What Causes Depression?

If you are concerned about the mood of a friend or family member, you may be wondering what causes depression. There is no single factor that causes depression, and each person may have slightly different influencing factors. Generally, a combination of biological, psychological and environmental factors lead to depression. The following paragraphs will outline more about the factors that cause depression.

1. Depression and brain disorders. The leading causes of depression are linked to disorders of the brain. The National Institute for Mental Health reports that extensive research using MRI imaging has shown that sufferers of depression have different looking brains than those without depression. In particular, the areas corresponding to mood, thinking, sleeping, appetite and behavior appear irregular.
2. Neurotransmitter imbalances. Neurotransmitters in the brain can also be a factor that causes depression. Neurotransmitters act as chemical messengers between different parts of the brain and the nervous system. According to an article by El Paso Mental Health and Mental Retardation, three neurotransmitters are linked to depression. Low levels of serotonin, norepinephrine and dopamine can lead to depressive states. Serotonin is involved in many important functions including mood, sleep, eating, aggression and sexual behavior. Norepinephrine may be involved in a couple of ways in causing depression. Older research suggested that low levels of norepinephrine could lead to depressed moods. Other research has shown that norepinephrine helps us respond to and deal with stress. People with inadequate norepinephrine supplies may be more susceptible to stress-related depression. Dopamine is involved in our desire to seek out rewards and our ability to feel a sense of well-being or pleasure. Insufficient levels of dopamine could be one of the causes of depression.
3. Environmental stress. Environmental factors and stress are also linked to causing depression. A study published in the Journal of the American Medical Association conducted an overview of fourteen existing depression studies and found that patients with stressful life events had a 41% higher chance of developing depression.
4. Trauma and depression. Similarly, trauma is an environmental factor that causes depression. The National Center for Post-Traumatic Stress Disorder reports that those returning from war zones often have feelings of guilt, regret and painful memories that make it hard to readjust to life at home. Trouble dealing with PTSD issues and adjusting to life at home can be a traumatic event that causes depression.