What causes depression?
The symptoms of depression are relatively universal: loss of interest in daily activities, difficulty sleeping or increased sleep, a sad or irritable mood, reduced or increased appetite, fatigue, difficulty concentrating, problems making decisions, feelings of worthlessness and guilt, and thoughts of suicide or death. Many people also experience physical symptoms such as body aches or increased sensitivity to pain. While the symptoms of depression are easily identifiable, the causes of depression can vary greatly.
Depressive symptoms can be caused by a medical condition, such as a thyroid disorder, or by external chemicals including medications, illegal drugs and alcohol. Sometimes hormonal changes, including those that occur during the week prior to menstruation or after the birth of a child, can create symptoms of depression. Other times, depressive symptoms can be caused by environmental factors such as reduced exposure to light or inability to access important physical, social, or reproductive resources.
Finally, there are depressive symptoms typically viewed as being caused by a mental health disorder. However, as you will read below, what we call now call depression is influenced by many factors and is not necessarily the result of a genetic disorder. While some symptoms of depression may be caused by genetic factors, other types depression are created by thinking patterns, lifestyle patterns and social factors.
What we can change and what we cannot:
There is a great deal you can change about your mood and a great deal you cannot. You cannot change the genetics that underlie your biological tendencies towards positive or negative moods. You can, however, choose to modify the chemicals present in your brain by getting regular exercise, taking medication, changing your diet, and by avoiding harmful substances such as illegal drugs or alcohol. Although your biology is relatively static, you can also change the way you choose to view the world, the meaning you give to negative feelings, how you spend your time, and the way you choose to interact in your social environment. All of these factors contribute to your emotional state and research suggests that it is possible not only to reduce feelings of depression, but actually increase the amount of positive emotion that you experience.
Depression is not a useless emotion:
Before trying to get rid of negative emotion it is important to consider that depression can actually be good for you. This sounds like strange idea, but there are some very important reasons to believe that it is true. While depression is typically viewed as a mental disorder, in reality, it is not a useless emotion. Evidence suggests that depression functions to stop us from pursuing goals that are unattainable and to conserve energy in times when resources are scarce. For example, it is helpful to lose your appetite and not expend energy in situations when there is no available food. Unfortunately, the environment we live in has changed significantly over the course of human existence and sometimes depression no longer serves the purpose of helping us survive.
Biological aspects of depression:
A great deal of research has been done to understand the biological aspects of mood. Some of the best studies involve identical twins adopted and raised in separate families. Researchers have found that about fifty percent of your temperament, such as how much positive and negative emotion you feel, can be accounted for by genetic factors. Unfortunately, while we know that genetic factors are involved in depression, the specific biological mechanisms of depression remain poorly understood.
One genetic factor that has been found to be related to depression involves the serotonin transporter gene, of which there are both long and short forms. Individuals who inherit the short form of the gene from both parents appear to have an increased risk of developing depression. Modern psychiatric medications function by changing the proportions of chemicals, such as serotonin, in you brain. In addition, exercise causes you to release large amounts of chemicals called endorphins and has shown to be effective in relieving symptoms of depression.
Psychological aspects of depression:
The way that you think about problems can have a significant impact on whether or you become depressed. There are wide variety of thought patterns that can lead to depression. Listed below are some of the more common causes and a potentially healthy alternative:
- Pessimistic Depression: Pessimism is characterized by a belief that your current problems are due to character flaws in yourself or others, are going to last a long time, and are going to be pervasive over many areas of your life. People who are pessimistic become depressed when they reach a point of hopelessness where all action seems pointless. While in some situations this is important for survival, we now live in a complex world where persistence is essential to success. People prone to depression can experience a painful cycle in which they fail because they become depressed and where each failure confirms the belief there is something wrong with them.
- Pessimistic Realism: Traditionally people who suffer from depression were thought to have skewed views of their surroundings. However, evidence shows that pessimists are often more accurate in their assumptions regarding the amount of control they have over a situation and how others view them. The problem with pessimism is not so much in its accuracy but in its utility. Depression is harmful when it causes you to give up in situations where more effort is needed to be successful.
- Optimistic Depression: Depression can also result from a type of heedless optimism in which you cling too tightly to situations that you really need to change. Common examples of this include remaining in chronically stressful jobs and unproductive romantic relationships. Choosing to remain in these situations can expose you to repetitive failure and cause feelings of depression to escalate until your body literally forces you to change the situation.
- Enlightened Optimism: The ideal outlook is a kind of enlightened optimism where you are able to remain hopeful and persistent when continued effort is necessary while also being able to recognize when continued effort towards a goal is ultimately unhealthy and perhaps dangerous.
Why bother to be more optimistic?
Happiness, optimism, and positive mood have been associated with longer life span, better health habits, lower blood pressure, stronger immune systems, increased capacity to cope with pain, higher pay, better job evaluations, increased productivity, better problem-solving skills, increased marital satisfaction, greater likelihood of being in a relationship, a more active social life, and higher levels of altruism. These are compelling reasons to consider making an effort to become more optimistic.
Unlike your biological temperament, optimism and pessimism are beliefs under your conscious control. The fact that evidence suggests we can change these beliefs is one good reason to be hopeful that you can actually learn to be happier. While it will always be important to recognize when you are wasting energy on an unproductive goal, in the long run, if you are prone to depression you are likely to benefit from a conscious effort to fight pessimistic tendencies.
Behavioral aspects of depression:
Research has found that people who spend a great deal of time focusing on their problems actually suffer increased rates of depression. Not focusing on your problems when you are depressed can seem counter intuitive. Most of us naturally try and solve problems as a way to make ourselves happier. However, because depression causes fatigue, difficulty concentrating, and feelings of hopelessness sometimes it is very important to be able to distract yourself. The best way to do this is with activities, such as exercise, that can directly improve your mood, or activities such as playing music that create focused attention. The important thing is to pick forms of distraction that are good for you as opposed to activities like substance use or overeating that can have significant negative repercussions.
Social aspects of depression:
One possible reason that depression has become so common in our society may lie in the vast social and cultural changes that have taken place over the last forty-thousand years. Many differences exist between traditional societies and the world we live in now. Some of these differences may contribute significantly to the development of depression. People from traditional cultures spend much of their time outside, under the sun, engaged in strenuous physical activity while surrounded by family members and individuals they know well. Contrast this to the day of the average office worker which is isolated, spent under florescent lights, with almost no physical activity.
Our modern-day economic and social structure may play another role in depression. Pressure to move where jobs are available often results in the physical separation of families. Compounding this is a cultural expectation that adult children live separately from their families even before they are married. In addition, individuals are getting married later and are more likely to get divorced than in the past. Isolation has been found to be related both to depression and suicide. Although their is no conclusive evidence that the increasing frequency of depression is caused by social factors, it is notable that depression is less frequent in individuals who have large social networks, strong religious beliefs, and who get more exercise.
References
Keedwell, Paul. How Sadness Survived. Radcliff Publishing, Oxford, New York, 2008.
Seligman, Martin. Authentic Happiness. Free Press, New York, New York, 2002.