Does Stress Cause Depression?
What exactly is a stressful experience? We can look at it in different ways. First, we have negative life events such as divorce or bereavement. There are the everyday hassles to which most of us are exposed. Then we might consider more chronic difficulties such as living with a disease or disability, or perhaps being a caregiver for someone with a long-term disease. Last, but not necessarily least, are the childhood experiences that help to shape our view of the world and our place in it.
In my first few years working in mental health, depression tended to be described in one of two ways. Reactive depression was thought to result from stressful life events and the prognosis was considered more favorable than those with endogenous (from within) depression. In fact there is very little evidence to support such differences. Even the so-called endogenous depressions tend to be triggered by stressors and the clinical features and treatments of the two are similar.
We know that loss, is one of the key ingredients for depression. Interpersonal loss, in the form of bereavement, separations, endings, or even the threat of such things, have a negative effect on the self-worth of people, some of whom may be especially vulnerable. There is evidence to suggest such events frequently precede depression and may indeed be one of the most common issues. But loss isn't simply to do with relationships. Loss can be extended beyond the interpersonal to include, for example, loss of employment, status and loss of self-esteem.
Having said this, the fact remains that even in the face of extreme stress, most people do not go on to develop major depression. This leads us to the notion that some people must have a particular vulnerability and this is where things begin to get tricky. Most of the current thinking around this vulnerability talks of an interplay between biology, social circumstances and psychology. The complexity of such models makes analysis extremely difficult.
There is evidence that stress can lead to depression but we can't assume this is a one-way relationship. The personal characteristics of individuals also means that depression can result in stressful events. Whatever the relationship, it appears that the stress-depression link is far from static. The nature of the relationship is complex and may even change for the individual over time.