Association of restless legs syndrome with nocturnal eating: a case-control study

We investigated the prevalence of nocturnal eating (sleep-related eating disorder-SRED or night-eating syndrome-NES) in patients with restless legs syndrome (RLS). One hundred RLS patients living in Emilia-Romagna (Northern Italy) and 100 matched controls randomly selected from the general population received two telephone interviews, and were investigated for socio-demographic characteristics, general health status, and presence of nocturnal eating. Additionally, subjects underwent interviews for psychopathological traits [by means of the Eating Disorder Inventory-2 (EDI-2), the Maudsley Obsessive-Compulsive Inventory (MOCI), the Beck Depression Inventory (BDI)], excessive daytime sleepiness (EDS), and subjective sleep quality. Compared with controls, RLS patients had more frequently pathological MOCI scores (24% versus 10%, P = 0.03), used significantly more drugs for concomitant diseases and had more nocturnal sleep impairment and EDS. SRED was more prevalent in RLS patients than controls (SRED: 33% versus 1%, P < 0.001). Medication use and pathological MOCI scores were more prevalent in RLS patients with SRED than among RLS patients without SRED. Use of dopaminergic or hypnotic drugs for RLS was not correlated with the presence of SRED. We demonstrate an association between RLS and SRED. Prospective studies are needed to establish the mechanisms underlying such association and whether it is causal.