Italian validation of the Sleep Condition Indicator: A clinical screening tool to evaluate Insomnia Disorder according to DSM-5 criteria.
OBJECTIVE
The present study investigated the validity, reliability and, as novel aspects, the temporal stability and discriminant validity of the Italian version of the Sleep Condition Indicator (SCI), a new brief tool to appraise Insomnia Disorder (ID) according to the new criteria of the DSM-5.


METHODS
Subjects with ID (DSM-5), Obstructive Sleep Apnea Syndrome (OSAS) (ICSD3) and a group of healthy subjects (H) were recruited. At the first evaluation (T1), SCI, the Insomnia Severity Index (ISI) and the Pittsburgh Sleep Quality Index (PSQI) were administered. ID patients also completed the SCI 2months later (T2). Statistical analyses included Cronbach's alpha co-efficient calculation, Intraclass Correlation, Receiver Operating Characteristic (ROC) curves and Pearson correlations.


RESULTS
Eighty-eight ID (n=50 F, mean age 49.9±15.1 years), 43 OSAS (n=22 F, mean age 50.2±9.1 years) and 40 H (n=22 F, 49.3±13 years) were recruited at T1. SCI, PSQI and ISI scores were significantly higher in the ID group vs H and OSAS (both p<.001). ROC analysis revealed cut off of >18 to correctly identify 100% of H, cut off of >17 the 100% of OSAS and <17 the 100% of ID. Cronbach's alpha were 0.71 at T0, 0.78 at T2 for ID, 0.76 and 0.81 respectively for H and OSAS. SCI showed a negative correlation with ISI (p<.01) and PSQI (p<.05).


CONCLUSIONS
The Italian version of SCI shows good internal consistency, temporal stability and concurrent validity in insomnia, confirming data on the original version. Importantly, the present study shows that the SCI effectively discriminates insomnia from both normal sleep and OSAS.
Sleep Disorder Clinic, Department of Clinical Experimental Medicine, Psychiatric Unit, University of Pisa, Pisa Italy. Electronic address: lpalagini@tiscali.it.
Laura
L
Palagini
Unit of Sleep Medicine, National Neurological Institute C. Mondino Pavia, Italy.
Gloria
G
Ragno
Sleep Disorder Clinic, Department of Clinical Experimental Medicine, Psychiatric Unit, University of Pisa, Pisa Italy.
Lisa
L
Caccavale
Sleep Disorder Clinic, Department of Clinical Experimental Medicine, Psychiatric Unit, University of Pisa, Pisa Italy.
Alessia
A
Gronchi
Unit of Sleep Medicine, National Neurological Institute C. Mondino Pavia, Italy.
Michele
M
Terzaghi
Sleep Disorder Clinic, Department of Clinical Experimental Medicine, Psychiatric Unit, University of Pisa, Pisa Italy.
Mauro
M
Mauri
Sleepio Limited, London, UK; Nuffield Department of Clinical Neurosciences/Sleep & Circadian Neuroscience Institute, University of Oxford, UK.
Simon
S
Kyle
Sleepio Limited, London, UK; Nuffield Department of Clinical Neurosciences/Sleep & Circadian Neuroscience Institute, University of Oxford, UK.
Colin A
CA
Espie
Unit of Sleep Medicine, National Neurological Institute C. Mondino Pavia, Italy.
Raffaele
R
Manni
D000328:Adult; D000368:Aged; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011594:Psychometrics; D012372:ROC Curve; D015203:Reproducibility of Results; D012891:Sleep Apnea Syndromes / Q000175:diagnosis*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis*; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires
Chronic insomnia; Diagnosis; Discriminant tool; Evaluation