Self-reinforcement

A lot of the thoughts, feelings and behaviours, which occur as part of depression, can also contribute to prolonging and strengthening the course of the depression, and hence have a self-perpetuating effect.

Feelings and memory
If you feel down, it can affect your memory in a way that only makes you think of negative rather than positive memories. You might, for example, feel that your whole life has been dreadful even though that isn’t true. In trials, where healthy trial subjects were made to feel depressed through hypnosis and chemical substances, it has been proven that the feelings distort the memory. The trial subjects, who were made depressed "artificially", remembered their past in a more negative way than they did a few hours earlier, when they were in their normal mood.

Behavioural change
If you are depressed, your behaviour often changes and this affects your relationships.
Your negative behaviour towards others also causes them to react negatively towards you. This is of course a problem, as they distance themselves from you instead of comforting and encouraging you. You become more isolated and miserable and you slide deeper into depression.

Vicious circles
These two circumstances create a self-perpetiating "vicious circle" of negative thoughts and feelings and negative relationships with others. This eventually creates two vicious circles, one inner and one outer circle.

The inner vicious circle is the negative thoughts about life, which constantly prevails as a thought pattern in you and which makes you vulnerable. During periods of adversity, the inner vicious circle causes you to feel severely depressed. This dejection increases your negative thoughts, your negative thoughts increase the dejection and so it continues.

The outer vicious circle increases your tendency to react passively or negatively towards others. Your push the people closest to you away from you, which means that you become isolated and lonely, and ultimately more depressed.

Cognitive therapy
Cognitive behavioural therapy is a form of psychotherapy which focuses on analyzing and changing inappropriate patterns of thought and behaviour. This form of therapy is a very effective psychological treatment method for depressions.