Stress, Trauma, and Depression
Many people with major depressive disorder report that a stressful event (such as the list below) caused their first or second depressive episode. Research suggests that later depressive episodes (starting with the third) tend to develop in the absence of any particular stressor. Some scientists call this phenomenon the "kindling effect", or "kindling-sensitization hypothesis." According to this idea, initial depressive episodes create changes in the brain's chemistry that make it more likely that future episodes of depression will develop (or kindle, if you think about a spark starting a fire). Since early episodes of depression make a person more sensitive to developing later episodes, even a small series of daily hassles can trigger ongoing depressive episodes.
Stressful experiences often take away a person's sense of control. They can promote a sense of helplessness or hopelessness. This can cause great emotional stress and pain. The effects of stressful events are typically experienced quite differently by different people. Stressful events that don't bother one person may cause intense distress for another. Also, stressful events do not have to be negative to cause problems. Even positive life changes such as getting married or having a baby can trigger a depressive episode.
A variety of social or relational interactions or events can trigger depression. Some common examples include:
- Death of a loved one
- Divorce or marital problems such as an affair
- Loss of a job, financial problems, or poverty leading to homelessness
- A chaotic, unsafe, and dangerous home life such as violence in the family
- Abusive relationships that undermine self-confidence
- Social failures such as friendships that fall apart
- Moving to another city
- Experiences that cause learned helplessness in which one believes that they have no control in life
- Serious trauma such as abuse, neglect, rape, etc.
- Social isolation
Exposure to trauma may provoke a particularly intense form of stress reaction. Traumatic events include being a victim of or witness to violence, the death of another, or your own near death experience. Examples include rape, murder, torture, abuse, accidents, terrorism, and combat experience. Many people who develop depression previously experienced traumatic situations during their childhood years. This may have been sexual, emotional, and/or physical abuse or separation from a parent (through death or divorce).
Some people, including children, develop a psychological reaction to a traumatic event known as PTSD (post-traumatic stress disorder). Individuals with this condition repeatedly relive their trauma in the form of nightmares and disturbing daytime memories. They may also experience sleep problems, feeling numb, or become easily startled. They may lose interest in things they used to enjoy and have trouble feeling affectionate. They may feel irritable, more aggressive than before, or even violent. PTSD and major depressive disorder occur frequently following traumatic exposure. They can happen as separate disorders or both conditions can be present at the same time. For more information about PTSD, please visit that topic center.
As we discussed earlier in our section on psychoneuroimmunology, the relationship between stress and depression is not surprising. Many people who are depressed show high levels of cortisol (a stress hormone) in their blood. This has led some researchers to speculate that depression may be a variety of stress response itself.
If social events can cause depression, they can also help prevent it from occurring in the first place. One of the most well-studied sociological factors that helps prevent (or buffer against) depression is known as "social support." Social support simply refers to whether or not people have access to and make use of a network of interpersonal relationships for supportive purposes. People receive social support from their family, friends, work and school colleagues, and other acquaintances. Social support networks provide a shoulder, guidance, love, caring, entertainment, laughs, and other types of mental and physical assistance during times of need and crisis. For example, people who have someone with whom to discuss daily frustrations and troubleshoot life challenges are generally less stressed than individuals who are isolated. A social support network can be a tremendous help when you are sick or overwhelmed. They can run errands for you, provide emergency child care, etc. Social support networks can be important in helping people change unhealthy lifestyle habits, such as excessive drinking, or in adopting new habits. For instance, it is easier to maintain an exercise program when you exercise with a friend. Members of your support network also serve as a monitoring and feedback system. They may notice that your depressive symptoms are worsening and urge you to visit your doctor. They may help to point out symptom improvements that may come about as a result of treatment that you yourself may not notice.
Belonging to a social support network can also increase your sense of purpose and self-worth. Interestingly, research suggests that the size of your social network itself is not important. What matters is how well and how closely connected you are to the other members of that network. People who have lots of casual acquaintances and few close confidants are actually worse off than people who share close and meaningful connections with only a small number of friends.