Feeling sad or down on occasion is a normal part of life for all people and in most instances periods of sadness are relatively temporary. These states are a normal part of our human emotional profile and temporary mood fluctuations reflect the natural rhythms of emotional functioning.

People with Clinical depression or Major Depressive Disorder, however, experience depressed mood or a loss of interest or pleasure (Anhedonia) in most activities for a minimum of two weeks. This low mood or loss of interest and pleasure is not a temporary state and is experienced nearly every day for most of the day. For clinical depression to be present at least one of the above symptoms is accompanied by at least 4 of the following symptoms:

 

Each of the above symptoms needs to be present nearly every day for most of the day. In addition to the above symptoms, those with clinical depression suffer from a number of associated difficulties that significantly impair social and occupational functioning. Those with depression may report feeling more irritable or angry, a pervasive sense of helplessness or hopelessness, increased levels of anxiety or worry. Recurrent panic attacks may also be present.

People suffering from depression often report sinking feelings in the chest or heavy bodily feelings. They can also experience most physical symptoms of anxiety, some of which include tension, nausea, gastrointestinal upset, diarrhea; or they may experience panic attack symptoms.

 

To experience a full panic attack people must have four or more of the following symptoms: rapid heart rate, shortness of breath or difficulties breathing, dizziness, blurred vision, shaking, nausea, choking sensations, sweating, hot flushes or chills, numbness or tingling sensations, chest pain or discomfort, derealisation (feeling as if the world is unreal), depersonalisation (feeling outside one's body) and fear of losing control or going crazy.

 

People with depression typically report one or more of the following feelings including sadness, down or blue, irritable, hopeless, helpless or anxious.

Alternatively, and often in men, normal mood may be reported with a pervasive loss of interest in, or difficulty getting pleasure out of usual activities.

 

People suffering from depression report negative thoughts about themselves, others, the world and the future. Negative thoughts about the self may include: "I am weak", "I am a failure", "I'm not good enough", "I am useless"; negaive thoughts about people and the world may include "people are out for themselves", "the world is a bad place", "people think I'm weak", "my life is hopeless"; negative thoughts about the future may include "the future is hopeless", "I will never get better", "I will never be happy".

 

In order to cope with depressed feelings people with depression report withdrawal from their usual activities or social activities. They typically report engaging in less pleasurable and achievement related activities that usually assist in elevating their mood, inevitably leading to a negative downward spiral in mood.

 

Other behaviours seen in depression, often designed to regulate negative mood states, include emotional eating or alcohol/drug abuse.

 

Research suggests that those clinical depression are likely to have inherited a genetic predisposition to develop this problem. However, whilst approximately 50% of the tendency to become depressed can be attributed to inherited factors, approximately 50% is learned through our environment.

 

The development of depression may occur through mulitple and sometimes complex pathways where biological, psychological and social factors interact to influence mood and functioning.

 

The most common trigger for depression is stress. This may include chronic or repeated stress (for instance being in an ongoing abusive relationship, experiencing chronic pain or a significant illness) or a single acute stressor such as losing a job or relationship. 

 

Stress is a physiological process that occurs in the body where hormones are released into the bloodstream and these hormones interact with the nervous system causing the nervous system to slow down or the become "dysregulated". The nervous system may become slow to react to the environmentt or may become oversensitive resulting in excessive anxiety or agitation. In order to cope with these initial symptoms, people with depression often engage with unhealthy behaviours designed to manage negative feeling states such as withdrawing, resting and reducing activity, drinking alcohol or over eating. Inevitably these behaviours can lead to a worsening of depressive moods and feelings.

 

Depression, in a minority of cases, may be influenced simply by genetic or brain based factors where there are insufficient chemical messengers in the brain to maintain mood and adequate information processing. In these cases there is no identifyable stressor and depression is purely being caused by lack of efficient functioning of the brain.

 

Due to the multiple pathways that may lead to depression (biological, psychological, social), strengths in each or all of these areas may be protective. Biological protective factors may include: healthy and nutritious diet (chemical messengers in the brain are constructed from the nutrients in food), exercise (influences the production of serotonin and endorphins both important in the maintenance of good mood); psychological protective factors incude: effective thinking skills and the ability to evaluate situations, ourselves and the world in the most helpful ways; social protective factors include: healthy relationships and social support and good communication skills.

 

Deficits in any or all of the above areas, particularly in times of stress may influence the likelihood that problematic mood states may develop into depression.

 

A large body of research suggests that the treatment of choice for depression is Cognitive Behavioural Therapy. Medication such as Selective Serotonin Reuptake Inhibitors (SSRI) has also been shown to be effective in the treatment of depression. Research suggests that therapy and medication have relatively equal effectiveness in treating depression. However, a combination of medication and therapy has been shown to have additional benefits. Taking medication may improve mood and thinking processes enough to assist those suffering with depression to use the strategies learned in therapy more effectively. Research also suggests that those who attend therapy and take medication are less likely to relapse into depression when they cease taking medication.