The classification and diagnosis of mood disorders such as depression can be difficult for all sorts of reasons, one being that the behaviours outlined in the criteria for depression in ICD-10 are seen as ‘normal’ behaviours in most people. For example, a lowered mood could be seen in many people who may have just been put in an unhappy situation or have an abnormal personality and that doesn’t necessarily mean that they have a symptom of depression. This supports the idea that there are a number of problems with the classification of this disease.
Another problem with the diagnosis of depression is that the criteria for depression requires an individual to have two of the listed eight symptoms, meaning that two different individuals could both be diagnosed with depression, with completely different symptoms to each other. This is a relatively undemanding requirement, as it is such a broad criteria which would imply that the diagnosis of depression has limitations.
A third problem with the diagnosis of depression is that depression frequently occurs alongside other disorders such as substance abuse, alcoholism, eating disorders and schizophrenia, and it can be difficult to decide which is the primary disorder.
It is also hard to determine whether the mood disorder symptoms in a patient who has another medical condition are secondary to the effects on the brain of the medical condition, secondary to the effects on the brain the drugs used to treat the medical condition or reflective of a primary mood disorder unrelated to the medical condition. Therefore the diagnosis for moos disorders is made very difficult by factors such as this.
A fourth concern with the classification and diagnosis of depression is that whilst depression is a universal disorder and the symptoms are similar around the world, there are some cultural differences. The biggest is between western and non-western cultures. People from non-western cultures often present with more bodily complaints than subjective distress. This could be misinterpreted if only western-based diagnostic tools are used.
The difference between unipolar and bipolar disorder is highly relevant to the diagnosis of mood disorders such as depression as it often difficult for clinicians to differentiate between the various types of depression . A clear distinction has been made between unipolar and bipolar disorder, but there are still complications between the two. Coryell 1995, found that 10% of people diagnosed with unipolar disorder would then go on to develop bipolar episodes. As the treatments for both of these mood disorders are different, it causes more complications with the diagnosis and treatment of such disorders which is consequently a weakness in the diagnosis of depression.
Furthermore, there are types of disorders such as seasonal affective disorder (SAD) which is a type of depressive disorder which occurs during the winter months. Mood has a seasonal variation within the normal population and it has been questioned whether it is a valid separate syndrome. This is another issue when trying to diagnose and classify an illness, as to some extent seasons affect the generation as a whole.
An additional issue there is when trying to diagnose a mood disorder is that essential features of depression are similar in adults and children, but it is because children have coexisting disorders including conduct problems and disruptive behaviour that depression is often overlooked as a diagnosis. Certain depressive symptoms such as irritability are more often than not more likely to be found in children that adults. This can often be an issue when trying to diagnose a child patient, as the depressive symptoms are often overlooked which is a limitation to the diagnosis if depression.
Another issue with the diagnosis and classification of depression is the method used for the way it is diagnosed. The doctors are given a list of symptoms and have to judge how many they think the patient may have. Patients will be given a phq-9 questionnaire which brings the problem of self reporting, as some people may lie on the questionnaire or may truly believe their depression isn’t as bad as it is. They might also give socially desirable answers, leaving the GP to conclude that they are not severely depressed when they may well be. It has been suggested that about 3% of the general population are treated by their GP for depression. It has also been suggested that half of the people who go to their GP with depressive symptoms are not recognised as having depression. Overall the diagnosis of depression is very vague as the symptoms are too broad and there are obvious limitations to using a self reporting questionnaire.
An extra issue is that there are endogenous, and non- endogenous depressions. One which is caused by biological factors, and the other by cultural factors, although Hammen 1995 says there is little evidence to support this. People diagnosed with endogenous depression are more likely to suffer from more severe symptoms and a greater likelihood of suicide. This seems to have implications for therapy, with endogenous depression responding more positively to ECT and to certain antidepressant drugs.
A different issue with the diagnosis of depression is that depression occurs twice as frequently in women than it does in men. Men may be less likely to admit to symptoms of depression and are more likely to forget previous symptoms. This is a real issue when trying to diagnose an illness, as without a full understanding of the patient’s symptoms the GP cannot make an accurate diagnosis.
Above I have outlined the main issues associated with the classification and diagnosis of depression and have shown why it is so hard to differentiate between different disorders.
