Major depressive disorder is divided into various different clinical subtypes each of which has its own features. To an extent the classification system still relies on some fairly arbitrary decisions about symptoms. Moreover, some of the subtypes can seem a little difficult to distinguish and there is some speculation as to whether there is value in doing so, particularly as most treatment tends to be rather general in application. Even so, subtypes of depression have been identified and some approaches to treatment take these differences into account.
Dysthymic disorder - is a milder but more chronic form of major depressive disorder. A diagnosis is reached by the person having had a depressed mood for at least two years and having at least two additional symptoms from the list for major depressive disorder.
Depression with Melancholic Features - is generally considered to have a purely biological basis. The main characteristic is the person’s clear inability to experience any pleasure. In fact so many of the symptoms are shared with major depression that clinicians may struggle to find a distinction. Other symptoms must include at least three of the following:
- Depressed mood that is regularly worse in the morning.
- Early waking.
- Significant weight loss or signs of anorexia.
- Clear signs of agitation.
- Excessive or inappropriate guilt.
Depression with Atypical Features - refers to symptoms in which the person can experience positive reactions to positive events but where at least two of the following features are also present:
- Weight gain and/or increased appetite.
- Prolonged duration of sleep (10 hours or more per day).
- Sensation of heaviness in the limbs.
- Over-sensitivity to interpersonal rejection.
Depression with Psychotic Features - refers to symptoms of depression combined with the psychotic features of delusions and hallucinations.
Depression with Catatonic Features - catatonic features refers to excessive physical movement that has no particular focus. Alternatively the person may show signs of inactivity to the extent they may remain still for lengthy periods of time and maintain postures they are placed in.
Depression with Postpartum Features - better known as post-natal depression. Even more common however are postpartum blues which affect around 30 percent of women. Symptoms of postpartum blues include rapidly changing moods and crying. Postpartum depression meets the full criteria for depression and must occur within four weeks of childbirth.
Depression with Seasonal Onset - formerly known as seasonal affective disorder or SAD, this subtype of depression has onset periods between October and February in the northern hemisphere, when daylight hours are shortest.