Mental Health Care

Until a few years ago, researchers believed that depression could be of two kinds: endogenous, caused by inexplicable sense of gloom; and exogenous, caused by reverses in life. That theory is no longer accepted. The current consensus is that only those people who suffer from certain biological and psychological vulnerabilities are prone to depression. Stressful life events can act as precipitating factors only. This theory explains why some people become depressed even when things are going well with them, and why others take even the most adverse circumstance in their stride and remain unaffected by it.

Biological factors

Functional imaging studies have shown that certain chemicals in the brain which act as transmitters in the brain circuit may play an important role in regulating human mood and emotions. The most significant of these are norepinephrine and serotonin.

The norepinephrine link. There is now considerable experimental evidence that a deficiency of norepinephrine in certain brain circuits leads to depression, while its overabundance generates mania. A whole, intricate mechanism has been discovered explaining how it works. The circuits that feel either paucity or abundance of norepinephrine originate in the brain stem, primarily in a region called the pigmented locus coetuleus. These circuits extend to many areas of the brain, including the limbic system, which play a significant part in regulating emotions.

Serotonin connections. Serotonin has taken the centre stage in research on the causative factors of depression, ever since the newer antidepressants that change serotonin levels have met with good therapeutic success. The view is that a deficiency of serotonin at the serotonin-using synaptic junctions in the brain circuit can upset the mood and emotions by promoting, or permitting, a fall in norepinephrine levels. The anatomical basis to this finding has also been outlined.

There may also be other mechanisms at work. Serotonin depletion might affect many brain regions that participate in depressive symptoms-including the amygdala (an area involved in emotions), the hypothalamus (involved in appetite, libido and sleep) and cortical areas that participate in cognition and other higher processes.

The most clinching evidence to the serotonin theory comes from these medications, called the selective serotonin reuptake inhibitors SSRIs), that have revolutionized the treatment. They are highly effective and produce milder side effects than older medications.

Hormonal abnormalities. Depressed people have an imbalance of hormones, possibly fuelled by a chronic activation of the hypothalamic-pituitary-adrenal axis-the system that manages the body’s response to stress. They generally have higher than normal levels of corticotropin-releasing factor, ACTH, and cortisol, and this may affect the mood. In addition, depression has also been linked to both a deficient or overactive thyroid gland.

Role of other organic disorders. A variety of organic conditions have a link with depression. Deficiencies of vitamin B6, vitamin B12, and folic acid; degenerative neurological disorders, such as Alzheimer’s disease and Huntington’s chorea; strokes in the frontal part of the brain, and certain viral infections are some of them.

Medication as the culprit. A variety of medications, which include those given for pain relief, some antibiotics and anti-fungals, blood pressure lowering medicines, steroids, oral contraceptives, anti-ulcer drugs, and several others may also cause depression in some cases.

Genetic Factors

Both depression and bipolar disorder are known to run in families. The evidence for heredity is much stronger for bipolar illness than for unipolar depressive illness. If a parent has bipolar disorder, there is a 27 per cent chance that his or her child will have a mood disorder. The risk goes up to 50 to 75 per cent if both parents suffer from the illness.

The role of genetic factors in the genesis of depression also finds corroboration in twin-studies. Genetically identical twins, raised in the same environment, are likely to suffer from depression three times more than the non-identical twins who only have about half of the genes in common. Adoption studies also support this theory. These studies show that children of depressed parents are vulnerable to depression even when raised by adoptive parents. On the other hand, children of healthy parents fostered by. depressed adoptive parents need not suffer depression.

Psychological Factors

Stressful life events and depression. Stressful life experiences may play a significant role in the genesis of depression. According to reliable data, the loss of a parent before age 11 is the most significant event associated with the development of depression in later years. The loss of a spouse or some other loved one is also a common environmental stressor that may trigger depression. Other stressful experiences include divorce, pregnancy, the loss of a job, and even childbirth. Many women experience a postpartum depression, after delivering a baby. The transition from one stage in life to the next, such as adolescence, adulthood, middle age and old age, also puts individuals at an increased risk of depression. Women in particular are at risk in middle life, when the children leave home to make their separate existences. Likewise, retirement is another such time, especially for people who derive satisfaction, status, or esteem from their jobs. Serious physical illnesses or disabilities can also be a real burden for some and lead to depression.

Personality factors. All humans, of whatever personality pattern, can and do get depressed, but people with depressive personality traits appear to be more vulnerable. Depressive personality traits include gloominess, pessimism, introversion, self-criticism, excessive scepticism and criticism of others, deep feelings of inadequacy, and excessive brooding and worrying. In addition, people who regularly behave in dependent, hostile, and impulsive ways also appear to run a greater risk of this illness.

Psychoanalytic links. Sigmund Freud believed that depression was a psychological response to loss-either real loss, such as the death of a parent or spouse, or symbolic loss, such as the failure in achieving an important goal. Freud believed that a person’s unconscious anger over such loss leads to a weakening of the ego and the loss of energy.

Theory of ‘learned helplessness’. When animals were exposed during experimental work to repeated electric shocks from which they could not escape, they soon developed an attitude of helpless resignation and made no attempt to escape from future shocks. Basing on these experiments, psychologists have proposed that human beings, when exposed to uncontrollable and inescapable events for long, also develop a similar attitude of ‘learned helplessness’-that, one cannot control the outcome of events. This leads to apathy, pessimism and loss of motivation-the characteristic symptoms of depression.

Cognitive theory. Some people habitually tend to focus only on the negative aspects of any given situation; they interpret facts in negative ways and blame themselves for all misfortunes. This is a negative, self-defeating attitude which often takes roots in early childhood. It makes situations seem much worse than they really are and increases the risk of depression, especially in stressful situations.

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