Psychotic Depression: Symptom Severity
Vol. 3 #3
Standard measures for the assessment of the severity of depression may not be valid in tracking psychotic depression. A group of researchers from Denmark and Belgium led by Dr. Søren D. Østergaard have created a rating scale specifically to address this problem. They developed the Psychotic Depression Assessment Scale (PDAS). The researchers combined the six items from the melancholia subscale of the Hamilton Depression Rating Scale (HAM-D6) and five items from The Brief Psychiatric Rating Scale.
The authors note that the HAM-D17 has limitations with regard to validity when compared to clinical global severity measures. The HAM D17 is not unidimensional. Changes which in fact represent side effects of medication can be reflected as improvement in symptoms eg. weight gain or increased sleeping may represent side effects rather than improvement in depressive symptoms.
The HAM-D6 is unidimensional, has greater clinical validity and is more sensitive to core symptom changes.
The Psychotic Depression Assessment Scale, covers some of the core features of psychotic depression.
The scale items consist of the following:
- Somatic symptoms : fatigue, muscle pains or aches
- Work and activities
- Depressed mood ranging from slight sadness to severely depressed with feelings of hopelessness and/or depressive delusions.
- Psychic anxiety: worrying, tension or fear.
- Guilt feelings which at the severe end of the spectrum are delusional.
- Psychomotor retardation
- Emotional withdrawal: lack of emotional engagement, limited verbal responses.
- Suspiciousness: ranging from little preoccupation to delusional elaboration.
- Hallucinations ranging from occasional to persistent.
- Unusual thought content: delusions.
- Blunted affect: diminished emotional range monotone voice.
Each item is rated from 0 to 4:
The cut-off scores for remission, mild, moderate, and severe PD were determined using the Clinical Global Impression – Severity Scale (CGI-S) as reference by means of pair-wise receiver operating characteristic (ROC) analyses. In one study using the PDAS differentiated treatment with Olanzapine+Sertraline which had significantly better outcomes than Olanzapine+Placebo (p<0.001).
Vermeulen T, Lemey L, Van Diermen L, Schrijvers D, Madani Y, Sabbe B, Van Den Bossche MJA, van der Mast RC, Østergaard SD. Clinical validation of the Psychotic Depression Assessment Scale (PDAS) against independent global severity ratings in older adults. Acta Neuropsychiatr. 2018 Mar 4:1-6. doi: 10.1017/neu.2018.2. [Epub ahead of print] PubMed PMID: 29501075.
Köse Çinar R, Østergaard SD. Validation of the semi-structured PsychoticDepression Assessment Scale (PDAS) interview. Acta Neuropsychiatr. 2017 May 24:1-6. doi: 10.1017/neu.2017.15. [Epub ahead of print] PubMed PMID: 28535843.
Østergaard SD, Rothschild AJ, Flint AJ, Mulsant BH, Whyte EM, Vermeulen T, Bech P, Meyers BS. Establishing the cut-off score for remission and severity-ranges on the Psychotic Depression Assessment Scale (PDAS). J Affect Disord. 2016 Jan 15;190:111-114. doi: 10.1016/j.jad.2015.09.073. Epub 2015 Oct 22PubMed PMID: 26496016; PubMed Central PMCID: PMC4685000.
Østergaard SD, Rothschild AJ, Flint AJ, Mulsant BH, Whyte EM, Leadholm AK, Bech P, Meyers BS. Rating scales measuring the severity of psychotic depression. Acta Psychiatr Scand. 2015 Nov;132(5):335-44. doi: 10.1111/acps.12449. Epub 2015 May 27. Review. PubMed PMID: 26016647; PubMed Central PMCID: PMC4604003.
Park SC, Østergaard SD, Choi J, Kim JM, Jun TY, Lee MS, Kim JB, Yim HW, Park. Is the BPRS-5 subscale of the psychotic depression assessment scale a reliable screening tool for psychotic depression?: Results from the CRESCEND study. J Affect Disord. 2015 Mar 15;174:188-91. doi: 10.1016/j.jad.2014.11.014. Epub 2014 Dec 1. PubMed PMID: 25506755.