Depressive disorders

• Overview of depression

  Can be triggered by specific events or long-term circumstances • Not all people under high stress develop depression • Some cases have no clear environmental trigger
• Major Depressive Disorder (MDD)

  • Diagnosis criteria:

  • Two weeks of depressed mood or loss of interest/pleasure
  • At least four additional symptoms
• Prevalence and characteristics

  Accounts for about 1/3 of psychiatric hospital admissions in UK • 2-3 times more common in women than men • More frequent in lower socio-economic groups and young adults • Recurrent disorder (80% experience subsequent episodes) • Average of 4 episodes, typically lasting 3-4 months • 12% become chronic, lasting about 2 years
• Symptoms of MDD (ABCS)


  • Affective
  • Behavioral
  • Cognitive
  • Somatic
• Somatic:


  • Loss of energy
  • Sleep disturbances (insomnia or hypersomnia)
  • Weight changes
  • Diminished libido
• Cognitive:


  • Frequent negative thoughts
  • Low self-esteem
  • Suicidal thoughts
  • Irrational hopelessness
  • Difficulty concentrating and decision-making
• Behavioral:


  • Passivity
  • Lack of initiative
•  Affective:


  • Guilt, sadness
  • Lack of enjoyment in familiar activities
• Complex interaction of multiple factors:

  1. Biological factors (genetics, neurochemistry)
  2. Cognitive factors (schema, cognitive processing)
  3. Sociocultural factors (environmental stressors, cultural influences)
• Depression is not caused by a single factor but results from a combination of biological, cognitive, and social factors
• Major Depressive Disorder

  Major Depressive Disorder (MDD), is an affective / mood disorder, that is characterized by a persistent period of sadness (depressed mood) and a loss of interest in nearly all activities, along with other symptoms like changes in sleep, appetite, energy, concentration, or feelings of worthlessness. These symptoms cause noticeable distress or impairment in daily functioning.
• Symptoms of Major Depressive Disorder (ABC'S)


  1. Affective symptoms:
  2. Behavioral symptoms:
  3. Cognitive symptoms:
  4. Somatic symptoms:
• Affective symptoms:


  • Persistent feelings of sadness and guilt
  • Anhedonia (lack of pleasure in previously enjoyable activities)
• Behavioral symptoms:

  • Passivity
  • Lack of initiative
• Cognitive symptoms:


  • Frequent negative thoughts
  • Low self-esteem
  • Suicidal ideation
  • Irrational hopelessness
  • Difficulty concentrating
  • Indecisiveness
• Somatic symptoms:


  • Fatigue or loss of energy
  • Sleep disturbances (insomnia or hypersomnia)
  • Changes in appetite and weight
  • Decreased libido
• Diagnostic Criteria


  For a diagnosis of MDD, an individual must experience:

  • Two weeks of either depressed mood or loss of interest/pleasure
  • At least four additional symptoms from the list above
• Prevalence and Course


  • More common in women (2-3 times higher than in men)
  • Higher prevalence in lower socioeconomic groups
  • Most frequent among young adults
  • Recurrent disorder (80% experience subsequent episodes)
  • Average episode duration: 3-4 months
  • Average number of episodes: 4
  • Chronic in about 12% of cases (duration of about 2 years)
• The symptoms must cause significant distress or impairment in social, occupational, or other important areas of functioning.
• Etiological Factors


  MDD is believed to result from a complex interaction of multiple factors:

  1. Biological Factors:
  2. Cognitive Factors:
  3. Sociocultural Factors:
• Biological Factors:


  • Genetic predisposition
  • Neurochemical imbalances (e.g., serotonin, norepinephrine)
• Cognitive Factors:


  • Negative schemas
  • Maladaptive cognitive processing
• Sociocultural Factors:


  • Environmental stressors (e.g., chronic stress, traumatic events)
  • Cultural influences on expression and interpretation of symptoms
• Important Considerations

  1. Multifactorial nature: MDD is not caused by a single factor but results from a combination of influences.
  2. Individual differences: Not everyone exposed to similar risk factors will develop MDD, highlighting the importance of individual vulnerability.
  3. Stress-depression relationship: While stress can contribute to depression, not all individuals under high stress develop depressive disorders.
  4. Diagnostic challenges: Distinguishing between clinical depression and temporary low mood ("the blues") can be challenging for clinicians.