Demarcation of the disease depression
Lars Kessing, Professor of Psychiatry
Even though your doctor knows that you have a disorder of the serotonin system in the brain, when you are suffering from depression, the doctor can't measure this disorder with a blood test for example or arrive at your diagnosis in this way.
The doctor arrives at the diagnosis depression by asking you questions and by examining you.
The depressive episode is called F32 in the ICD-10 system. The doctor makes this diagnosis after an examination, after which the different ICD-10 symptoms are assessed. The doctor basically follows a questionnaire which has been developed as a kind of screening test for diagnosing depressive diseases.
Figure 1 shows the depression questionnaire. According to ICD-10 the diagnosis of depression applies to the last two weeks, during which every symptom must have lasted for more than half of the time.
An important dimension in the disease depression is the severity of the symptoms. ICD-10 divides the F32 diagnosis into mild, moderate and severe, dependent on how many symptoms are present.
The depression questionnaire is a guide for making an ICD-10 diagnosis but it can never replace the assessment of a doctor. You should be aware of this if you wish to try out this questionnaire yourself. But if your score from the questionnaire is above 20, you should regard it as an indication of the need for you to see your family doctor.
Beck's Depression Inventory
Another screening instrument that has been named after the American psychiatrist Aaron Beck, who developed it on the basis of the cognitive psychotherapy model, is Beck's Depression Inventory (BDI). It has been widely used all around the world, where the effect of the cognitive psychotherapy is assessed.
Hamilton's Depression Scale
The British psychiatrist Max Hamilton has developed HAM-D, a depression scale, which amongst other things is used by the doctor in an interview with the patient, where he/she asks a number of questions about depression. The doctor can then calculate the degree of the depressive symptoms.
HAM-D is also used when the National Board of Health is assessing whether a new medicinal product should be approved for use against the depression.
Quality of life
The depression involves areas that amongst other things affect daily social functioning. Depression is distinguishable from anxiety for example in the way that it not only affects the actual interest in the daily chores but also the performance of the daily tasks that we have to do. It might be in the form of a lack of energy, less self-confidence, difficulties concentrating etc.
There is evidence to suggest that it is the positive well-being that is reduced, when a depressive disease starts. Quality of life scales have been developed which measure the degree of the positive well-being. One of them is WHO's short five point system, WHO-5, which you can try out here.
The WHO-5 questionnaire uses the following scoring: the scale becomes a kind of percentage scale from 0 (worst possible quality of life) to 100 (best possible quality of life). Studies of the general population of have shown that on average we score 75. If you score around 50 or less, you should fill out the depression questionnaire, in order to find out whether or not there are signs that point towards depression.