Each and every person has suffered from depression at one time one or another in his or her life. However, the extent to which individuals suffer from depression varies from one person to another. Whereas some people undergoing depression may feel sad, others experience feelings of emptiness, apathy, and lifelessness.

Throughout history depression has been described in different versions. In the 19th century it was believed that depression is a condition arising from inheritance (Beck and Alford, 2009). Later on depression was associated with internal guilt and conflict. Depression was also linked to external conflicts. People have been suffering from depression since the inception of human life. Depressive disorders, as indicated by Knaus and Ellis (2006), can be referred to as a group of symptoms that mirrors a sad as well as irritable mood whose magnitude is high above normal sadness and grief. Sadness and irritability in depression are characterized by prolonged duration and greater intensity in addition to severe symptoms and functional incapacities as compared to normal grief. Signs and symptoms of depressions are not only characterized by negative feelings, mood, and thoughts, but also distinct changes in bodily functions (Knaus and Ellis, 2006).

Some of the specific changes in bodily functions associated with depression include: crying, reduced libido, decreased overall performance, and weight loss in addition to loss of appetite and sleep disturbance (National Institute of Mental Health, 2007). Most of these changes occur as a result of changes in the nervous system. Adverse consequences associated with depression include: increased health care costs and loss of productivity due to absenteeism from work. Depression is also believed to aggravate adverse conditions associated with various functional disabilities such as arthritis, diabetes and hypertension (MedicineNet, 2010). Depression is a major public health concern. It affects millions of people including approximately 10% of adults, 8% of teenagers and 2% of pre-teens (National Institute of Mental Health, 2007). The prevalence of depressive disorders in women is higher than in men. Hormonal and psychological factors in women are believed to be the major factors that result in the increased prevalence of depression among women. The effects of depression in men are also different from those in women.  Men are believed to have better coping mechanism to depressive disorders as compared to women (National Institute of Mental Health, 2007).

Beck and Alford (2009), state that the main cause of depression has not yet been discovered. However, depression is believed to occur as a result of combination of genetic, environmental, biochemical, and psychological factors. Various brain imaging technologies such as magnetic resonance imaging reveal that the brain structure of people who suffer from depression is different from that of those who do not (Knaus and Ellis, 2006). The parts of the brain which are responsible for mood, sleep, appetite, and behavior regulation function abnormally in people suffering from depression. Neurotransmitter imbalance in the brain is also believed to be a major factor that results in depression (Beck and Alford, 2009). Various types of depression tend to run in families. This suggests that these depressive disorders are genetically linked. Nevertheless, depression can affect a person who does not have a family history of the disorder. Genetic research reveals that depression occurs as a result of environmental influence on various genes (Knaus and Ellis, 2006). Trauma, especially the loss of a loved one, is also believed to result in depression.

Even though depression is a condition that can adversely affect the psychological health of a person, it is easy to detect and can be treated. Earlier detection and treatment are very effective strategies in the management of depression (Knaus and Ellis, 2006). Various diagnostic tests are carried out in order to rule out the presence of other diseases that may present in a manner similar to depression. Psychological evaluation is carried out, if the likelihood of a medical condition as a cause of depression is ruled out. Various medications used in the management of depression include: antidepressants, which function by bringing the concentration of neurotransmitters dopamine and norepinephrine among others, in the brain to normal levels.

Selective serotonin reuptake inhibitors (SSRIs) are the newest forms of antidepressants used in the treatment of depression (MedicineNet, 2010). Monoamine oxidase inhibitors (MAOIs) can also be used to treat depression (Beck and Alford, 2009). Ant-anxiety medications, stimulants and other medications may be used together with antidepressants if a patient is presenting with more than one psychological condition. Nevertheless, there is various side affects associated with the use of antidepressants. These include: headache, nausea, agitation, sexual problems, and insomnia. Other side effects associated with these drugs are: dry mouth, constipation, blurred vision, drowsiness and bladder problems. Psychotherapies can also be employed in the treatment of depression. Cognitive–behavioral therapy (CBT) and interpersonal therapy (IPT) are the main types of psychotherapies that are used in the management of depression (National Institute of Mental Health, 2007). Individuals are taught new ways of thinking in addition to behaving that are vital to alleviation of depression. Psychotherapies are effective forms of treatment of mild depression. Electroconvulsive therapy can also be employed as a treatment modality for depression (MedicineNet, 2010).

SparkNotes LLC, (2009), states that there are four main theories in abnormal behavior. These include: Biological Theory, Psychological Theories, Bio-Psycho-Social Integration, and The Diathesis-Stress Model. Biological theory of abnormal behavior states that defects in the functional as well as structural integrity of the nervous system result in abnormal behavior. Various types of biological abnormalities listed under this theory include: defective genes, structural brain abnormality, and neurotransmitter as well as hormonal imbalance. Psychological theory of abnormal psychological, on the other hand, has it that most of psychological life operate outside the realms of personal awareness.  Each and every person has fantasies, wishes and desires that arouse his/her anxiety. Individuals deal with these wishes through a mechanism referred to as defense mechanism (SparkNotes LLC, 2009). Peacock and Casey (2000), state that defense mechanism is a psychological process that an individual uses in order to get rid of negative feelings. Symptoms of abnormal psychology occur when the negative feelings are too strong for defense mechanism to handle.

Behavioral aspect of psychological theory of abnormal behavior takes into account the observable behavior of a person rather than the inner psychological life of a person (Peacock and Casey, 2000). This theory points out that abnormal behavior occur as a result of learning in addition to environmental experience. The cognitive aspect of psychological theory has it that incorrect perceptions arise from faulty assumptions and organization of beliefs (SparkNotes LLC, (2009). Bio-Psycho-Social Integration theory states that abnormal behavior occur as a result of the interaction of biological, psychological and social factors. The diathesis-stress model on the other hand states that individual differences, as far as abnormal behavior is concerned, occur as a result of interaction between psychological and biological factors. High stress in conjunction with low diathesis or low stress along with high diathesis can result in psychological disturbance (SparkNotes LLC, 2009). V Axes diagnosis is utilized throughout the psychological health system to offer an accurate and objective evaluation of assessment carried out by a clinician.  V Axes diagnosis is a scale that evaluates the overall level of psychological, social and occupational performance of an individual on a theoretical field (Peacock and Casey, 2000).

Reference:

Beck A., and Alford B., (edn 2), (2009), Depression: causes and treatments, ISBN 0812219643:

University of Pennsylvania Press

Knaus W., and Ellis A., (2006), The Cognitive Behavioral Workbook for Depression: A Step-by-

step Program, ISBN 1572244739: New Harbinger Publications

MedicineNet, (2010), Depression, retrieved on August 20, 2010 from http://www.medicinenet

.com/depression/article.htm

Peacock J., and Casey J., (2000), Depression, ISBN 0736804358: Capstone Press

SparkNotes LLC, (2009), Abnormal Psychology, retrieved on August 20, 2010 from

http://sparkcharts.sparknotes.com/psychology/abnormalpsychology/section2.php

The National Institute of Mental Health (NIMH), (2007), Depression, retrieved on August 20,

2010 from http://www.nimh.nih.gov/health/publications/depression/complete-index.shtml