Depression can occur only once in life but people can show multiple episodes of depression over the cause of their lives [7]. During these episodes, the following symptoms can be seen either daily or intermittently:

• Feelings of sadness, unhappiness or emptiness
• Angry outbursts or frustration over small matters
• Loss of interest in normal activities like sex
• Sleep disturbances such as insomnia or excessive sleeping
• Tiredness and lack of energy
• Changes in appetite (usually weight loss as a result of reduced appetite but increased cravings for food and weight gain is seen in some people)
• Anxiety, agitation or restlessness may be seen
• Slowed thinking, speaking or body movements
• Fixations on past failure
• Difficulty in making decisions or concentrating on tasks
• Constant thoughts of death (suicide)
• Unexplained bouts of physical problems such as back pain or headaches

Diagnosis for MDD may involve one or more of the following [8]:

• Physical examination: This will involve questions concerning the medical history of the patient.
• Laboratory tests: This may include blood and thyroid tests.
• Psychological evaluation: This is the chief diagnostic procedure for this condition as it focuses on finding out the symptoms, thoughts and behavioural patterns of the individual. 

However, results obtained from the use of depression screening or rating scales are not enough for diagnosing depression. They may also be imperfect when dealing with elderly patients.

MDD is known for its major significant potential morbidity and mortality [6]. This is because it contributes to suicide, incidence and adverse outcomes on medical illnesses, lost work time, substance abuse as well as disruption in interpersonal relationships.

With appropriate treatment, 70-80% of individuals who have major depressive disorder can see a significant reduction in symptoms. 50% of patients will not respond to the initial treatment trial. 20% of people with untreated MDD in its first year will continue to meet the criteria for the diagnosis while an additional 40% can have a partial remission.

The specific etiologic factor for major depressive disorder remains unknown. As is the case with most psychiatric disorders, major depressive disorder often appear to be a multifactorial and heterogeneous group of disorders which may involve a variety of factors such as [3]:

• Biological factors: In people with MDD, physical changes in their brain have been noted. The significance of the changes remains uncertain but it is believed that it can be used to pinpoint causes. 
• Neurotransmitter imbalance: This has been implicated as a major etiologic factor in dealing with depressive symptoms.
• Hormonal changes: This may be as a result of thyroid problems, menopause as a well as a number of other conditions. 
• Inherited traits: The genes responsible for MDD have not yet been identified but a genetic predilection has been suspected. 
• Traumatic events: Some life events have been known to trigger MDD in some people. This may include loss of a loved one, financial difficulties, excessive stress etc.

There are no specific methods of preventing depression but these strategies have been proven to be helpful [10]:

• Take active steps to control stress and undergo sessions geared towards boosting self-esteem.
• Reach out to people when in crisis to help you go through rough patches.
• As soon as you notice signs of depression, get treatment as quickly as possible. 
• To help prevent recurrence, long term maintenance treatment is advised. 

Major depressive disorder (MDD) is a mental disorder that is characterized by a pervasive and persistent low mood often accompanied by a loss of interest in everyday activities and low self-esteem [1]. The condition is also known as clinical depression, major depression, unipolar depression, unipolar disorder and recurrent depression (when episodes are repeated).

Depression as a term can be used in a variety of ways. It is usually used to depict the MDD but it may also refer to other mood disorders or low mood [2]. Major depressive disorder is a disabling condition that often affects the family of an individual, their work, school life, sleeping and eating habits as well as general health. This condition is highly linked with incidences of suicide.

Major depressive disorder refers to the disorder that causes a persistent feeling of sadness and loss of interest. It is also known as a major depression, major depressive disorder or clinical depression. It affects the way you feel, think and behave and it can also lead to varying degrees of emotional and physical problems.

Patients of major depressive disorder can have difficulties in doing their normal daily activities and can make some people see life as not worth living.

This condition can affect anyone ranging from adolescents to adults and affects both sexes equally.

Contrary to what some people feel, depression isn’t a weakness and is not something that will pass over time. It can require long term treatment in some cases. The chances of recovery from depression are very good as long as the individual is given medical and psychological counselling.

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