Decompensation

Psychological decompensation
In psychiatry, decompensation is the deterioration of mental health in a patient with previously well managed psychological problems, leading to a diminished ability to think and carry on daily activities.

In psychoanalysis it refers particularly to the failure of the defence mechanisms and subsequent worsening of symptoms.

Physical decompensation
Decompensation is the functional deterioration of a previously working structure or system. Decompensation may occur due to fatigue, stress, illness, or old age. When a system is "compensated", it is able to function despite stressors or defects. Decompensation describes an inability to compensate for these deficiencies. It is a general term commonly used in medicine to describe a variety of situations.

For example, cardiac decompensation may refer to the failure of the heart to maintain adequate blood circulation, after long-standing (previously compensated) vascular disease (see heart failure). It may also show other signs such as poor feeding, dyspnoea, hepatomegaly, engorged neck veins and increase in pulse rate.