Depression 101

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Risk factors and causes of depression

Depression results from interactions between genetic, biological, environmental and psychological factors. Depression can begin at any age, but usually starts when a person is in their late teenage years, or in early adulthood (Wang et al., 2010). Many long-term mood and anxiety disorders in adults begin as high levels of anxiety in children (NIMH, 2018). Women, young people, those with persistent conditions and people with a family history of major depressive episodes are more likely to develop major depression (Wang et al., 2010).

Risk factors for depression include:

    personal or family history of depression
    major life changes, trauma, including intergenerational trauma, or stress
    certain physical illnesses and medications

Even though risk factors may increase someone’s chances of developing depression, it is not guaranteed that they will develop it.

Click each risk factor below to learn more.

Having a family history of major depressive episodes is the greatest risk factor for having a major depressive episode (Wang et al., 2010). It is not clear what accounts for this strong correlation, as it could involve a combination of genetics/biology, childhood trauma and current life circumstances (determinants of health).
Traumatic experiences can be any negative experience that deeply affects a person. They are unsettling and impact a person’s ability to adapt to the normal stresses of life. Traumatic experiences could include being in a car accident, witnessing violence, being abused or living through a natural disaster or a war. Trauma, especially in childhood, causes health disparities. It is a root cause of adult disease and high-risk behaviours. Trauma is more likely to affect the most vulnerable people and populations (Kimberg, 2016).

It is important to recognize that anyone could have past trauma (Kimberg, 2016). In fact, for clients in a clinical practice or service, the rates of trauma can be as high as 80 to 90 per cent (Saunders & Adams, 2014). A history of trauma is a major risk factor for depression.


First Nations, Inuit and Metis intergenerational trauma

The legacy of residential schools has deeply affected the mental health of First Nations, Metis and Inuit people. A research project that looked at the case files for a sample of residential school survivors found that 75 per cent contained information about mental health. The most common mental health diagnoses were post-traumatic stress disorder (PTSD), substance abuse disorder and major depression (Health Canada, 2017).

Depression can be both a cause and an effect of physical illness. People with depression are two times more likely to have a stroke and 1.5 times more likely to develop cancer. On the other hand, 17 to 27 per cent of people with heart disease and 22 to 29 per cent of people with cancer develop depression (MDSC, 2013).

Depression can emerge with physical illnesses, such as diabetes, cancer, heart disease and Parkinson’s disease, especially in adults who are middle-aged or older. Sometimes the medications for these illnesses can cause side-effects that may lead to depression (NIMH, 2018).

Depression 101 © , CAMH.

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