What Causes Depression?

A complex interaction between biological, psychological, and social factors is what causes depression.

  1. Biological Factors 
    1. Genetics 
    2. Biochemical Imbalances 
    3. Physical Conditions 
    4. Nutritional deficiencies 
  2. Psychological Factors 
    1. Core Beliefs 
    2. Psychological Disorders
    3. Personality Type
    4. Thinking habits 
  3. Social Factors 
    1. Past Trauma 
    2. Family Relationships 
    3. Peer Relationships
    4. Socio-economic Status 

You Did NOT Cause Your CHILD’s Depression 

I have worked with many young people and their families dealing with depression. If your child is depressed you might be wondering if it’s somehow your fault. The answer? It’s NOT. I have seen children from the most abusive homes imaginable not have depression afterwards.

On the other hand, I have also seen children with amazingly kind and loving parents die by suicide. The causes of depression are myriad, complex and interlinked. It’s essential that ALL the potential causes of depression are addressed to achieve positive outcomes. 

Biological Factors 


When I’m conducting a mental health assessment of a client I always ask about family history of mental illness. Why? Because genetics are a major contributor factor to whether or not someone will experience mental illness in their lifetime.

Researchers found that when twin’s who were adopted and raised in separate homes the likelihood of them both becoming depressed much higher than would be expected if genetics played no role. Your genetics can also affect your brain functioning which plays a big role in depression. 

Biochemical Imbalances

Brain scans of depressed people show that they typically have imbalances in their brain chemicals called neurotransmitters. Specifically- serotonin, norepinephrine, and possibly dopamine. The neurochemical serotonin plays a big role in happiness. This is why many drugs designed to treat depression are aimed at increasing the level of serotonin in the brain. This class of drugs is called selective serotonin uptake inhibitors (SSRI’s) and include Fluoxetine (Prozac), and Sertraline (Zoloft) among others. 

Watch this video to learn how serotonin levels are related to depression and ways of increasing serotonin production naturally. 

Physical Conditions 

It is estimated that one-third of people with a chronic illness or condition experience symptoms of depression. Physical illnesses contribute to chronic stress and strain on relationships which can lead to persistent low mood and depression. Research also shows that teens with autism (which is a neurological brain difference) are at a higher risk of depression, and the risk increases with their age and their level of cognitive functioning.

This is because adolescents who are better able to understand their limitations often feel the most depressed and discouraged about their ASD diagnosis. In addition, physical conditions can contribute to nutritional deficiencies which can contribute to depression. 

Nutritional Deficiencies

In his book The Breakthrough Depression Solution: A Personalized 9-Step Method for Beating the Physical Causes of Your Depression Integrative Psychiatrist Dr. James Greenblatt goes on a deep dive into how our nutrition affects our mental health. The modern diet and a sedentary lifestyle have contributed to deficiencies in key mineral and nutrients that are essential for health brain functioning and mental health.

Essential building blocks for mental health include Vitamin B12, Vitamin D, Essential Fatty Acids, and Zinc among others. In fact, when someone has treatment resistant depression (counselling and medication are ineffective) it’s highly likely there is a physical cause of depression that is being left unaddressed. 

Psychological Factors 

Core Beliefs 

Your core beliefs are a set of deeply held convictions that you hold about yourself the world and others. One way to determine what you core beliefs are fill in the blanks to the following questions “I am _____, other people are ______, the world is _____”. If you answered “I am unlovable, other people are jerks, and the world is going to shit”, then you probably have negative core beliefs. People with negative core beliefs are more likely to experience depression and other mental illnesses.

Our core beliefs are a byproduct of our worldview, life experiences, and how we interpret the world around us. Core beliefs are very stable but it is possible to change them. You can change your core beliefs by identifying them, and actively choosing to replace them with more helpful beliefs. Shifting core beliefs from unhelpful to helpful ones is one of the core processes underlying Cognitive Behavioural Therapy, an effective treatment for depression. 

