One form of psychological treatment that has a strong evidence basis and which is relevant to a discussion of the links between brain and behaviour in explaining the 'causality' of depression is that which is commonly referred to as "Behavioural Functional Analysis".
Our cross-sectional methodology makes it difficult to draw definitive conclusions about the causality of anxiety and depression in this population, and how these conditions vary over time.
The temporal relationship between depression and insulin resistance has not been clearly delineated, because the majority of studies, including this one, have been cross-sectional; thus, we are limited in our ability to infer causality in the etiology of depression related to insulin resistance.
Although integration has been found to be related to a lower risk of depression, its causality and implications for prevention and clinical practice should be examined in more detail for example the potentials of including it as component in screening or treatment strategies.
By adjusting for these, this study reduced the potential bias from reverse causality in the estimate of risk of depression.
Violence can be a trigger for depression and anxiety symptoms; and although reverse causality is an issue, the prevalence of depression during pregnancy has been shown to be four times higher in pregnant women exposed to violence compared to women not exposed[ 51].
This meta-analysis is based on descriptive uncontrolled data which do not allow us to determine specific causality between OvCa and the reported prevalence of depression and anxiety.
Increasing use of genome-wide-association studies, exome sequencing, and whole-genome sequencing will make it possible to do Mendelian randomization studies that assess the causality of hypnotic associations with excess depression, infection, cancer, and mortality.
Although the present study has a cross-sectional design, preventing us from making any conclusions as to the causality of ω-3 FA intake and depression, it seemed unlikely that depression would change the intake of ω-3 FA.
Further research is required into whether the associations are causal, the direction of causality, and whether obesity interventions can reduce the risk of depression.
