What is Depression?

Depression comprises a set of symptoms such as depressed mood and loss of interest in activities that must persist almost every day for at least two weeks (to be diagnosed as having MDD). This is in contrast to the everyday mood fluctuations and negative emotions that arise from everyday life’s experiences. These symptoms often greatly affect one’s daily functioning, interactions with people, and accomplishment of tasks [1].

Depression is a mood disorder that includes various subtypes of depressive disorders such as:

It is one of the most common and widely known mental disorders worldwide, affecting more than 264 million people [2].

Common Signs & Symptoms of Depression

According to the World Health Organisation, a depressive episode is characterised by a loss of pleasure or interest in activities and depressed moods (i.e., feeling sad, irritable, empty), for most of the day, nearly every day, for at least two weeks. During a depressive episode, the person experiences significant difficulty in their daily functioning, affecting their relationships, work and personal life, and/or other important areas of functioning. A depressive episode can be categorised as mild, moderate, or severe depending on the number and severity of symptoms, as well as the impact on the individual’s functioning [4​​].

Additionally, several other symptoms may also be present:

  • Poor concentration
  • Feelings of excessive guilt or self-worthlessness
  • A sense of hopelessness regarding the future
  • Thoughts about dying or suicide
  • Disrupted sleep
  • Changes in eating patterns or weight
  • Feeling especially lethargic or low in energy

For some, symptoms of a depressive episode may manifest as bodily symptoms such as experiencing pain, fatigue and weakness, that are not due to another medical condition.

Causes & Risk Factors of Depression

According to The Diagnostic and Statistical Manual of Mental Disorders (DSM-V), depression is believed to be caused by a combination of genetic, biological, environmental, and psychological factors, including [3]:

  • Personal or family history of depression
  • Adverse childhood experiences, or stressful life events 
  • Certain physical illnesses and medications

Treatment of Depression

Treatment for depressive disorders includes both medication and non-pharmacological approaches such as psychotherapy. Most research has shown that combined treatment (medication and psychotherapy) is the most effective course of treatment, compared to standalone pharmacological approaches [5].  

Medication

Pharmacological management generally includes antidepressants such as [6]:

  • Selective serotonin reuptake inhibitors (SSRIs)
  • Serotonin-noradrenaline reuptake inhibitors (SNRIs)
  • Tricyclic Antidepressants (TCAs)
  • Monoamine Oxidase Inhibitors (MAOIs)

SSRIs and SNRIs are second-generation antidepressants that are more commonly prescribed due to their more manageable side-effects compared to TCAs and MAOIs, the first-generation antidepressants. 

Therapy Treatments

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

  • Cognitive Behavioural Therapy (CBT)

    CBT looks into the links between thoughts, emotions and behaviour. It aims to alleviate distress by identifying, interrupting and correcting negative thought patterns and learned unhelpful behavioural responses, and equipping patients with more adaptive mindsets and behaviours [7, 8].

  • Psychodynamic Therapy

    It examines emotional conflicts in relation to childhood experiences and seeks to improve insight through self-reflection and self-examination [9].

  • Emotion-focused Therapy

    This therapy type focuses on becoming aware, identifying, accepting and understanding to better manage their emotions more flexibly — by facing negative emotions and transforming them to take on a more positive meaning [10].

  • Acceptance and Commitment Therapy (ACT)

    ACT is an action-oriented approach to psychotherapy that stems from traditional behaviour therapy and cognitive behavioural therapy. It aims to improve functioning and quality of life by increasing psychological flexibility, defined as being able to act effectively, to live in line with one’s values, while accepting the presence of distressing or interfering thoughts, emotions and bodily sensations [11].

  • Dialectical Behavioural Therapy (DBT)

    DBT is designed to facilitate the learning of new skills, the embedding of these skills into the individual’s repertoire, and the generalisation of these skills across contexts. DBT incorporates a range of change-enhancing strategies interwoven with acceptance-focused strategies [12].

