The Mood Disorders Unit suspects that non-melancholic disorders are primarily caused by psychological processes reflecting an interaction between stress and the individual’s personality. A central feature of ‘depression’ is loss of one’s self-esteem (that is, thinking less of oneself or being increasingly self-critical). Any event, therefore, that impacts on an individual’s sense of self-worth risks precipitating depression.
A common stress event to impact on self-esteem is the break-up of an intimate relationship. The event itself is irrelevant- it is the individual’s response to the event that is crucial.
Consider an individual who responds to a marital break-up with, ‘My wife has left me for another man as she thinks I’m a jerk, and everything recently just confirms what a hopeless human being I am.’ Contrast this with somebody who says, ‘My wife-what a jerk-has left me. Great. I can get on with life again.’ The chance of developing depression is greater for the first respondent than the second. This is because the event differed in terms of its impact on each individual’s self-esteem levels or because they ‘processed’ the event differently as a result of their differing personalities.
Stressful events can be acute (a marital break-up) or ongoing (a dysfunctional marriage), but both have an impact on an individual’s self-esteem.
Many people who develop a non-melancholic disorder have such a low ongoing self-image, or their personality type is such, that any stressful event is likely to trigger depression. In a sense, some people actually create their own triggers. For example, a woman who thinks that everyone rejects her may misinterpret a remark at a party and become immediately and distinctly depressed.