Depression may be a consequence of genetic, developmental and/or psychosocial factors.
Depression usually follows a trigger in a genetically predisposed individual. Thus, it is usually due to a combination of factors rather than a single cause. Causes of depression include:
- Genetic Effect: Certain genes predispose a patient to developing depression. These are usually inherited from the parents. Variations in the serotonin-transporter gene or in the DNA sequence named G1463A have been associated with depression. Patients with inherited forms of depression usually have parents suffering from the same condition. However, it is not necessary that all patients who have a family history of depression will suffer from the same.
- Gender: Women are more likely to suffer from severe depression. They are also more likely to admit that they are suffering from depression and seek treatment.
- Personality Traits: Certain personality traits predispose to depression. These include low self-esteem, excessive anxiety, negative thinking and a feeling of being over dependant or a feeling of superiority over others.
The above factors cannot be eliminated, but understanding that these conditions could be behind depression may help in dealing better with the condition.
- Stress: Any condition that causes stress at work or home could trigger depression. These include bereavement or a job stress. Marital factors like unhappiness in marriage, divorce or separation could also lead to stress. A child could get stressed out at school, leading to depression. Thus, the cause of stress should be identified and if possible eliminated or the patient should be taught to deal with the stress.
- Chronic Illnesses: Chronic illnesses, especially those associated with pain, inability to function normally or express one self, result in depression. These include conditions like rheumatoid arthritis and stroke, which restrict movement and potential life-threatening conditions like severe heart disease and cancer. A problem with learning results in depression in children and adolescents. Some hormonal problems like hypothyroidism and perimenopause are associated with depression. With hormonal replacement, these conditions can be controlled without the need for antidepressant medications.
- Postpartum Depression: The hormonal as well as physical changes following delivery predispose the mother to depression. It occurs between 2 weeks to 6 months following delivery. New mothers should be provided adequate support to deal with depression in the postpartum period.
- Loneliness: A lonely life increases the chances of suffering from depression. Such people should be encouraged to spend more time in company of family and friends.
- Alcohol: Alcohol may stimulate the person for some time, but later brings about depression. Some depressed people try to drown their sorrows in alcohol, which leads to further worsening of the condition. Adequate counseling to give up alcohol could help these individuals deal with their depression.
- Drugs: Drugs that can cause depression include prednisone, some antibiotics, antihypertensive medications like methyldopa, clonidine and beta blockers, antiparkinsonism medications like levodopa, interferon treatment and birth control pills. With some drugs like lamotrigine, topiramate, and gabapentin, the depression may be severe enough to drive the patient to suicide. A list of medications should be obtained from a patient with depression. Substance abuse with drugs like cocaine is also associated with depression.
- Diet: A diet deficient in vitamins like folic acid and vitamin B12, which are necessary for brain function, can cause depression. A replacement of these minerals could help to deal with this type of depression.