FAQ

Experiencing significant loss especially of a loved one can be extremely devastating. Bereavement and grief in response to that loss may appear to resemble symptoms of a depressive episode, but it does not necessarily lead to an episode of major depressive disorder [3]. To distinguish between the two, the following table may be helpful:

Bereavement
Major Depressive Episode
Pattern Experienced in periodic waves that become less frequent and severe over time, as the individual learns to manage their feelings of yearning and pain. ​​Experienced more as an underlying, prolonged season of negative emotions.
Emotional Focus  Feelings of emptiness, disorganization, yearning, and grief regarding the deceased’s absence.  The individual has the capacity to still enjoy community, hobbies, and pleasant emotions when not thinking about the deceased. Pervasive depressed mood and the loss of capacity to feel pleasure or allow oneself to enjoy moments.
Self-esteem Typically preserved, but self-loathing usually centres around regret for not having done more, or failing to intervene (e.g., not visiting the deceased more often, failing to communicate their love enough to the deceased). Fundamental sense of identity and self-worth is poor; not targeted to one area or trigger. The individual is usually critical toward themselves, and often questions their belonging to the world or their communities. 
Sociability While this is dependent on individual grieving patterns, bereaved individuals’ perception of community and social relationships remain preserved. Most are able to maintain connections with close family and friends. Feels a deep sense of displacement and disengagement from community, leading to withdrawal behaviours not just temporarily, but for prolonged periods of time. Depressed individuals also tend to feel the impulse to cut ties even with close friends and family.  
Thoughts Thoughts mainly focus on the deceased and memories of the deceased. Self-critical or pessimistic thoughts that are often a result of a culmination of experiences and hurt. 
Thoughts of death or suicide Thoughts of death and dying stem from a yearning to be reunited with the deceased. Thoughts of death and dying stem from feelings of helplessness, hopelessness, and worthlessness. In many cases, individuals at a high risk of suicide have self-justified that their deaths will not matter, and will be worth more to those around them than their lives. 
Triggers ​​Depressed mood triggered by thoughts or reminders of the deceased. Depressed mood does not have a clear trigger.

(Adapted from https://www.aafp.org/afp/2014/1115/p690.html)

According to DSM-V [3], when bereavement and an episode of depressive disorder do co-occur, one tends to experience greater functional impairments compared to bereavement without major depressive disorder.

Sadness is often perceived to be synonymous with depression. However, while sadness is one of the main symptoms of depression, it is not a necessary nor sufficient condition for one to be clinically diagnosed as having depression. In other words, one may experience sadness even without a diagnosis of depression, and sadness is not necessarily required for one to be clinically diagnosed with depression [13].

The criteria for one to be diagnosed as having a Major Depressive Episode requires meeting at least 5 of these symptoms among 9 including [13]:

  1. Weight variation
  2. Insomnia
  3. Psychomotor agitation or retardation
  4. Loss of energy
  5. Feelings of worthlessness
  6. Diminished concentration
  7. Recurrent thoughts of death
  8. And must include depressed mood or lost of interest or pleasure in almost all activities

In other words, one may be clinically diagnosed as having MDD even without experiencing feelings of sadness. The following table presents further differentiating symptoms between sadness and depression: 

Sadness
Depression
Triggers Usually has a clear trigger (e.g., loss of loved one or romantic breakup) Usually has no clear cause
Self-esteem Self-esteem generally preserved Underlying tones of guilt and/ or worthlessness that can culminate in suicidal thoughts
Activities Still able to find happiness and enjoyment in engaging in hobbies or things that they like Lack interest and/ or enjoyment in activities that used to be enjoyable (anhedonia)
Time frame  Temporal — Sense of guilt and worthlessness generally not permanent  Consistently low mood; frequent and long-lasting sense of worthlessness and guilt 

(Adapted from https://www.semanticscholar.org/paper/Grief%2C-Demoralization%2C-and-Depression%3A-Diagnostic-Strada/98b811ad5e7605ae60e446769d73fb08a2b3eebe)