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Scale for the Assessment of Positive Symptoms-Parkinson's Disease (SAPS-PD)
Please visit this website for more information about the instrument: Scale for the Assessment of Positive Symptoms for Parkinson's Disease.
Supplemental - Highly Recommended: Parkinson's Disease (PD)
Recommendations for use: Indicated for studies requiring a measure of psychosis in PD.
Short Description of Instrument
The Scale for the Assessment of Positive Symptoms (SAPS) is a structured clinical interview originally designed to assess positive symptoms of schizophrenia falling into domains of hallucinations, delusions, bizarre behavior, and positive formal thought disorder (Andreasen, 1984). The SAPS has been used in Parkinson's Disease populations and is a recommended scale for use in Parkinson's Disease Psychosis (PDP) by a Movement Disorder Society Task Force in 2008 based on its use in studies of PD and its satisfactory clinimetric assessment albeit not in PD populations (Fernandez et al.). The SAPS- PD is a shortened version of the original SAPS scale which includes a subset of questions from the hallucinations and delusions domains (SAPS-H+D) indicative of those symptoms most commonly seen in a PDP patient population (Voss et al., 2013).
Comments/Special Instructions
The SAPS-PD is a shortened version of the SAPS that consists of 9-items from the SAPS-H+D domains (Auditory hallucinations, Voices conversing, Somatic or tactile hallucinations, Visual hallucinations, Global rating of severity of hallucinations, Persecutory delusions, Delusions of jealousy, Delusions of reference, and Global rating of severity of delusions) (Voss et al., 2013).
Scoring and Psychometric Properties
Scoring: Each item is scored on a scale of 0-5:
0 = None/None at all
1 = Questionable
2 = Mild
3 = Moderate
4 = Marked
5 = Severe
The sum of the 9 items (4 hallucination plus 1 global hallucination items; 3 delusion plus 1 global hallucination items) produces a total score of 0-45.
Psychometric Properties: Psychometric properties are not available in PD.
The SAPS-PD measures the symptoms most relevant from the SAPS in PDP: hallucinations and delusions. Although the full 34 item SAPS was shown to be sensitive to change in Parkinson's Disease Psychosis (PDP) (Voss et al., 2010), it includes numerous items that are not relevant to the PDP population, such as bizarre behavior or positive formal thought disorder. The scale does not specifically assess presence and passage hallucinations and illusions; however, these are likely assessed as part of the global assessment of hallucinations.
In a retrospective analysis of three large clinical trials in a PDP population which utilized the SAPS, only 5 hallucination items and 4 delusion items occurred at a frequency greater than 10%. These 9 items were used in the construction of the SAPS-PD scale (Voss et al., 2013).
Strengths: The SAPS-PD may be sensitive to change in clinical trials for PD psychosis.
Weaknesses: The SAPS-PD requires a trained clinical interviewer that may not be conducive to some settings. The SAPS-PD is not designed to assess the full spectrum of psychotic features in PDP such as presence and passage hallucinations, and illusions. The SAPS-PD may not appropriate for use in those with dementia. No psychometric properties are available in PD.
Key Reference:
Voss T, Bahr D, Cummings J, Mills R, Ravina B, Williams H. Performance of a shortened Scale for Assessment of Positive Symptoms for Parkinson's disease psychosis. Parkinsonism Relat Disord. 2013 Mar;19(3):295-9
Additional References:
Fernandez HH, Aarsland D, Fenelon G, Friedman JH, Marsh L, Troester AI, Poewe W, Rascol O, Sampaio C, Stebbins GT, Goetz CG.  Scales to Assess Psychosis in Parkinson's Disease. Mov Disord. 2008 Mar 15;23(4):484-500.
Voss TS, Brocht AF, Ravina B. Performance of the scale for assessment of positive symptoms in Parkinson's disease psychosis. Mov Disord. 2010 Jan 15;25(1):124-5
Document last updated August 2022