Depression is a continued state of lowered mood. This can be mild, leaving a person feeling 'down' and that everything is hard to do; through to severe, causing so much distress that they give up the will to live.

Depressive illness drains energy, affects sleep quality and can cause loss of appetite - the very things that enable our bodies to function properly.  Also, a person can feel detached from their surroundings. 

Such disorders occur in all people and at all ages.  Some believe that the increase of stress in our lives has caused a dramatic rise in the condition.  As yet, there is no evidence to prove this.

Depression may be triggered by one or several factors such as chemical imbalances in the brain, low blood sugar, tension, environmental and life stress, lifestyle problems and illness.

Depression affects body and mind

There is a complicated interaction between the physical (body) and non-physical (mind).  This relationship must be maintained on many different levels for the benefit of both systems.  Any imbalance will adversely affect the other: mental problems can cause physical symptoms, and physical symptoms can cause an imbalance in the mind.

The mood chemicals

The brain has many natural chemicals affecting mood.  The two most important as far as depression is concerned are serotonin and noradrenaline - known as neurotransmitters.

Working correctly, these produce a feeling of wellbeing and contentment.  They are metabolised by an enzyme called monoamine oxidase.

For people who do not produce enough serotonin and noradrenaline, the enzyme destroys available resources, leading to depression.

Types of depression

Endogenous depression

This traditional description of depression implies generation of illness from within the brain.  Endogenous depression is also known as organic or chemical depression, and is caused by, for instance, the menopause, infections, glandular disorders, injury and stress.

Reactive depression

This is usually of moderate severity.  A person may be able to identify a particular event that has caused depression as a reaction.

Unipolar depression

When the condition is described as unipolar, an individual's mood swings from normal to depressed.  When the end of the depressive illness is reached (naturally, or by result of successful treatment) a normal mood returns.

More commonly known as major depression, unipolar depression can be reactive or endogenous.  It is the most common type of depressive illness and can occur once or recurrently.

Bipolar disorder

Bipolar disorder affects approximately 1 in 10 depression sufferers.
Often referred to as manic depression, bipolar disorder involves a cycle of severe depression interspersed with periods of hypomania.  When recovery occurs, the sufferer goes past their normal state of mind and enters one of extreme elevation or agitation. 

The frequency of episodes and pattern of relapses is variable - though remissions tend to get shorter as time passes.  The depression cycle becomes more common and lasts longer after middle age.

Doctors do not fully understand the mechanism of bipolar disorder, although a variety of genetic, biological and environmental factors appears to be involved in triggering episodes of illness.

Seasonal Affective Disorder (SAD)

It is common to eat and sleep more during the winter months.  People feel deflated when dark mornings and short days signal the onset of the season.  For some, these feelings become severe and cause considerable disruption to daily life.

This condition, known as Seasonal Affective Disorder (SAD), stems from the lack of sunlight available in winter.  Researchers have shown that sunlight affects brain chemistry.  There are many different theories as to why this happens.  SAD is often treated using natural light or light-box therapy to stimulate the chemicals in the brain.
People suffering from SAD frequently oversleep and do not feel refreshed when they get up in the morning.  They often crave carbohydrate-rich food, leading to weight gain.  Health problems such as low immunity, lethargy and depression are all characteristics of SAD.

Approximately 2% of people in northern Europe suffer from SAD, with around 10% coping with milder symptoms (sub-syndromal SAD, or winter blues).  SAD is not a psychosomatic or imaginary illness.  People worried about SAD are advised to seek further help from their GP.

Anxiety

Anxiety should not be considered as a symptom of depression, though it may coexist with it.

Anxiety can be felt as panic or fear, typically out of proportion to the original problem.  The person suffering from anxiety cannot breathe properly and may describe a squeezing sensation around their chest.  They may also feel sick and dizzy, seriously ill, and in great danger.  These feelings are a natural reaction to our body going into over-drive.  For some sufferers, feelings of anxiety are so severe that they cannot leave the house or lead normal lives.  A vicious circle then forms between symptoms of anxiety and depression.

Body chemistry affects the mind in many ways.  For example, if we are frightened, we produce adrenaline, the body's protection hormone that causes what is known as the fight-or-flight reaction.  If adrenaline is not used up in physical activity, the musculature of our bodies tenses.  Other hormones and neurotransmitters affect our emotions.  If these are unbalanced, we can become ill and suffer from anxiety in the same way that we can suffer from depression.

03/06/2009