i) The many meanings of "depression"

One of the most common mental health problems that you can get after a brain injury is a condition called depression.

"Depression" is a very tricky word because it has different meanings.

"Depression" can describe a symptom - I feel depressed.

"Depression" can also be part of an illness a person can; for example, with schizophrenia have depressive symptoms.

"Depression" is also used by psychiatrists and psychologists as a description of an illness - a depressive illness.

These many uses of the word "depression" can be confusing.

If I say - Oh I feel depressed todaythat does not necessarily mean I have a depressive illness.

It is usually the job of the psychiatrist or psychologist to make the diagnosis of a depressive illness.

Image: The Starry NightVincent van Gogh 1889

ii) Depressive illnesses

When psychiatrists talk about depression they use a number of different words to describe different types of depressive illnesses but the common ones that a psychiatrist might talk about are:

• a major depression
• a minor depressive illness.

Psychiatrists use these terms to try to communicate to other doctors or health professionals what we mean as psychiatrists. The types of treatments we might use are also often influenced by the type of diagnosis a person has.

Depression can be a reaction to a situation.

For example: our boyfriend leaves us or someone who we really care about dies, and we might develop a depressive reaction.

Depression however can also be a biochemical imbalance.

There are particular chemicals in the brain that are important for our mood. If we get a disturbance in that balance of chemicals we can develop a depressive illness.

iii) Depression and brain injury

Often depression that people get after a brain injury is a combination of chemical/biological changes and a reaction to the person’s new situation.

We know that depression is a lot more common after a brain injury. Studies estimate that up to one third of people suffer from depression following brain injury.

Depression is common in the community - about 1 in every 10 people will at some stage get a depressive illness.

If you have a brain injury your risk for depression increases by about 2 to 3 times that of the community rate. Therefore a lot of people who have had a brain injury are going to, at some time, develop a depressive illness and they are going to need treatment.

The earlier after the brain injury a person develops depression the more likely it is going to be due to a disturbance of chemicals in the brain which has happened as a result of the brain injury.

Depression is probably one of the most common types of mental health problems that someone will have after a brain injury.

iv) Depression due to a chemical imbalance

If the mental health problem, the depression, is due to a chemical imbalance it is often going to start fairly early.

The typical picture you see is someone has:

• emerged from posttraumatic amnesia (the confused state that follows waking from unconsciousness)
• they are now starting to remember things
• they are having their rehabilitation
• they are going along quite well

Within a few weeks they start to get very depressed, they become much more negative, they do not think they are going to get better.

Sometimes they will find that they have problems with sleeping, their appetite will change, they might lose weight, they become more teary than they were, and they will really slow down in everything that they do.

While they are getting better in the general recovery from their brain injury they seem to be getting worse in their mood - and that is often because they have this chemical imbalance, they have a major depression.

v) Reactive depression

The reactive type of depression after brain injury tends to happen much later. Usually around the two year mark.

If you have had a brain injury you will be aware that most of the time the doctors will say to you that we cannot say how well you are going to get or how much of a recovery you have had until about two years after your brain injury.

The two year mark after brain injury has been determined by rehabilitation specialists because research shows this is the time by when most of the recovery happens.

In the first two years there is ongoing recovery of brain function. It does not mean people do not get better after the two year mark it is just that the rate of recovery is slower. We do not notice the changes as much. A lot of the recovery that happens after two years tends to be an adaption to the changes from the brain injury.

In many patients with a reactive depression what has happened is that they have gone along and they have thought - oh the two years are not here yet I will keep getting better, I will keep getting better - and come the two year mark they have still some problems and they get very depressed and very sad.

What they are doing is they are mourning or grieving for the loss of the person that they were and the things that they cannot do any more and struggling with. Whenever anyone loses something important to them they can feel grief. When someone loses who they are, what they can do, or even someone very close to them people can get depressed for a period of time.

Sometimes the reactive depression can be so severe that it causes a biochemical imbalance in the brain.