Is depression a physical illness or a psychological disorder?
This is not a useful question when you are treating depression because it is both. Anything you think or feel has a physical event in your brain that causes it; a change in chemical balance, a firing off of some nerve cells, a surge of a hormone or a transmitter. Changes like these, if they lead to feeling depressed, can be caused by very normal life experiences, such as a loss.
The physical change underlying the psychological feeling is not necessarily anything that could be called an illness because it is how your brain is supposed to function, but if the change in mood is big enough, you can feel so depressed that you can rightly describe it as a depressive illness and you definitely need treatment. Your brain can be functioning normally but you have a psychological illness.
How we describe these moods depends on how we understand what is happening to us. Grief is regarded as a normal reaction to loss and not generally considered an illness, but grief can have exactly the same symptoms as depression and if you feel like grief but without knowing why it is treated as an illness.
In some people, the normal system for stabilising your mood may not function properly. It seems that, rather like your temperature or your appetite and thirst and many other regulatory processes in your body, there is a mechanism (not properly understood) which keeps your mood within normal limits. If that mechanism doesn’t work well, you may get swings in mood for no apparent reason, which don’t correct themselves. Those swings can be up – in which case you are described as manic – or down – in which case you are depressed. In these cases, referred to as bipolar disorders, it is right to think of depression as a physical illness, even if there was a clear trigger for the mood swing.
There are also theories about depression being caused by inflammation of the brain. One such theory is that gum disease can infiltrate through the roof of your mouth and cause inflammation. Other infections may do the same. These are possibly very important causes of depression in some people but they are not convincingly proven.
Physical treatment for depression
There have been a lot of different ways of treating depression, ranging from various kinds of torture, with the idea of driving out demons, to more well-meaning shocks to the system such as causing epileptic fits by injecting insulin or giving electric shocks to the brain (electro convulsive therapy; ECT). ECT is still used for treating depression and seems to work well for some patients although relapse is common when treatment stops and patients describe losing chunks of memory. Antidepressant drugs are widely prescribed these days instead.
Nobody really knows how antidepressants work and the evidence that they do work is a bit controversial. Their effectiveness in treating depression is most convincing when used to treat very severe depression, for example when patients have such an extreme low mood that they also get delusions that they are, for example, wicked or physically ill, or they may get hallucinatory voices criticising them. These are very severe and unusual cases.
There is little evidence that antidepressants help with treating mild depression; depression at a level which causes a lack of energy, tiredness, anxiety and comfort eating. Even moderately severe depression which causes symptoms such as early waking, marked lethargy, feeling worse in the mornings, loss of appetite and loss of enjoyment may not be helped significantly by antidepressants. In mild and moderate depression, antidepressants may actually make life more difficult by causing side effects on top of the symptoms of depression.
Antidepressants seem to need a few days, even a fortnight, to start to work in treating depression. So for a fortnight, patients get side effects while still being depressed. Side effects can include sedation, constipation, effects on vision, difficulty having an orgasm, low blood pressure and weight gain. Side effects usually recede after a while but the effectiveness of the same dose of antidepressant may recede at the same time so the dose has to be increased to remain effective.
Unfortunately, few GPs have the level of experience of treating depression to do it well. Inexperienced doctors tend to prescribe too low a dose to be effective and continue too long so that the patient gets withdrawal symptoms when they stop, without getting any antidepressant benefit.
The conclusion, therefore, is that antidepressants can be as much of a problem as they are a solution. They are really only good for severe depression and are probably not a good treatment for mild to moderate depression.
Psychological treatment for depression
Cognitive Behavioural Therapy (CBT) is the treatment of choice for mild and moderate depression. The aim of CBT is to help the patient learn how to think in ways that make depression better and avoid thinking in ways that make it worse. This involves:
- Teaching about how thoughts affect mood
- Learning to spot thoughts and situations that are depressing
- Learning to substitute thoughts that are comforting or uplifting
- Doing things that make you feel better
- Stopping doing things that make you feel worse
Patients keep diaries and records to help them concentrate and pay attention to their thoughts and how they feel and are given homework to practise in between appointments.
The beauty of CBT is that, unlike antidepressants, it has no harmful side effects (other than having to make the effort to do it), no withdrawal symptoms and no risk of relapse when it stops. In fact it teaches skills which can help prevent relapse.
Unfortunately, to be effective, therapists need to know what they are doing and that requires training and supervision. It takes time to train a CBT therapist and the therapy itself requires time. The result of all this is that CBT is expensive in time and money, leading to waiting lists and delays before treatment.
By contrast, prescribing an antidepressant is immediate, easy and relatively cheap. Even if it is of no benefit in treating depression it can feel like you are at least doing something. GPs faced with a patient who is desperate for help are bound to be tempted to prescribe an antidepressant even though they may know that it’s unlikely to be effective. Consequently, although we know that antidepressants may do more harm than good for patients with mild or moderate depression, they still get prescribed as the first choice of treatment.
Recovery from depression
Usually depression will get better on its own. This may be because circumstances change and the cause of depression goes away. It may be because the way the brain regulates itself means that it settles back to its normal mood spontaneously and things that seemed depressing just start to look better.
Nevertheless, living with depression is horrible, both for patients and for those around them. On average, depression lasts about 6 months and getting CBT within that time may be difficult. However, people who have been depressed once, are more likely than the rest of the population to get depressed again. For this reason it is very useful for anyone who has been depressed to have a course of CBT so that they learn the techniques for dealing with depressing ways of thinking in case it happens again. Treating depression with CBT can help prevent relapse.
