1. The different types of mood disorders
The Black Dog Institute believes there are 3 broadly different types of depression:
• Non‐melancholic depression
• Melancholic depression &
• Psychotic depression
And there are 2 types of bipolar disorder:
Type 1 &
Type 2
Depression can be a ‘normal’ mood state (like feeling sad), a severe reaction to a difficult or stressful situation, or a disease state (such as melancholic, psychotic or bipolar depression).

2. Let’s look at melancholic depression first.
This is often known as biological depression as its causes are primarily physiological – caused by biochemical imbalances in the brain.
Its defining features are:
• a severe depressed mood state; &
• psychomotor disturbance – usually showing as: slowed speech, agitated physical movements & slowed cognitive abilities or thought processes.
Melancholic depression is a relatively uncommon type of depression.

3. Melancholic depression is often hereditary & can run in the family.

4. Psychotic depression is the least common type of depression.
The defining features of psychotic depression are:
an even more severely depressed mood state
more severe psychomotor disturbance, &
psychotic symptoms – either delusions (false beliefs) or hallucinations (false sensations), with delusions being more common; & strong feelings of guilt.

5. Non‐melancholic depression is the most common of the 3 types of depression.
Non‐melancholic essentially means that the depression is not primarily biological. Instead, it has to do with psycho-social causes, very often linked to stressful life events &/or the individual’s personality styles.
It can be hard to accurately diagnose because it lacks the defining characteristics of the other two depressive types (namely psychomotor disturbance or psychotic features), &
People with non‐melancholic depression can usually be cheered up to some degree.