What causes Depression?

Published on July 3, 2013


Why it is important to understand the causes of clinical depression?

Understanding what causes depression enables one to design the optimal treatment plan. For example, if you moved from the tropics to Canada and did not see the sun for days at a time then, your psychotherapist might point out that there is scientific evidence that lack of sunlight is correlated with depression and suggest that light therapy might be the treatment of choice. Another reason for knowing the cause of our depression is that many of us are curious to know what happened to us. Furthermore if we don’t know why we are depressed, our depression can talk us into believing that we brought it upon ourselves because we are bad or stupid people or that we should feel guilty even for being depressed. Understanding the cause of depression can stop us from this kind of self blaming.

The causes of clinical depression are usually extremely complex. Recent research has shown that the cause of clinical depression can be surprisingly complex:

  • Genes. In a relatively small number of cases genes may directly cause depression. I will discuss in a future post a recent study which has contributed greatly to understanding of how genetic factors operate in the etiology of depression.
  • Environment. A vast array of environmental factors can contribute to the onset of clinical depression. The most obvious of these are life stressors of which of course there are a great number (See the list below).
  • Interaction between genes and environmental factors where genes exert a causal effect on whether the environmental factor will influence risk. Recent research indicates that genes may increase the sensitivity to life stressors such that we are more disposed to respond to a life stressor by becoming depressed than we would if we did not have that gene.
  • Interaction between environmental factors and genes where environmental factors exert a causal effect on genes. This is a newly considered type of interaction called epigenetics which adds a new layer of complexity. I expect epigenetics will increase understanding of how developmental trauma in childhood can result in adult complex PTSD (also called condependency) and one of its main symptoms which is depression.

Some specific life stressors which can be important in causation of clinical depression. The life stressors which have been shown by research to increase the risk of developing clinical depression include, but are not limited to those listed below:

  • Interpersonal difficulties
  • Loss of important social and interpersonal relationships.
  • Developmental trauma (codependency.
  • Social exclusion, stigmatization, or discrimination.
  • Loss of social status.
  • Sexual and/or reproductive difficulties
  • Failure to attain life goals
  • Having a mental or physical handicap or a physical disfigurement

A positive endnote. This is a list of general life stressors which could contribute to clinical depression. However it is to be noted that most people when exposed to such “slings and arrows of outrageous fortune” do not succumb to depression; in the vast majority of cases it takes an interaction of genes predisposing one to depression in addition to the occurrence of these life stressors.

In the past decade or two much more clinical research has been conducted than in a comparable period in the past and lots of new helpful information is available. Today there are many scientifically based therapies including a panoply of anti-depressant medications and psychological interventions of various kinds e.g. cognitive behavioural therapy.

Given the array of tools in the therapist's arsenal against depression today, there is lots of hope that one can recover relatively quickly and completely from clinical depression. Depression no longer need be a lifelong debilitating condition. If you think you are depressed please see a professional for assessment and effective treatment. Help is available. Seek it out; there is lots of hope.


Written by:

Brian Scott

Dr. Scott is a clinical psychologist based in Singapore with three decades of counseling and psychotherapy experience in helping adults with many kinds of psychological difficulties. These include anxiety, depression, addictions (cybersex, love), and Adult Attention Deficit Hyperactivity Disorder (Adult ADHD).

Brian Scott belongs to Scott Psychological Centre in Singapore