8 Possible Causes of Depression

Depression is a mental illness that negatively affects the way you feel, the way you act, and the way you think. Millions of people all over the world fall victim to it every year, but most of us remain ignorant to its nature and causes. There are a lot of harmful myths and misconceptions surrounding depression, but making an effort to better understand it makes you more compassionate and better able to help those suffering from it. 

According to the American Psychological Association (2013), clinical depression as a mood disorder characterized by low energy, fatigue, loss of interest, lack of motivation, diminished ability to feel pleasure, and a depressed mood that’s present more often than not. The number one most rampant psychiatric condition worldwide, it’s estimated that over 1 in every 6 (16.6%) of people all over the world will experience depression at some point in their lives (American Psychiatric Association, 2015).

But while the symptoms of depression are clear and recognizable, studies have found a number of different reasons for why people develop depression. There are a lot of biological, psychological, and social factors that seem strongly implicated in its etiology, but it still remains to be seen as to whether they are a cause, effect, or contributing factor of depression. 

With that said, however, here are 8 of the most widely-researched causes of depression:

1. Stressful Life Events

Most people who develop depression report experiencing a stressful life event in the recent past, like being in an accident, losing a job, getting a divorce, having a child, or experiencing a death in the family (Carter & Garber, 2011). And while not everyone who goes through these things becomes depressed, that doesn’t mean that the people who do are “just overreacting”. Stress is relative and we all react to it in different ways and to varying degrees, so something like, say, the end of an important relationship might cause a person a lot more emotional distress than they know how to cope with, leading them to spiral into depression. 

2. Learned Helplessness

Next, another reason why people become depressed could be because they fall victim to learned helplessness. This particular “theory of depression” was pioneered by Martin Seligman (1975), the founder of Positive Psychology, who reasoned that people succumb to depression when they feel powerless against the negative events of their lives.

This happens when they have what psychologists call a “depressive attributional style”, which is internal (“This bad thing that happened is because of me”), stable (“This bad thing will keep happening to me”), and global (“Everything in my life is bad”). This kind of thinking is especially common in those who become depressed at an earlier age and it fosters a strong sense of hopelessness that negatively impacts them for the rest of their lives.

3. Negative Cognitive Styles

Another psychological explanation for depression is Aaron Beck’s (1976) theory of negative cognitive styles. Famous for developing Cognitive-Behavioral Therapy, Aaron Beck believed that depression was the result of a tendency to perceive events in a pessimistic way. Also known as “cognitive distortions”, he noticed problematic patterns of thinking in his patients such as catastrophizing (“This is a disaster! Everything is ruined!”), personalization (“This is all my fault!”), overgeneralization (“This sucks! I hate my life!”), selective abstraction (choosing only to see the negative in a situation), and magnification (fixating too much on a minor mistake). 

4. Hormonal Imbalance

Moving on to the biological factors that contribute to depression, hormonal imbalance is the most commonly cited one. Numerous studies have found that low levels of serotonin, in particular, are found in patients with depression. And because the primary function of serotonin is to regulate our emotions as well as other neurotransmitters (such as norepinephrine and dopamine), serotonin deficiency often results in mood irregularities, irritability, anxiety, poor appetite, and depressed mood (Thase, 2009). 

5. Overactive Endocrine System

A dysfunction in a person’s endocrine system is one of the most widely-accepted causes for anxiety and depression. Research shows that overactivity in the hypothalamic-pituitary-adrenocortical (HPA) axis results in an oversupply of cortisol and other stress hormones, which is common in those diagnosed with depression (Barlow, et al., 2013). This is most likely because stress hormones have an adverse effect on our neurons and leads to shrinkage of the hippocampus over time, causing impairment in sleep regulation, short-term memory, concentration, and other cognitive processes. 

6. Family History of Depression

A number of studies suggest that depression is a heritable disorder and that there is a specific gene or genetic pattern that makes a person more vulnerable to it than most. For example, having a relative with a mood disorder – be it depression or bipolar disorder – makes you nearly 3 times more likely to develop depression (Lan & Eley, 2010; Klein, et al., 2002). And having an identical twin with depression puts you at 80% more risk of developing the disorder yourself, more so than having a depressed fraternal twin (McGuffin, et al., 2003). These findings hold true even with relatives who don’t live with each other, so a strong genetic component is suspected to be the cause.

7. Dysfunctional Home Life

Growing up with an abusive family can leave a lot of psychological damage on a child, and sadly, most victims of early childhood abuse (whether it’s physical, emotional, or sexual) go on to develop depression, anxiety, PTSD, and other trauma-related disorders when they get older (Bradley, 2008). Coming from a broken family or being abandoned by a parent at a young age also puts a person at greater risk of depression, as well as having a parent or caregiver die when the child is still young (Teicher & Anderson, 2011). 

8. Lack of Social Support

Last but certainly not least, a lack of social support is an important contributing factor to a person’s depression. Having few or no close, meaningful relationships in your life makes it harder for you to be emotionally vulnerable with someone and cope with your emotions in a healthy, functional way. It leads you to feeling isolated and disconnected from those around you and fosters strong feelings of emptiness, loneliness, and worthlessness that could worsen into depression if left unresolved (Aneshensel & Stone, 1982).

Just as there might be a number of reasons why someone catches a cold or comes down with a fever, there are a lot of possible explanations as to why a person might struggle with depression. And the most likely answer seems to be that there is no single, universal cause, but rather, a combination of several different factors that may vary from person to person. 

So if you feel that you may be suffering from depression or know someone who is, don’t hesitate to reach out to a mental healthcare professional today and get the help you need.

References:

• American Psychological Association (2013). Diagnostic and Statistical Manual of Mental Disorders – 5th Edition. Washington, DC; APA Publishing.
• American Psychiatric Association (2015). “What is Depression?” Retrieved 07 April 2020 from https://www.psychiatry.org/patients-families/depression/what-is-depression
• Carter, J. S., & Garber, J. (2011). Predictors of the First Onset of A Major Depressive Episode: Stress and Negative Cognitions. Journal of Abnormal Psychology, 120(4), 779-796.
• Seligman, M. (1975). Learned helplessness: theory and evidence. Journal of experimental psychology: general, 105(1), 3.
• Beck, A. (1976). Cognitive Therapy and Emotional Disorders. New York, NY; International Universities Press. 
• Thase (2009).
• Barlow, D. H., Farchione, T. J., Fairholme, C. P., & Ehrenreich, J. (2013). Disorders of Emotion: A Unified Protocol for the Treatment of Depressive Disorders. New York, NY; Oxford University Press. 
• Bradley, R. G., Binder, E. B., Epstein, M. P., Tang, Y., & Ressler, K. J. (2008). Influence of Child Abuse on Adult Depression. Archives of General Psychiatry, 65(2), 190-200.
• Lan, R., & Eley, S. E. (2010). A Study on the Clinical Features of Major Depressive Disorder on Adolescents and Their Relatives. Journal of Abnormal Psychology, 111(38), 98-106. 
• McGuffin, P., Andrew, M., Sham, P., Katz, R., & Kardno, A. (2003). The Heritability of Bipolar Affective Disorder and the Genetic Relationship to Unipolar Depression. Archives of General Psychiatry, 60, 497-502. 
• Teicher, M. P., & Anderson, S. L. (2011). The Neurobiological Consequences of Early Stress and Childhood Maltreatment. Neuroscience & Biobehavioral Reviews, 27 (10); 33-44.
• Aneshensel, C. S., & Stone, J. D. (1982). Stress and depression: A test of the buffering model of social support. Archives of general psychiatry, 39(12), 1392-1396.