Psychological Disorders

If you have another psychological disorder such as social anxiety this puts you at a higher risk for depression. For example, it is common for people with depression to also have other mental health disorders like anxiety, OCD or PTSD to name a few.

Anxiety can reinforce depression because it causes people to become afraid of doing things and interacting socially. This can lead to social isolation, and reduced physical activity which feeds into depressive symptoms of withdrawal and fatigue. It’s important that other mental health disorders are treated in order for depressive symptoms to improve. 

Personality Type

People high in neuroticism (psychological term for being emotionally sensitive) and introverts are more likely to experience negative thoughts. Many clients that I work with are very sensitive people which makes them kind and caring towards others. However when they feel slighted by others it causes deep wounds, and takes them longer to heal from it. Add to this introverted personality type (more likely to reduce social contact) and you have a recipe for depression. 

Decreased social contact, results in more time to reflect and ruminate on past grievances. In turn, rumination leads to negative attitudes towards others resulting in more isolation and so on. It’s important if you have these personality types to work on having a thicker skin (not caring what others think) and forcing yourself to engage socially so you don’t get caught in this vicious cycle. 

Thinking Habits 

Worry and rumination are two thinking habits that can contribute to anxiety depression. Worry is the process of thinking about all the potential negative events that could happen in the future. Rumination is the process of reviewing and reliving negative events from the past. Both are similar to being on a hamster wheel. That is to say, there is a lot of activity but not much progress.

The first step to stopping worry and rumination cycles is to become aware that you are doing it. The second step is to do something about it. The video below has some helpful strategies for dealing with rumination. 

Social Factors 

Past Trauma 

Adverse childhood experiences are correlated with the likelihood of future addiction and mental illness. Trauma can lead to post-traumatic stress disorder which interferes with sleep and is highly correlated to depression. Even if there is no formal diagnosis of PTSD negative experiences in childhood can negatively affect people’s core beliefs leading to depression.

That being said, not everyone who has had traumatic experiences will experience mental illness, and post-traumatic growth (positive development due to trauma) is also common. Trauma does not always need to be confronted directly to overcome it’s negative effects. However, there is evidence that writing you the events of your life into a coherent narrative has a positive impact on your well-being and sense of self-efficacy

Family Relationships 

Someone’s living situation has a big impact on their mental health. Children growing up with parents who are struggling with mental illness and addiction are at higher risk for those same problems. Adults living in the context of domestic conflict have higher levels of stress which are correlated with depression.

It’s crucial that any issue’s parents might be experiencing are addressed for the treatment of depression in children and youth. In addition, the strength of the relationship between parent and child is also one of the best predictors of positive outcomes for school performance and mental health in children. Check out my blog posts on relationships to for tips on how to connect with your kids.

Peer Relationships

Peer relationships can have a significant impact on the mental health of children and youth. In my work as a counsellor I have seen multiple times how bullying and harassment at school or a negative relationship with a teacher can result in school avoidance and social isolation which both contribute to depression.

For adults work environment has a big influence on mental wellness. In his book Lost Connections: Why You’re Depressed and How to Find Hope Johan Hari talks about how disconnection from meaningful work has become a large factor in increasing rates of depression worldwide. Meaningful work also contributes to educational opportunities and standard of living, key factors in well-being.

Socio-economic status 

Living in poverty causes increased stress and strain on families and children and is a risk factor for depression. Poverty is defined as a the lack of sufficient income to provide for the basic necessities of life consistent with the norms of society in which one lives.

Those living in poverty have reduce access to basic necessities like education, employment, and housing which are all essential for human growth and flourishing. It’s important that the basic needs of individuals are met before they can begin to heal from depression and other mental disorders. Once people’s basic needs are met, further increases in income do not result in increased happiness.

Can you think of anything else that might impact mental health and depression? Feel free to leave a comment or question below.

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