Heart disease and depression

Most people understandably are very shocked if they get hit by a serious disease. This is no less true if it is a disease which hits such a vital and central organ like the heart, and it is therefore normal to suffer a crisis in such a situation.

However, a crisis is a condition which will pass relatively quickly, after which we learn to adjust to the new circumstances. Most people have the strength to adjust to new situations, and some of us even grow and become wiser as a result of the crisis.

But what happens when the crisis, instead of just passing by, continues on and on and develops into depression? The crisis then no longer causes us to develop and become stronger and wiser. Instead we get into a negative spiral, which pulls us into a chronic depressive condition that swallows both our strength and drive.

Depression is common amongst heart patients

Our culture has widely accepted that patients become depressed in connection with physical illness. Depression is very common amongst patients who suffer from heart disease, and it is therefore often regarded as a normal reaction.

Studies indicate that approximately 20% of the patients who are admitted with ischaemic heart disease develop severe depression, whilst up to 30% suffer mild depression after their discharge. The figure is similar for out-patients with ischaemic heart disease (heart disease with a lack of oxygen in the heart). And research data indicate that depression in this group of patients often isn't treated and generally is underdiagnosed, i.e. it goes undetected.

In the last 10-15 years the number of research results which link depression and ischaemic heart disease has increased significantly. Depression has been identified both as a risk factor for developing ischaemic heart disease and as a risk factor in the course of the heart disease. It was found that heart patients with depression have a higher death rate than heart patients who don't suffer from depression. Depression is therefore a disease which must also be treated in heart patients.

Increases the death-rate

The last 10 years' research indicates that depression in patients with ischaemic heart disease increases the death rate by 3-4 fold. Depressed heart patients therefore die 3-4 times as frequently as those patients who don't show any signs of depression during the first six months after the heart disease has been diagnosed.

This increase is not limited to severe depressions but also occurs in heart patients with mild depressions. Research has shown that the negative effect that depression has on ischaemic heart disease is just as great as the effect from other negative factors like smoking and high blood pressure, the degree of sclerosis and the effect of the heart's ability to pump effectively.

Other tests show a similar negative effect of depression after a cerebral thrombosis. Tests even indicate that being a little psychologically weak and vulnerable - without being depressed as such - can also make you susceptible to developing ischaemic heart disease and cerebral thrombosis.

The connection is not completely clear

The biological links that can explain the connection between depression and ischaemic heart disease have not been fully explained, but research data indicate several possible biological mechanisms. Amongst the factors that are central to the development of the disease in the combination of depression and ischaemic heart disease are:

• increased activity in the sympathetic nervous system
• reduced variation in the heart's ability to vary the speed and power with which it beats
• activation of the blood platelets so they form blood clots more easily

The hypothesis that depression causes an increased activity of the blood platelets is central to the connection between depression and death after ischaemic heart disease. The depression's effect on the risk of dying after ischaemic heart disease should supposedly be seen in the light of the strain that the body is exposed to due to stress. To be suffering from heart disease and depression simultaneously must be one of the most stressful situations that a person can be in. If we look at the effect that stress can have on the body of a normal and healthy person, we can begin to imagine why it can be distinctly dangerous for a heart patient to be suffering from stress caused by depression.

The effects of stress

The human stress response - i.e. our reaction to stressful influences - is primarily adapted to a life in a world which looked completely different to the way it looks today. We lived in a world, where the ability to react physically quickly and effectively was of vital importance in order to avoid getting killed. It was furthermore a prerequisite for being able to hunt and provide one's living.

Several thousand years later, it is the same reaction that occurs when a person becomes stressed:

• The production of adrenaline increases in order for us to react quickly
• The free fatty acids in the blood increase, in order for us to have more "fuel" available
• The blood pressure rises
• The heart beats faster and at maximum force, in order for us to be able to perform physically
• The blood platelets are activated and prepare themselves for repairing possible damage

The great problem today, however, is that we neither go hunting nor find ourselves in battle situations. We are probably lying in a hospital bed or pottering about at home and waiting to become well, and the body's reaction is therefore completely inappropriate. This is probably the reason why depression and the increased stress level it causes have such negative consequences for the heart patient.

Knowledge is important

Depression in itself is a very unpleasant disease with dramatic consequences for the quality of life for both the patient and his or her family. But depression also increases the costs of the health service and furthermore affects the patients' ability to follow the doctor's instructions both in connection with taking the prescribed medicine and in connection with recommended life changes, e.g. food habits, stopping smoking and exercise. Depression is therefore not only something that concerns psychiatrists.

All the consequences that occur as a result of depression and anxiety in heart patients are quite serious. It is therefore also important to communicate this knowledge to other parts of the health service, in order for the psychological complications to be identified and treated - first and foremost to the heart specialists, who of course are the ones seeing these patients.