This is a good distinction to kee in mind
Proximal cause is the mechanism of disease. In cancer, a proximal cause is a mutation in a tumor suppressor gene that leads to unregulated cell replication. In AIDS, the proximal cause is infection with HIV.
Distal cause, by contrast, is about risk. For cancer, a distal cause might be smoking; for AIDS, this might be risky sexual behavior. If proximal causes are mechanisms, distal causes influence probabilities.
The distinction between distal and proximal cause is important because distal causes rarely point to treatment targets. Instead, like smoking and risky sexual behavior, they point to prevention targets.
These two versions of cause are frequently conflated when we think about mental disorders. The proximal causes of depression or schizophrenia are almost certainly neural events that lead to altered regulation of mood or thinking. While we have not identified these specific neural events, science is closing in on the circuits and molecular pathways involved. This search is critical because, based on experience with cancer and AIDS, defining these pathways will lead to new, targeted treatments. Proximal causes can be the basis of precision medicine.
The distal causes are quite different. Early childhood adversity or stress during adulthood are distal causes that increase the probability for many forms of psychopathology. Genome-wide associations are, like family history, almost certainly distal causes that increase risk for mental disorders but may not be tied directly or simplistically to the mechanism of disease.
The distinction between distal and proximal cause is important because distal causes rarely point to treatment targets. Instead, like smoking and risky sexual behavior, they point to prevention targets. And rather than predisposing someone to a specific disease, they increase risk for multiple negative outcomes.
Distal causes are not really causes in the traditional sense; they are risk factors. Risk factors are vital for public health interventions and for understanding population-level patterns of disease. But risk factors may not point to treatment targets and they may not be actionable for an individual who has already developed the disease.
…When the notion of cause arises, best to consider precisely what cause means and its value for either treatment or prevention.