Reactive-biological depression

Major unipolar depressions reactive, biological, reactive-biological, atypical... 

The older MAOIs (e.g. phenelzine) may be more effective than other classes in atypical depression, a form of depressive illness where mood reactivity is preserved, lack of energy may be extreme and biological features are the opposite of the normal S3mdrome i.e. excess sleep and appetite with weight gain. 

In very similar ways, in numerous studies the biochemistry of people with reactive depressions has been shown to be markedly altered. For example, emotionally healthy individuals without a personal or family history of depression who encounter major psychosocial stressors (especially losses) often become depressed. Presumably such people are not especially at risk (biologically or psychologically) for depression, but nonetheless they become depressed in response to significant stressful events. Further, in the course of their reaction, some patients develop not... 

In its pure form, reactive depression can present with severe levels of symptomatology, yet basic physical functions (sleep, energy levels, and so on) are relatively unaffected. Note that many reactive depressions do take on biological features, as will be described below, but the pure reactive disorder noted here is seen without major physiological symptoms. 

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