Calgary Depression Scale for Schizophrenia (CDSS)
9-item clinician-rated scale designed to separate depressive symptoms from negative or extrapyramidal symptoms in schizophrenia (Addington 1993). Each item 0–3, total 0–27. A score above 6 (≥ 7) indicates clinically significant depression.
Score interpretation
CDSS 0–6 — no clinically significant depression
→ Continue antipsychotic plan. Monitor at next review.
CDSS ≥ 7 — consistent with a major depressive episode; higher totals, more severe
→ Add SSRI (sertraline / citalopram) — avoid fluvoxamine if on clozapine. Optimise antipsychotic (consider aripiprazole or quetiapine). CBTp. If severe: Active suicide risk assessment. SSRI + crisis plan. Hospital admission if active suicidality. Consider ECT if severe / catatonic / treatment-resistant. Specialist psychosis review.
Interpretation bands for the CDSS. Apply clinical judgement and local guidance.
References
Related
Curated clinical cross-links plus same-class fallbacks.
- Lamotrigine (Psychiatric Use) · Mood Stabiliser (Sodium Channel Blocker) — Bipolar Depression
- Lumateperone · Atypical Antipsychotic — Multimodal (Schizophrenia / Bipolar Depression)
- Sodium Valproate · Antiepileptic / Mood stabiliser
- Valproic acid · Antiepileptic / mood stabiliser
- Risperidone (Paediatric) · Atypical Antipsychotic — Autism Spectrum Disorder / Schizophrenia / Tic Disorders
- Lithium Carbonate · Mood stabiliser
- Acute Behavioural Disturbance / Rapid Tranquillisation · RCEM 2022; RCPsych 2022; NICE NG10
- Self-Harm Presentation · NICE NG225 (2022)
- Capacity Assessment (Mental Capacity Act) · MCA 2005; Code of Practice
- Acute Psychosis Management · NICE CG178 2014
- Depression Management · NICE CG90 2022
- Lithium Therapy Monitoring · NICE CG185
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.