Assessing the severity of depression in patients with schizophrenia.
Differentiating depressive symptoms from negative symptoms (e.g., apathy, flat affect) and extrapyramidal side effects (EPS).
Monitoring response to antidepressant augmentation in schizophrenia.
Identifying suicide risk in patients with psychotic disorders.
Section 2
Formula & Logic
Scoring Component
The CDSS consists of 9 items: Depressed Mood, Hopelessness, Self-depreciation, Guilty Ideas of Reference, Pathological Guilt, Morning Depression, Early Wakening, Suicide, and Observed Depression. Each is rated from 0 (absent) to 3 (severe).
Diagnostic Thresholds
Score > 5
Suggested cutoff for Major Depressive Disorder
Sensitivity / Specificity
High (specifically designed to avoid negative symptom overlap)
Section 3
Pearls/Pitfalls
Differentiating Symptoms
Unlike the HAM-D or BDI, the CDSS excludes somatic symptoms (like weight loss or motor retardation) which can be confounded by antipsychotic side effects or negative symptoms of schizophrenia.
Clinical Pearls
Depression in schizophrenia is a primary risk factor for suicide; a high score on Item 8 (Suicide) warrants immediate safety planning.
The CDSS is valid in both the acute and stabilized phases of schizophrenia.
If negative symptoms predominate (e.g., alogia, avolition) but the CDSS score is low, focus on optimizing antipsychotic therapy rather than adding antidepressants.
Section 4
Next Steps
Next Steps
01
Score > 5: Evaluate for comorbid MDD. Consider SSRI or SNRI augmentation if the patient is on stable antipsychotic therapy.
02
High Suicide Score: Immediate risk assessment. Distinguish between "command hallucinations" to harm self and "depressive" suicidal ideation.
03
Longitudinal Follow-up: Repeat CDSS monthly during the start of new treatments to quantify improvement.
Section 5
Evidence Appraisal
Primary Reference
A depression rating scale for schizophrenics
Addington D et al. • Schizophrenia Research. 1990;Vol 3, Issue 4. pp. 247-251. The original validation study.
Section 6
Literature
Donald Addington
Developed by Dr. Donald Addington and colleagues at the University of Calgary. It has become the gold standard tool for assessing depression in the context of psychotic illness.
