Predicting Cancer from Depression: A Systematic Review of Prospective Studies

Past research has proposed depression as a risk factor for developing cancer. Because results of previous prospective epidemiological investigations are found to be conflicting and inconclusive, the current review evaluates the substantiation of cancer resulting from depression by reviewing prospective cohort studies.  Identified studies, through a sensitive search strategy with the help of keywords, from Medline and Embase were retrieved as per the developed protocol and the PRISMA 2009 recommendations. The screening for the relevance of studies and the entire process of selection was done with criteria. A validated checklist ensured methodological quality whereas accuracy was made certain by double-data extraction technique. Results suggest a possible causal link between depression and the risk of cancer. When chronic and severe depression predicted greater risk of cancer, findings are inconclusive on the link between less severe depression and cancer. With the high prevalence of mood disorders, this review draws the attention towards a common biological pathway linking depression and cancer. This also highlights the necessity to discover means to control it, and hints the toxic effect of depression on risk factors in elevating the risk of cancer. Research and clinical implications are also dealt.