Polysomnographic and psychometric correlates of napping in primary insomnia patients

Introduction: This study aims to evaluate napping in patients with insomnia compared with two control groups and to investigate the relationships between psychometric measures and napping habitude.Methods: Sixty-eight adult patients with chronic primary insomnia were enrolled; 27 men and 41 women, mean age 53.6 ± 13. All patients underwent 24 h ambulatory polysomnography (A-PSG). Prevalence of napping behavior in Insomnia Patients (I-group) was compared with Obstructive Sleep Apnea Syndrome (OSAS) patients (OSAS-group) and epilepsy patients (Ep-group). Patients were evaluated with Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Berlin Questionnaire. Psychometric evaluation included Self-Administered Anxiety Scale (SAS #54), Beck Depression Inventory (BDI), Maudsley's Obsessive Compulsive Inventory (MOCI), Snaith-Hamilton Pleasure Scale (SHAPS), and Eating Attitude Test (EAT-26).Results: No significant differences resulted in prevalence and duration of naps in the three groups. In the comparison between nappers (N+, subject with at least one nap in A-PSG) and non-nappers (N-, subject with no naps in A-PSG) we observed significant differences in PSQI scores (N+ = 14.1 ± 2.7; N- =11.9 ± 3.3; Whitney U-test = 341.0; p = 0.004) and in EAT score (N+ = 9.8 ± 9.7; N- = 4.4 ± 5.6; Whitney U-test = 313.5, p = 0.0.14); no significant differences were measured in other psychometric parameters and in sleep macrostructural indexes.Conclusions: Our data are in accordance with previous findings outlining that N + insomniacs have higher PSQI scores than N-. Our results do not confirm the suggested association between napping and depressive or obsessive-compulsive symptoms. Conversely, we found a statistically significant difference (p = 0.0014) in EAT scores in N + and N-. Hyperarousal and REM sleep instability in insomniac patients may create an unbalance of the neuroendocrine hypothalamic regulation leading to an appetite alteration.