Individuals affected with depression usually experience several bouts of depressive episodes. The symptoms almost occur every day and gradually begin interfering with the daily activities of the individual. The following are the signs and symptoms exhibited [6]:

• Too little sleep or excessive sleeping
• Loss of appetite accompanied by weight loss in some, while increase in appetite and weight gain in others
• Low level of mood characterized by loss of interest in normal activities
• Lack of energy, fatigue and difficulty in carrying out simple tasks
• Angry outbursts and feeling of irritation and frustration
• Poor concentration and inability to make decisions
• Feeling of worthlessness that causes suicidal thoughts and suicidal attempts
• Unexplained physical ailments such as back ache and headache

A combination of tests would help in diagnosis of depression. The following methods would be employed for diagnosing the condition:

• Physical examination: At the preliminary level, a thorough physical examination is carried out to check for presence of physical ailments if any; because many a time depression is linked to physical ailment. In addition, the psychologist would also ask various detailed questions concerning health of the individual [7] [8].
• Laboratory tests: Blood tests to detect complete blood count are required to assess the presence of underlying disease conditions such as thyroid disorders.
• Psychological examination: In this, the individual is asked in depth questions about the symptoms, thoughts and feelings. He/she are also asked to fill in a questionnaire to arrive at a definite conclusion.
• Imaging studies: CT scan and MRI scan of the brain can be considered to evaluate underlying disease conditions which are causing depression.

A combination of treatment regime has been proved to be effective for individuals with depression. The following methods are employed in treating depression:

• Medications: Antidepressants such as serotonin-specific reuptake inhibitors (SSRIs), serotonin–norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants and atypical antidepressants are used for treating depressions. Amongst these classes of drugs, antidepressants containing SSRIs are considered to be safe with fewer side effects. In addition to antidepressants, individuals may also be put on antipsychotics and mood stabilizers to enhance the effect of medications.
• Psychotherapy: This method involves interpersonal therapy, cognitive behavioral therapy and commitment therapy that helps individuals to overcome the condition through counseling [9]. 
• Electroconvulsive therapy is a process wherein electrical currents are imparted to the brain which significantly improves the levels of neurotransmitters providing immediate relief from severe depression. It is a method of choice for those individuals for whom medication and other therapies did not work.
• Transcranial magnetic stimulation is a process in which magnetic impulses are passed on to the brain which stimulates the nerves cells involved in mood regulation [10].

A high incidence of morbidity and mortality is associated with depression owing to increase in suicidal attempts amongst the depressed population. The prognosis of the condition is good with treatment as about 70 to 80% of individuals report significant reduction in symptoms of depression when given appropriate treatment. However, it has also been observed that about 50% of individuals do not respond to the initial phases of depression [5].

The exact cause of depression is not clearly understood. However interplay of various factors has been known to play a role. The following factors can cause depression:

• Brain chemical imbalance: Neurotransmitters are brain chemicals that are known to play a vital role in causation of depression. Imbalance in the level of neurotransmitters can trigger depressive symptoms.
• Physical changes: Individuals with depression are thought to have certain physical changes in the brain which again are a significant factor that can help determine the causative factor.
• Genetic factors: Certain genes are known to play foul in causation of depression as this mood disorder is thought to run in families. Individuals with family history of depression are more prone to suffer from this disorder.
• Hormones: Hormonal changes or imbalance due to certain disease conditions can cause depression.
• Life events: Individuals who have suffered the loss of loved ones, or have undergone physical or mental trauma during childhood are likely to develop depression in the future.
• Drug abuse: Use of certain medications or recreational drugs can also trigger symptoms of depression [2].

Depression is a common mood disorder affecting more than 20 million individuals in the US. The lifetime incidence of depression amongst men and women in the US has been estimated to be 12% and 20% respectively. Depression is a more common phenomenon amongst the women population [3].

It has also been reported that the incidence of depression is higher amongst the elderly population owing to advancing age and increase in prevalence of medical illness and institutionalization in this age group.

The pathophysiology of depression is not clearly understood. Certain clinical trials have pointed towards disturbance in the various neurotransmitters to be a major factor. In addition, development of vascular lesions that damages the functioning of the neural networks involved with emotional regulation play a significant role in development of depression. When the brain activity of affected individuals were studied through neuroimaging tests, it was revealed that depressed mind is associated with decreased metabolic activity in neocortical structures with an increase in metabolic activity of limbic structures [4].

Depression can seldom be prevented. However, certain steps can help avoid its onset. These include:

• Taking help of family and friends when feeling low or sad
• Considering medical intervention when first signs of depression appear
• Working out various ways to keep stress at bay

Such a type of mood disorder if not treated on time can make life worse for the individual living with it. Depression requires long term treatment and individuals generally do better with medications and psychological counseling. Affected individuals exhibit symptoms of constant feeling of sadness and lack of interest in activities [1]. Depression is also termed as major depressive disorder or clinical depression.

Definition

Depression is a type of mood disorder characterized by constant feeling of sadness accompanied by lack of interest in life. Such a type of condition can strike individuals at any age and is more prevalent amongst the female population.

Cause

Depression is thought to occur due to interplay of various factors such as genetics, unpleasant life events, hormonal imbalance and drug abuse. Individuals with certain underlying disease condition can also fall prey to depression.

Symptoms

Individuals with depression exhibit signs of sadness, lack of interest in various activities, loss of appetite or sudden increase in food cravings, lack of sleep, poor concentration, lack of energy and fatigue.

Diagnosis

Individuals who seek medical advice are asked to fill up a questionnaire containing list of questions to better understand their condition and thought process. In addition, blood tests and imaging studies will also be required to diagnose underlying disease conditions.

Treatment

Depression is best treated through combination of medication and psychotherapy. Those who fail to respond to these modes of treatment are given electroconvulsive therapy.

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