Depression: The Black Dog

Everybody goes through periods of sadness and low mood, especially after life-defining events like a breakup, the death of a loved one, or losing one’s job. But what differentiates normal “sadness” from pathological “depression”? We can determine this by looking at several different aspects, chiefly the duration and severity of the period of low mood, and the impact of the said low mood on normal daily routine.

A major depressive disorder is associated with depressed mood and/or loss of interest and pleasure in almost all activities, in addition to the presence of three or more of the following symptoms:

  • Significant weight or appetite disturbances
  • Insomnia or sedation
  • Loss of energy or fatigues
  • Feelings of worthlessness
  • Diminished ability to think, focus and make decisions
  • Recurrent thoughts of death, dying or suicide
  • Psychomotor retardation or agitation (a speeding or slowing of muscle movement)

In addition, the above symptoms must have been present for at least 2 weeks, with significant impact on function at work, school, social and interpersonal relationships. It is also important to note that drugs that cause depression should be ruled out, and symptoms should not be attributed to a recent bereavement or any such traumatic event.

Depressive symptoms often show up differently in different age groups. In teenagers, symptoms may include poor performance in school, self-harm and excessive recreational drug and alcohol use; whereas in older adults, they may complain of physical aches or pain, memory difficulties or personality changes, and general fatigue or sleep problems not caused by another medical conditions or medication. In men especially, complaints of fatigue, physical aches and pain, and sleep problems may be more common than a verbal admission of low mood.

The exact causes of depression are still unclear, but as with most mental disorders, several different factors may be involved. The most well-known cause of depression is neurochemical imbalances in the brain (particularly the lack of neurotransmitters such as serotonin and noradrenaline), and how they interact with brain circuits involved in maintaining mood stability. Depression is also thought to be caused or triggered by changes in the body’s balance of hormones, the most well-known example of this being post-partum depression (depression following childbirth). In addition, genetics also plays a role with depression being more common in people whose immediate relatives have this condition.

Major depressive disorder can be classified into mild, moderate and severe. The choice of treatment will depend on the severity of depression and can be divided into two approaches – pharmacological and non-pharmacological (without medication). Mild depression can be treated with talking therapy, either counselling or cognitive behavioural therapy. Moderate to severe depression usually has to be treated with a combination of medication and talking therapy.

Several classes of medications are used to treat depression. Most of them work via different mechanisms to increase levels of noradrenaline and serotonin in the brain, which as previously mentioned become imbalanced in people with depression. Typically, guidelines state that antidepressants must be taken at an adequate therapeutic dose for at least 2-4 weeks before benefit can be seen. Thus, one should not expect depression to be immediately cured following the use of these medications. Currently, the most commonly prescribed antidepressants are selective serotonin reuptake inhibitors (SSRIs), serotonin-noradrenaline reuptake inhibitors (SNRIs) and noradrenaline and specific serotonergic antidepressants (NASSAs). Selection of antidepressants depends on a variety of factors such as patient preference, target symptom profile, tolerability towards side effects (if any), cost and availability.

Winston Churchill is famously believed to have called depression “the black dog”, a state of pervasive and, persistent sadness. It is very real, and cannot just be written off by telling someone to focus on the positive, and think happy thoughts! Such flippant comments are not only unhelpful, they are dismissive of the genuine pain and suffering that a depressed person is going through. If you suspect that you or someone that you know is going through depression, please advise them to seek professional help. With proper treatment, depression is treatable and manageable.


1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders: DSM-5. Washington, D.C: American Psychiatric Association.

2. American Psychiatric Association. (2010). Practice Guideline for the Treatment of Patients with Major Depressive Disorder, 3rd edition. Washington, D.C: American Psychiatric Association.

3. Clinical Practice Guidelines for the Management of Major Depressive Disorder (2007). Ministry of Health Malaysia

4. Lin, SY & Stevens, MB. The Symptom Cluster-Based Approach to Individualize Patient-Centered Treatment for Major Depression. J Am Board Fam Med 2014: 27(1):151-159

5. National Institute for Health and Care Excellence. (updated 2016) Clinical Practice Guidelines. Depression in adults : recognition and management.

Laura Khoo Sui San
Laura Khoo Sui San

MPharm, BCPP , R.Ph

A Board Certified Psychiatric Pharmacist (BCPP) currently practising in Sentosa Psychiatric Hospital, MOH, Malaysia.


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