depression in adulthood.
Study author Emily L. Ball and her colleagues wanted to integrate findings of such studies. They focused on the links between childhood cognitive ability and depressive symptoms in adulthood. These authors reasoned that depression often starts in early adulthood, but is rarely detected in childhood. If we consider cognitive ability a measure of overall functioning of the body, it is possible that depression or precursors of depression in childhood might manifest themselves as lower cognitive abilities.
The researchers searched scientific databases including EMBASE (OVID), MEDLINE (OVID), PsycINFO (EBSCO), Science Citation Index, and Social Sciences Citation Index for studies on childhood cognition and depression. They also reviewed studies cited by the papers they found. Their search strategy focused on three key themes: childhood cognition, depression, and study type, employing a set of terms related to these themes.
In the end, their search yielded 18 scientific articles, which included data from 19 different groups of study participants, totaling 84,407 individuals. Depending on the group, between 44% and 100% of participants were female. Of these groups, nine were from the U.S., five from the U.K., two from New Zealand, and one each from Australia, Canada, and Spain. All groups were from higher-income countries.
The cognitive abilities of the study participants were assessed at ages ranging from 4 to 18 years, using various neurocognitive tests. The average age for the assessment of depression symptoms in these studies ranged from 18 to 84 years. Very few studies assessed depression symptoms after the age of 60.
The meta-analysis of these studies revealed no association between cognitive ability in childhood and depressive symptoms in adulthood. This absence of correlation held even when considering different ages of assessment and across both genders.
“In conclusion, this systematic review did not find an association between childhood cognitive ability and risk of depression in adulthood. Rather, it highlighted mixed findings of the existing literature, and emphasized the challenges in controlling for potential confounders when understanding key risk factors for depression across the life course,” the study authors conclude.
The study makes an important contribution to the scientific understanding of the relationship between depression and cognitive abilities. However, it should be noted that the vast majority of studies included in this meta-analysis came from the U.S. and the U.K, and that all the other data also came from high-income countries. Results might not be the same in non-Western cultures and lower-income countries.
The paper, “Cognitive ability in early life and risk of depression in adulthood: A systematic review and meta-analysis,” was authored by Emily L. Ball, Laura Morillo, Elizabeth Poyner, Andrew M. McIntosh, and Matthew H. Iveson.