Most of us have heard about the BioPsychoSocial model of mental illnesses and have also heard about the stress-diathesis model. Today as I was contemplating the two, taking cue from my ABCD model of psychology, I tried combining the two and find quite some merit in that approach.
To recap, BioPsychoSocial model says that any disease is a result of multiple interacting factors- some of them biological in nature while others psychological and social. The mind affects the body and the body affects the mind and together they may lead to health or illness. This model is as opposed to the BioMedical model which considers the disease to be predominantly due to biological factors.
The stress-diathesis model posits that people have underlying biological or psychological vulnerabilities and when exposed to an environmental stressor may develop a mental disease with varying probabilities. The same stressor may be harmless to a person who does not have those many vulnerabilities, but prove detrimental for someone with the right kind of vulnerabilities.
Combining the two models together, one can have biological, psychological or social diathesis or vulnerabilities and when exposed to the right environmental toxin/stressor may lead to the emergence of a mental health issue in the individual.
To elucidate by way of an example. Consider a person whose serotonin neurotransmitter system is such that he typically has lower levels of baseline serotonin. This would be a biological vulnerability to depression. He also has tendency towards negative automatic thoughts or pessimism. This would be a psychological vulnerability. Moreover he has limited social support and is unmarried and from a low SES background. This would be the social vulnerability. Strike three. On top of this, lets say he suddenly loses hos job and is laid off. That environmental life event may be enough to drive this person to clinical depression.
The BioPsychSocioEnvironmental model has application not only in psychopathology, but I believe its a powerful framework for normal development too. For e.g., if we replace diathesis-stress model with differential susceptibility thesis then the diathesis or sensitivity to context can interact with both positive and negative environmental events to lead to positive or negative life outcomes.
To me combining the two models is immensely fruitful; hope you too find it useful.