Validation of the Short Version of the Panic Agoraphobic Spectrum (PAS-SV) Questionnaire.

Objective: a spectrum model of psychopathology has allowed, in recent years, to recognize the subclinical or sub-threshold symptomatology that may be associated with full-blown mental disorders. The conceptualization of a panic - agoraphobic spectrum was developed in consideration of the substantial clinical heterogeneity revealed by studies on panic disorder with or without agoraphobia. The current study aims to determine the psychometric properties of the Panic Agoraphobic Spectrum - Short Version (PAS-SV), a new questionnaire designed to identify the spectrum of panic - agoraphobic symptoms.

Method: 42 subjects with panic disorder or agoraphobia (PAD) according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), 41 subjects with autism spectrum disorder (ASD), and 60 healthy controls (HC) were recruited from the Psychiatric Clinic of the University of Pisa and assessed with the SCID-5, the Panic Disorder Severity Scale (PDSS) and the PAS-SV.

Results: PAS-SV demonstrated a high level of internal consistency and the test-retest reliability for total and domain scores was excellent. PAS-SV domain scores were positively and significantly correlated with each other (p < 0.001), with Pearson's coefficients ranging from 0.771 to 0.943. All the PAS-SV domain scores were highly correlated with the PAS-SV total score. The correlation coefficients between PAS-SV and alternative measures of panic - agoraphobic symptoms appeared all significant and positive. Significant differences among diagnostic groups on both PAS-SV domains and total scores were found. PAS-SV total score increased significantly and progressively from HC, to the ASD up to the PA group.

Conclusions: The PAS-SV showed excellent internal consistency and test-retest reliability and strong convergent validity with alternative dimensional measures of PA. The questionnaire performed differently among the three diagnostic groups, with an increasing score gradient from HC to patients with ASD to the PA group.