Major Depressive Disorder

What is Major Depressive Disorder? | Symptoms | Risk Factors | Diagnostic Criteria | Course of Treatment | FAQ

Major Depressive Disorder (MDD), also referred to as Clinical Depression, is one of the most common forms of depression. It is characterised by long periods (at least 2 weeks) of extremely low moods and affects different aspects of life including sleep, appetite and behaviour. It should be noted that MDD is not the only form of depression;  there are different degrees to which people experience depression and different types of depression — do refer to the FAQ or Persistent Depressive Disorder (PDD) and Depression for more information.

Symptoms of MDD are similar to that of depression symptoms but are often at higher levels of severity and can include [1]:

• Feeling sad or having a depressed mood
• Loss of interest or pleasure in activities once enjoyed
• Changes in appetite — weight loss or gain unrelated to dieting
• Trouble sleeping or sleeping too much
• Loss of energy or increased fatigue
• Psychomotor agitation (which often manifests itself in observably restless behaviours like inability to sit still, pacing, handwringing) or Psychomotor retardation (ie. observably Psychomotor retardation (ie. observably slowed movements or speech). 
• Feeling worthless, guilty, or helpless
• Difficulty thinking, concentrating or making decisions
• Thoughts of death or suicide

Symptoms must last at least two weeks and must represent a change in your previous level of functioning for a diagnosis of depression.

It is also important to note that other medical conditions (e.g., thyroid problems, a brain tumour or vitamin deficiency) can mimic symptoms of depression so it is important to rule out general medical causes.

While there is no one cause for depression, research has shown that a variety of genetic, biological, environmental and psychological features contribute to an increased risk of MDD [2]:

• Family History of MDD
• Stressful situations or major life changes
• Past episodes of depression
• Co-occurring medical conditions e.g. cancer, diabetes, heart disease
  • Note: medication for these conditions may cause side effects that increase risk of MDD
• Lack of a support system
• History of physical or sexual abuse
• Childhood trauma
• Substance abuse (e.g., alcohol, drugs)

Major depressive disorder is characterised by distinct episodes lasting at least 2 weeks (although most episodes last considerably longer). Each episode is generally marked by stark changes in emotionality, cognitions, neurological capacity, and behaviour patterns. Diagnosing an individual based on a single episode is possible, but most cases are generally characterised by recurrent episodes [3].

These are the guidelines according to the DSM-5  to be clinically diagnosed with MDD [3]:

A. Five (or more) of the following symptoms have been present during the same 2-week period and represent a change from previous functioning: at least one of the symptoms is either (1) depressed mood or (2) loss of interest or pleasure.

Note: Do not include symptoms that are clearly attributable to another medical condition.

1. Depressed, low mood most of the day, nearly every day as indicated by either subjective report (e.g., feels sad, empty, hopeless) or observation made by others (e.g., appears tearful). (Note: In children and adolescents, it can be an irritable mood.)
2. Markedly diminished interest or pleasure in all, or almost all activities, most of the day, nearly every day (as indicated by either subjective account or observation).
3. Significant weight loss when not dieting or weight gain (e.g. a change of more than 5% of body weight in a month) or increase or decrease in appetite nearly every day (Note: In children consider failure to make expected weight gains)
4. Insomnia or hypersomnia nearly every day
5. Psychomotor agitation or retardation (e.g. slowing down of thought and a reduction of physical movement) nearly every day (observable by others, not merely subjective feelings of restlessness or being slowed down)
6. Fatigue or loss of energy nearly every day
7. Feelings of worthlessness or excessive or inappropriate guilt (which may not be accurate) nearly every day (not merely self-reproach or guilt about being sick)
8. Diminished ability to think or concentrate, or indecisiveness, nearly every day (either by subjective account or as observed by others).
9. Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide

B. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. 

C. The episode is not attributable to the physiological effects of a substance or to another medical condition.

D. The occurrence of the major depressive episode is not better explained by other psychotic disorders.

E. There has never been a manic episode or a hypomanic episode (see bipolar disorder).

Note: This exclusion does not apply if all of the manic-like or hypomanic-like episodes are substance-induced or are attributable to the physiological effects of another medical condition.

MDD can be treated by both psychotherapy (or counselling) and medication. Research has shown that a combination of psychotherapy and antidepressants are effective in treatment for people with chronic or severe MDD [4].

Medication

Some commonly used antidepressants include:

• Selective serotonin reuptake inhibitors (SSRI)
• Selective serotonin noradrenaline reuptake inhibitors (SSNRI)
• Tricyclic Antidepressants (TCA)
• Monoamine Oxidase Inhibitors (MAOIs)

Psychotherapy and Counselling

Since depressive disorders affect aspects of emotional functioning, therapies which address these issues are especially helpful. The following are some examples of the therapies and how it helps people with depression.

• Cognitive Behavioural Therapy

  Focuses on how the interaction between our thoughts, behaviour and feelings contribute to symptoms of MDD. Through CBT, clients learn to identify negative thought patterns and behaviours and replace them with something more helpful [5].

• Psychodynamic Therapy

  Examines emotional conflicts in relation to childhood experiences and seeks to improve insight through self-reflection and self-examination.

• Mindfulness-based Cognitive Behavioural Therapy

  Encourages self-monitoring and coping with daily negative emotions, to maintain an overall state of wellness [6].  

• Interpersonal Psychotherapy

  Focuses on how difficulties with interpersonal relations contribute to the symptoms of MDD. It involves identifying difficulties in personal relationships and targeting them to improve social relationships, which is a strong protective factor against the onset and worsening of mental health disorders [7].  

• Activity Scheduling

  A behavioural treatment for depression where clients identify and engage in activities they enjoy and monitor their mood while doing these activities. As clients may withdraw from activities they used to enjoy due to their depressed mood, activity scheduling aims to re-engage clients and improve their moods through the process [8].