Environmental causes of depression are concerned with factors that are outside of ourselves. They are not directly related to brain function, inherited traits from parents, medical illnesses, or anything else that may take place within us. Instead, environmental events are those things that happen in the course of our everyday lives. These may include situations such as prolonged stress at home or work, coping with the loss of a loved one, or traumatic events. Sometimes researchers refer to these as sociological or psychosocial factors since they bring together events that happen out in society with the inner workings of a person’s mind.
It has long been understood that experiences we have in our lives can affect our state of mind. The relationships we have with others, how we are brought up, losses we have, and crises we encounter all may affect our thoughts, emotions, and behaviors. How we react to these environmental events may influence the development of clinical depression.
Stress and Depression
There appears to be a complex relationship among stressful situations, our mind and body’s reaction to stress, and the onset of clinical depression. It is clear that some people develop depression after a stressful event in their lives. Events such as the death of a loved one, the loss of a job, or the end of a relationship are often negative and traumatic and cause great stress for many people. Stress can also occur as the result of a more positive event such as getting married, moving to a new city, or starting a new job. It is not uncommon for either positive or negative events to become a crisis that precedes the development of clinical depression.Whether a stressful event itself can actually cause a person to become depressed is not fully known. There are times when we all must struggle with very painful situations in our lives. More times than not these changes do not result in a person becoming clinically depressed. In fact, sometimes people become depressed even when there is little or no stress in their lives and everything seems to be going very well. And, no single stressful event will cause depression to develop in every person. The same type of stressor may lead to depression in one person, but not another.
If a stressful experience causes a person to become depressed, it may happen indirectly. In other words, if a young woman with a family history of major depression suffers the death of a loved one, she may become clinically depressed. In this situation it is not necessarily the traumatic loss itself that caused the development of depression, but the combination of a genetic predisposition with the stressful event that made her vulnerable to becoming depressed.
For those who struggle with more chronic depression, the effects of stress may be more complicated. A stressful event such as a job loss or the death of a loved one is more likely to come before a first or second depressive episode. After that, further depressive episodes may develop spontaneously. It is not certain why stress may lead to depression in this way. However, researchers have theorized an explanation called the “kindling effect,” or “kindling-sensitization hypothesis.” This theory surmises that initial depressive episodes spark changes in the brain’s chemistry and limbic system that make it more prone to developing future episodes of depression. This may be compared to the use of kindling wood to spark the flames of a campfire. Since early episodes of depression make a person more sensitive to developing depression, even small stressors can lead to later depressive episodes.
Some people may become depressed as a result of having to struggle with chronic stress. These constant difficulties may come in the form of having to juggle multiple roles at home and work, making major changes in lifestyle, being in an abusive environment, etc. They may also come with important and normal transitions in life such as late adolescence and early adulthood when many people separate from their families to establish their own independence. Middle age may require adjustment to changes in fertility and virility, children leaving the home, concern about job advancement, and a re-evaluation of accomplishments in life. Retirement is another time of major change as some people struggle with a reduction of position and finances. If a person is under continuous stress, a single difficult event may be more likely to induce a depressive episode. For instance, if a middle-aged woman is in an unhappy marriage, she may be more likely to become depressed after her youngest child leaves home for college. The event of her child leaving home may not by itself have been enough to lead to depression, but the constant stress of an unhappy marriage combined with this event may be enough to trigger clinical depression.
In studying how stressful events may lead to depression, researchers have developed a theory called, “learned helplessness.” This theory states that when people experience chronic or repeated stressful events, they learn to feel helpless. This feeling of helplessness is strengthened when a person believes he or she has no control over the stressful situation. Although the research to support this theory was initially done with animals, the effects of learned helplessness may be seen in depressed humans. People who are depressed very often have negative beliefs about their ability to manage aspects of their lives based on perceived failures in the past. For example, imagine an adolescent girl living in a home with verbally abusive parents who tell her that she is stupid and cannot do anything right. Over time the young girl may believe her parents and come to doubt her abilities and self-worth. She may begin to feel helpless and believe that most things are beyond her control. This feeling of helplessness may make her vulnerable to developing clinical depression at some point in her life.
Many times, people who become depressed report that a single traumatic event happened just prior to their becoming depressed. Painful experiences such as the death of a loved one, divorce, a medical illness, or losing everything in a natural disaster may be so impactful as to trigger clinical depression. Events like these take away a sense of control and cause great emotional upheaval. Some traumatic events may cause more distress for one person than for another. For instance, a man who loses his wife to death may be more prone to becoming clinically depressed than a woman who loses her husband. This may be because the loss of a wife can lead to additional losses for a man. He might lose contact with children and other family members. He may also become more emotionally distressed and isolated if he has difficulty reaching out to others. Women who lose their husbands may be more willing to seek out emotional support.
A person’s recovery from depression may also be affected by traumatic events. The more stress and difficulty a person experiences, the longer a recovery from depression may take. For example, imagine a depressed woman in an unhappy marriage who finally decides to file for divorce. If the process becomes prolonged with disputes over finances or custody of the children then her recovery from depression could be slowed down greatly. On the other hand, if the same woman perceived the divorce as something positive in her life, perhaps she was leaving an abusive relationship, then she might have a more speedy recovery.
People who become clinically depressed have generally experienced more severe difficulties in childhood than those who do not become depressed. These difficulties may include sexual or physical abuse, a turbulent upbringing, separation from a parent, or mental illness in a parent. Some researchers believe that a problematic childhood may trigger an early-onset of depression (first episode occurs before age 20). The most significant event that seems to be related to clinical depression is separation from or death of a parent before the age of 11.
It is not clear just how a difficult childhood can result in adult depression, but there are a few theories. One theory suggests that children who experience great unhappiness growing up have a harder time adjusting to changes in their life such as adolescence and the new roles of adulthood. Another theory is that these children may either lack appropriate emotional development or they become emotionally damaged making them vulnerable to developing depression. Experiencing great difficulties as children, these individuals may be more likely to have low self-esteem, feel powerless, and become dependent on others to make them feel good about themselves. These kinds of traits may increase a person’s susceptibility to depression. Still another theory has to do with the developing brain of a young child. Early experiences may affect the development of the limbic system in the brain. If a child experiences great emotional distress, this could affect his or her ability to adapt to new environments and regulate emotions.
During World War II there were a number of children who were separated from their mothers. It was noticed that these children became depressed after going through several stages of grief. First, the children cried strenuously for their mothers. Then the children became very agitated. Afterwards, they became despondent and still. Lastly, they became very withdrawn. This severe reaction to losing their mothers is known as anaclitic depression. This same type of reaction to separation has been observed in studies with monkeys. In these studies, the monkeys secreted higher amounts of cortisol (a stress hormone) during the earlier stages of grief. It was found that the more cortisol that was released into the blood, the more intense the monkey’s depression became later on. In approximately one-half of all depressed humans there are high levels of cortisol in the blood.