Heredity and childhood trauma are two known risk factors for depression, but these can’t be modified in adults. Are there specific actions that could be taken by at-risk individuals that would make depression prevention possible? Much of the research available so far does not search for a wide variety of possible factors, instead focusing on a hypothesized intervention, e.g. exercise or diet, which may show results, but will not show interactions between factors, or others that may be overlooked.
A large-scale cohort study from the U.K. has looked at patient health questionnaire data including information about mental and physical health, social and community participation, and general lifestyle, as well as genomic data showing possible genetic risk factors. After 6 to 8 years, participants completed a follow-up questionnaire including items designed to find whether they had experienced symptoms of depression.
Statisticians will love reading about how the researchers figured out how to analyze the incidents of depression against past traumatic events and genetic risk factors to discover the effect each of these had on incidence of depression and on how the other factors studied influenced depression in the whole population of study participants. Suffice it to say that a complex process allowed them to determine various levels of risk and how different factors (sleep time, computer use, types of exercise or gym membership and a host of others) impacted negatively or positively the experience of symptoms of depression.
In the full study sample, 49 factors were identified spanning multiple domains (e.g., physical activity, media use, sleep, social, environmental, and dietary variables). These were compared across the entire group and those sub-groups who had shown increased risk of depression based either on genetic factors or on childhood experience of trauma (or both). Three top factors emerged from the analysis as having significant impact either on preventing depression or on increasing the risk of depression.
The top protective action that people can take according to this analysis is “confiding in others”. That is, letting people close to you know that you are struggling and that you appreciate their support. The authors say that,
“the emergence of social factors as the most robust among many other modifiable targets suggests that efforts to counteract disconnection at the societal and individual levels—whether by social activity prescriptions or reducing the stigma of seeking emotional support—should be central to an effective depression prevention agenda.”Karmel Choi, PhD
Two factors: television use and daytime napping emerged from the analysis as important drivers of increased risk for depression. More study is needed on these results to determine exactly what they indicate. In the case of television watching, is it related to screen time alone, or to the content watched? In the case of daytime napping, it is not clear whether it begins to occur after the depression sets in, or is a precursor to depression.
Overall, the study gives robust results for persons who are at heightened risk of depression as well as for the general public. It also serves as an example of research methods that may generate new results from large data bases without possible bias introduced by the researchers’ previous hypotheses. We look forward to hearing more from this source!