Restless legs syndrome and primary headaches: a clinical study.

Based on recent data about the association between restless legs syndrome (RLS) and migraine, we performed an observational study on the occurrence of RLS in patients affected by primary headaches. Two hundred headache patients (149 women and 51 men) and 120 (90 women and 30 men) sex-and age-matched control subjects were included. In the headache group, migraine without aura (MO) was the most represented headache type (n=114), followed by the "mixed" group (n=40) with MO, migraine with aura (MA) and frequent episodic tension-type headache (ETTH) in various combinations, and by ETTH alone (n=22). The remaining patients suffered from MA alone (n=10 MA), episodic cluster headache (ECH n=12) and primary stabbing headache (n=2). RLS frequency was significantly higher in headache patients than in control subjects (22.4% vs. 8.3, p=0.002) independently of sex, although with a female preponderance (84%) in both groups. More than 60% (n=27) of RLS patients were affected by MO and 30% (n=13) by a combination of two headache types (p> or =0.001), with a very low frequency of RLS for the other types of headache. No RLS patient had ECH. No statistical differences were observed among clinical characteristics of different types of headache in groups with and without RLS. In both headache and control groups, higher scores for depression and anxiety were more frequent in subjects with RLS compared with those without RLS. Furthermore, headache patients with RLS reported sleep disturbances more frequently compared to those without RLS (50.0% vs. 32.7%; p<0.0001) and showed a normal or underweight body mass index. Our data seem to confirm the existence of an association between RLS and primary headaches, particularly with migraine, as already demonstrated. The absence of RLS in ECH patients is very interesting. Many pathogenetic considerations about links between RLS and primary headaches could be given, the most fitting involving dopamine and melatonin.