Educationals

Introduction

All human beings have experienced the feeling of depression at one time or another. However, a normal depressive state is not the same thing as a pathological depressive illness.

A pathological depression is a profound all pervasive disturbance in the feeling state or mood which can secondarily affect the individual's thinking and behaviour. In contrast to feelings, a mood state is prolonged over a period of time. It may or may not be triggered off by a set of circumstances. It is severe in intensity and it seldom remits without treatment.

Depression is recognised by a triad of classical symptoms or signs. The first symptom is depression of the mood. In pathalogical depression the mood is miserable, sad, sorry, suicidal and all pervasive. The patient cannot snap out of it. The second symptom is poverty of ideas. The patient complains that he cannot think, that he forgets easily. He has no self- confidence. He has gloomy pre-occupations. He visualises failure at work, in finances, in family life and in social life. The third symptom in psychomotor retardation. The patient walks and talks slowly. Everyday activities require a great deal of effort. He puts off doing things which he would otherwise do willingly and effortlessly.

Biological symptoms like a characteristic depressive insomnia during the later part of the night may also be present. The circadian rhythm may be disturbed. The patient feels worse during the early part of the day and then progressively better as the day advances. Autonomic symptoms like loss of weight, loss of appetite, loss of libido, constipation and a mildly elevated blood pressure can be present. The patient may complain of somatic symptoms e.g. vague pain for which there is no medical explanation. Some depressed patients develop psychotic symptoms like auditory hallucinations in the form of voices which condemn them or order them. There may be delusions of guilt or worthlessness or somatic delusions about body parts or their functions.

The documented association between neurological illness and depression is not of recent origin. Seventy years ago, Emil Krapelin recorded the co-existence of both elation and depression in the same patient and called it manic depressive psychosis. He observed that depression is often complicated by atherosclerotic brain disease. In 1922, Babinski noted that specific emotional states may be associated with a specific brain injury e.g. injury to the right hemisphere and the emergence of euphoria.

Depressive mood disorder and neurological disease interface in three ways: First, depression can precede a neurological disease as in dementia. Secondly, depression may accompany a neurological disease as in Parkinson's disease. Lastly, depression can follow a neurological disease as in post-stroke depression.

Over the years, depressive illnesses have been classified in various ways. A simple clinical way is to recognise two kinds of depression. One which is reactive to the disability and one which is not necessarily or exclusively reactive in origin. Many neurological disorders are associated with depression. The list includes dementia, epilepsy, Parkinson's disease, multiple sclerosis, neoplasms, cerebrovascular disorders, Huntington's chorea, Wilson's disease, brain trauma, progressive supranuclear palsy, magraine, hydrocephalus and brain infections.

Some drugs have also been reported to cause depression as a side effect. These include opiate analgesics, barbiturates, NSAIDs and anti-hypertensive drugs like reserpine, alpha methyl-dopa etc.

Depression and Dementia

Depression and anxiety are early features of Alzheimer's dementia. Although depression can be an early sign of dementia, it is not significantly more common in dementia than in age matched controls. Several studies have also shown that a true progressive dementia later develops in a high percentage of these patients who have depression as their first symptom.

Symptoms develop slowly in the demented patient. Depressive mood is not the presenting symptom. The emotions tend to be labile and superficial. The demented patient is disinterested more than dejected. Autonomic symptoms of depression like loss of appetite, loss of weight, constipation and dryness of mouth may be quite prominent. Early morning insomnia and diurnal mood swings are frequent. The demented depressive patient is very likely to demonstrate delusions of guilt, phobias or somatic and nihilistic delusions. There is a tendency to be critical and irritable. Behaviour is characterised by incapability and social withdrawal. Failure of attention, concentration, memory and drive are prominent. A varying amount of impairment of cognitive and intellectual abilities can be seen. These symptoms are variable and the patient can be persuaded to concentrate for short periods of time.