Posted by: jedwardswright | August 25, 2011

Is Depression an Illness?

In recent times many conditions, such as alcoholism and depression, which once were considered to be character flaws and a lack of willpower have been rebranded as illnesses. Still, many people are of the opinion that if depressed people would quit complaining and think positive thoughts they would be fine.

Who is right? What is the evidence for the medical professions’ switch to diagnosing depression as an illness?

1.       Genetics and Depression

a.       Clinical studies of families, including specific research centered on twins and adoptees, have consistently and reliably shown that genetic factors play a major role in causing depression.

b.      Other contributing factors include childhood trauma and the adverse effect of current negative circumstances, but these issues play a lesser role.

c.       Gender differences in depression may also indicate a genetic pattern. Men tend to become depressed after experiencing separation, divorce or work difficulties. Women become depressed about events within their social circle, such as interpersonal problems, serious illness or death. However, a case could be made for the impact of gender-based socialization producing this effect.

2.       Cortisol and Depression

a.       Corticotropin-releasing hormone (CRH), which is associated with stress, has been found in higher levels in people with major depressive disorder.  The presence of CRH in the brain causes cortisol to be released into a person’s blood. Many symptoms of depression are also symptoms of excess cortisol in the body.

b.      Childhood trauma can permanently alter a body’s stress response. The prevalence of post-traumatic stress disorder (PTSD) in veterans who have been in harm’s way may suggest that severe adult trauma could provoke a similar reaction.

3.       The Monoamine-Deficiency Theory

a.       This theory suggests that depression is the result of a lack of certain neurotransmitters, namely serotonin, norepinephrine and dopamine, in the body’s nervous system. The job of neurotransmitters is to send messages along the nerve pathways to the rest of the body. Medications which have successfully treated MDD all increase one or more of these neurotransmitters in the brain.

Basically, there is evidence that strongly suggests major depressive disorder is caused by an imbalance in brain chemicals.

4.       Brain Structure and Depression

a.       New technologies such as structural imaging (e.g. MRI) show great promise for further evidence of differences in the brains of depressed individuals. So far, through structural, functional and post-mortem studies researchers have shown differences from the general population in one region of the brains of people with MDD. Yes, there is evidence that our brains are not the same as those of people without depression!

b.      Patients undergoing electrical stimulation in that area of the brain have demonstrated an improvement in symptoms of depression.

c.       It appears that over time, there are further changes in the brains of people with recurring, untreated depression.  Here is the biggest argument in favor of seeking early medical treatment for depression: it has the potential to prevent further deterioration in the condition of the brain!

5.       Sleep and Depression

a.       Sleep difficulties are common among people with depression. In fact, increased levels of depression during seasonal changes that disrupt sleep schedules are commonly known as seasonal affective disorder (SAD). Using light therapy, changing sleep patterns and sleep routines have been shown to reduce symptoms of depression in some people.

That sleep patterns are a factor in increasing or decreasing depression also indicates a likely physical cause for MDD.

Is depression an illness? If it was, we would expect to find physical differences in people with MDD that correlate to symptoms of depression, and we do.  Genetically, biochemically, structurally and in other aspects of our physiologies, people with major depressive disorder show differences from the general public.

There is consistent, concrete evidence that people with depression have a medical condition.


A Darker Shade of Blue is deeply indebted to the following article for information found in this post.


Hasler, Gregor. “Pathophysiology of Depression: Do We Have Any Solid Evidence of Interest to Clinicians?”







  1. This is pretty eye opening. Your research amazes me. I’m going back to read this again. Thank you.

    • KIm, you have such a gift of encouragement! I really appreciate your comments.

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