The Nature of Depression: Symptoms, Types and Psychological Theories

Depression is so common that some now speak of it as a modern epidemic. And yet, despite this, a huge amount of ignorance persists. Even today, many people fortunate enough not to suffer with this illness label those who do as weak and self-indulgent. Some go further, dismissing depression as a fad: something people read about in magazines and then convince themselves they have it. Even those who acknowledge the reality of depression still seem to believe that the victim can “snap out of it” by a sheer act of will.


It is interesting to note that physicians and even philosophers have been aware of depression for centuries. As early as the fourth-century BC, the Greek writer Hippocrates was describing the symptoms and even distinguishing mania from melancholia. And in 1621, the English writer Robert Burton published one of the first classic works on depression, The Anatomy of Melancholia, in which he recognized depression as “a serious ailment” (rather than the result of demonic possession, as some still believed).

Modern psychologists, though they often disagree on causes and treatments, generally do agree on symptoms. One of the most important is a loss of interest in things that normally thrill and delight you. Imagine you wake one morning, pour yourself a cup of coffee and stand before something you love – a precious painting maybe, or a classic car you have restored. Instead of the normal shiver of pleasure, you feel numb, empty and bored. The same may be true of activities you once enjoyed, like walking in the countryside or playing the guitar. Depression often leads to a kind of frozen, numb feeling. People say that, when in the grips of a severe bout, simply getting out of bed and taking a shower demands enormous effort and self-discipline. The belief that those who love you would be better off if you were no longer around is another common symptom. Depressed people also find their thoughts revolve continually around death – when it will happen, what it will be like, and so on. Feelings of guilt and worthlessness are common as well.

Different Types of Depression

Major depression, also known as clinical depression, is the most common form, affecting around seven to 10% of the American population at some point. It can strike only once in the course of an individual life, or it can return several times a year, every year. People with major depression will have most of the symptoms described above.

Next, there is manic depression, known today as bipolar disorder. Manic depressives tend to experience a wide range of moods and will often be described as volatile or unpredictable by their friends. The symptoms of major depression alternate with bouts of mania during which the opposite symptoms will be experienced. In a manic phase, the individual will have tremendous energy and enthusiasm and will often complain that their friends are not keeping up. They may act impulsively – blowing their savings on a car, for example, or beginning an affair. In extreme cases, people in the grips of mania may believe they have been chosen to fulfil a special task. This bout of mania can be swiftly followed by paralyzing depression, however, during which energy disappears and their mood plummets.

SAD, or seasonal affective disorder, is another common form of depression. People with SAD are highly sensitive to the changing seasons, especially the diminished natural light. Obviously, this is more of a problem in a country like Sweden or Iceland than Mexico. Of all the forms of depression, SAD is most easy to treat. If someone cannot move to a sunnier climate for the winter, light boxes are very effective.

Then there is agitated depression. Those who experience agitated depression find that, alongside the usual low mood and feelings of worthlessness and despair, their nervous system goes into overdrive. Anxiety is common in those who suffer from depression, but in agitated depression the anxiety is heightened and blends with the depression to produce a sense of fear and a feeling that something dreadful is about to happen. Those with agitated depression may find that they cannot sit still or stop talking. They also tend to develop some infuriating habit, like scratching their head or arm until it becomes sore, or pulling their hair and pacing the room.

Biological Theories of Depression

Some focus on the biological causes, others on the social or cultural causes. The biological explanations can be extraordinarily complex, ranging from the balance of electrolytes to the possible involvement of neuroenzymes. Two of the best known of these biological explanations involve genetics and neurotransmitters. Early optimism about the human genome project seems to have faded, and no single ‘depression gene’ has yet been identified. However, studies on twins and adopted children do suggest that genetics plays a central role in bipolar depression. One popular view, known as the stress diathesis theory, is that certain people find stress harder to deal with than others, and that this weakness may be inherited – i.e. genetic. If they then go on to experience a stressful life, it may in turn trigger a bout of depression.

The neurotransmitter theory has been around for longer than people realize. Even in the mid-1960s, it was suggested that a lack of the neurotransmitter norepinephrine could be at the root of some depressive disorders. Today, many more neurotransmitters have been identified, including serotonin, dopamine, epinephrine and acetylcholine. Popular antidepressants boost the levels of these neurotransmitters. Critics dismiss this approach as far too reductive and are hostile to the view of a depressed individual as a machine to be fixed with a tablet. Others suggest that any benefit derived from such medication is nothing more than a placebo effect: people expect to feel better, and so they do.

Psychobehavioral Theories

Other researchers emphasize the experiences people undergo and the decisions they take. Martin Seligman, for example, developed the theory of learned helplessness. According to him, when animals find themselves unable to escape pain and suffering they become unresponsive or “helpless.” Seligman suggested that something similar happens during the onset of depression: when someone feels they can no longer do anything to improve their unpleasant life, they feel hopeless and drift into a numb passivity. It has been suggested that such a pattern may in turn affect the body’s hormones and neurotransmitters, thus triggering depression.

The psychiatrist Aaron Beck focussed on the relationship between thought patterns and low mood. In essence, Beck argued that thought and depression can form a sort of vicious circle, with each feeding into the other. People develop negative, harmful beliefs (that they are inadequate and unworthy, that the Universe is a malignant place, that the future is going to be even worse than the present, and so on) which lead to depression, and this depression in turn clouds their mind and influences their thoughts, making these thoughts bleaker and darker than ever, which in turn deepens their depression. People in the grips of depression also tend to generalize and exaggerate. For example, they walk to the shops and see a group of teenagers hanging around on the corner. One of these teens yells abuse at them or starts a fight. Instead of dismissing it as a nasty, one-off incident, the depressed person convinces himself that the whole neighborhood is in the grips of a crime wave and is becoming a dangerous place to live.

Whatever the explanations, depression should never be underestimated. It can wreck careers, end relationships and trigger addictions. It is both dreadful for those who endure it and for those who love them. But treatments do seem to be improving all the time. For example, one exciting new area of research involves the use of virtual reality systems. More is also known about the positive impact a healthy diet can make, and also the negative effect of sugar, caffeine, and junk food. The frequency of the illness and the terrible effect it has, not only on the individual and his family but on the wider society, has encouraged a great deal of work – something that will certainly lead to even more effective treatments in the future.

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