Depression
Definition
- Depression (Major Depressive Disorder, MDD) is a common mood disorder characterised by persistent low mood, anhedonia (loss of interest), and fatigue, along with cognitive, emotional, and somatic symptoms.
- Episodes typically last ≥2 weeks and significantly impair daily functioning.
Causes & Risk Factors
Pathophysiology
- Monoamine Hypothesis → ↓ Serotonin, Dopamine, Noradrenaline → Depressed Mood, Anhedonia, Fatigue.
- Dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis → ↑ Cortisol Levels (Chronic Stress Response).
Structural Brain Changes → Reduced Hippocampal Volume, Impaired Neuroplasticity.
Risk Factors for Depression
🔹 Depression arises from a combination of genetic, biological, and environmental factors.
Clinical Features
Symptoms of Depression (DSM-5 Criteria)
- At least 5 symptoms present for ≥2 weeks, including either (1) Depressed Mood or (2) Anhedonia.
|
Category |
Common Symptoms |
|
Core Symptoms |
Low Mood, Anhedonia, Fatigue. |
|
Cognitive Symptoms |
Poor Concentration, Feelings of Guilt or Worthlessness, Suicidal Thoughts. |
|
Somatic Symptoms |
Sleep Disturbances (Insomnia or Hypersomnia), Appetite Changes, Psychomotor Agitation or Retardation. |
|
Behavioural Symptoms |
Social Withdrawal, Self-Neglect, Poor Work Performance. |
Signs on Examination
|
Feature |
Description |
|
Low Affect & Sad Facial Expression |
Flat or Tearful Demeanour. |
|
Slow Speech & Movements |
Psychomotor Retardation. |
|
Poor Eye Contact |
Avoids Engagement. |
|
Self-Neglect |
Poor Hygiene, Dishevelled Appearance. |
🔹 Depression presents with persistent low mood, fatigue, cognitive impairment, and somatic symptoms.
Referral Criteria (NICE Guidelines)
Urgent Referral (If Severe Symptoms or Risk to Self/Others)
- Active Suicidal Ideation or Self-Harm.
- Severe Functional Impairment (Inability to Work, Self-Care Deficits).
- Psychotic Symptoms (Delusions, Hallucinations).
- Severe Agitation or Catatonia.
Routine Referral (If Symptoms Persist or Affect Functioning)
- Moderate-Severe Depression Unresponsive to First-Line Treatment.
- Recurrent Episodes or Significant Relapse Risk.
- Coexisting Complex Psychiatric Disorders (Bipolar, PTSD, OCD).
🔹 Severe cases require urgent psychiatric referral; mild-moderate cases can be managed in primary care.
Diagnosis
Clinical Diagnosis (DSM-5/ICD-10 Criteria)
“SIGECAPS-D” → Depression Diagnosis Checklist
Each letter corresponds to a key symptom:
- S → Sleep disturbances (Insomnia or Hypersomnia)
- I → Interest loss (Anhedonia) (Loss of pleasure in activities)
- G → Guilt or Worthlessness (Excessive self-blame)
- E → Energy loss (Fatigue) (Persistent exhaustion)
- C → Concentration problems (Difficulty focusing, indecisiveness)
- A → Appetite or weight changes (>5% change in a month)
- P → Psychomotor changes (Agitation or Retardation)
- S → Suicidal thoughts or behaviours (Recurrent thoughts of death)
- D → Depressed mood (Most of the day, nearly every day)
Differential Diagnosis
|
Condition |
Key Differences |
|
Bipolar Disorder (Depressive Episode) |
History of Manic or Hypomanic Episodes. |
|
Generalised Anxiety Disorder (GAD) |
Persistent Worry Without Anhedonia. |
|
Schizoaffective Disorder |
Psychotic Features Persist Outside Mood Episodes. |
|
Hypothyroidism |
Fatigue, Weight Gain, Cold Intolerance. |
🔹 Depression is diagnosed clinically, but medical causes (e.g., hypothyroidism) should be excluded.
Assessment:
Hospital Anxiety and Depression (HAD) scale and the Patient Health Questionnaire (PHQ-9).
- a score < 16 on the PHQ-9: less severe depression
- a score of ≥ 16 on the PHQ-9: severe depression
Management (NICE Guidelines)
Stepwise Approach to Depression Management
|
Step |
Intervention |
|
Step 1 (Watchful Waiting – If Symptoms Are Mild & Short-Term) |
Psychoeducation, Lifestyle Changes, Self-Help. |
|
Step 2 (Low-Intensity Psychological Therapy – First-Line for Mild-Moderate Depression) |
Cognitive Behavioural Therapy (CBT), Behavioural Activation, Mindfulness. |
|
Step 3 (Pharmacological Therapy – If Psychological Therapy Insufficient) |
SSRI (Sertraline, Fluoxetine First-Line). |
|
Step 4 (Specialist Referral – If Severe or Treatment-Resistant) |
Psychiatry, Crisis Team, Electroconvulsive Therapy (ECT) If Severe. |
First-Line Pharmacological Treatment (If Needed)
|
Drug |
Mechanism |
Considerations |
|
Sertraline (SSRI, First-Line) |
Increases Serotonin Levels. |
Start Low, Increase Gradually, Takes 4-6 Weeks to Work. |
|
Fluoxetine (Alternative SSRI, Preferred in Adolescents) |
Same as Sertraline. |
Longer Half-Life, Fewer Withdrawal Effects. |
|
Mirtazapine (Noradrenergic & Serotonergic Antidepressant, Second-Line) |
Sedative Effects – Good for Insomnia & Poor Appetite. |
Weight Gain Common. |
|
Venlafaxine (SNRI, If SSRIs Are Ineffective) |
Affects Serotonin & Noradrenaline. |
Avoid in Hypertension (↑ BP). |
|
Amitriptyline (TCA, Reserved for Severe Cases) |
Potent Sedative & Analgesic Effects. |
More Side Effects, Risk of Overdose. |
🔹 SSRIs are first-line; TCAs and MAOIs are used in treatment-resistant cases.
Lifestyle & Psychological Interventions
- Exercise & Sleep Hygiene.
- Social Support & Structured Routine.
- CBT for Negative Thought Patterns.
🔹 Psychological therapy is key for long-term recovery.
Prognosis & Complications
Prognosis
|
Condition |
Outcome |
|
Mild Depression (With Therapy) |
Good Recovery. |
|
Recurrent Depression (Without Treatment) |
High Risk of Chronicity. |
Complications of Depression
|
Complication |
Features |
|
Suicide Risk |
Highest in Untreated or Severe Depression. |
|
Substance Abuse |
Self-Medication with Alcohol or Drugs. |
|
Cardiovascular Disease |
Increased Risk Due to Chronic Stress. |
🔹 Early treatment improves prognosis and reduces suicide risk.
UKMLA Key Points
- Best first-line treatment for mild-moderate depression: CBT.
- Best first-line pharmacological treatment: Sertraline (SSRI).
- When to refer urgently: Suicidal ideation, severe functional impairment.
Best treatment for treatment-resistant depression: Electroconvulsive Therapy (ECT).