A chronic form of depression with persistent low mood
1. Definition & Diagnostic Criteria (DSM-5)
PDD requires:
✅ Depressed mood for most of the day, for more days than not
✅ Duration ≥2 years in adults (≥1 year in children)
✅ Plus ≥2 of these symptoms:
• Poor appetite/overeating
• Insomnia/hypersomnia
• Low energy/fatigue
• Low self-esteem
• Poor concentration
• Feelings of hopelessness
Key Distinction from MDD:
- Less severe but more chronic symptoms
- No more than 2 months symptom-free during the duration
2. Clinical Presentation
| Feature | PDD | MDD |
|---|---|---|
| Mood | Persistent low-grade sadness | Intense episodic despair |
| Functioning | “Functional but miserable” | Acute impairment |
| Self-View | “I’ve always been this way” | “This isn’t like me” |
| Onset | Insidious (early adulthood) | More abrupt |
High-Risk Groups:
• Those with childhood adversity
• First-degree relatives with mood disorders
3. Causes & Risk Factors
| Category | Contributors |
|---|---|
| Biological | • Chronic HPA axis hyperactivity • Reduced hippocampal volume |
| Psychological | • Early maladaptive schemas • Learned helplessness |
| Social | • Long-term stressors (poverty, caregiving) |
Myth Buster:
❌ “Just personality” → Biological markers distinguish it from temperament
4. Diagnosis Challenges
Differential Diagnosis:
• MDD in partial remission
• Adjustment disorder with depressed mood
• Personality disorders (e.g., avoidant PD)
Assessment Tools:
• Chronic Depression Questionnaire
• Hopkins Symptom Checklist
5. Treatment Approach
A. Pharmacotherapy
• SSRIs/SNRIs: Same as MDD but often require longer trials (10-12 weeks)
• Considerations: Lower doses may suffice due to sensitivity
B. Psychotherapy
• Cognitive Behavioral Analysis System of Psychotherapy (CBASP): Specifically developed for chronic depression
• Mindfulness-Based CBT: Targets rumination
C. Lifestyle Modifications
• Regular activity scheduling (combats inertia)
• Social rhythm therapy (stabilizes daily patterns)
6. Prognosis
• 50% develop superimposed MDD episodes (“double depression”)
• Good response to combined treatment (60-70% improve)
• Relapse prevention requires maintenance therapy
7. Special Considerations
| Population | Clinical Notes |
|---|---|
| Elderly | Often misattributed to “normal aging” |
| Adolescents | High risk of progressing to MDD |
| Perfectionists | May not recognize impairment |
8. Patient Support Strategies
✅ Validate chronic struggle (“This has been with you a long time”)
✅ Small incremental goals (avoid overwhelming expectations)
✅ Psychoeducation about neuroplasticity (hope for change)