We read with interest the recent study by Provini et al.,1 which showed an increased prevalence of sleep-related eating disorder (SRED) in patients with restless legs syndrome (RLS). The “out-of-control” nocturnal eating behaviors that they observed in RLS patients were strikingly similar to the compulsive and binge eating that we2 and others3 have observed in patients treated with dopamine agonists. In our experience, nocturnal eating is a common clinical feature of dopamine agonist-related compulsive eating in Parkinson's disease.2 Similar impulse control disorders (ICDs) have also been reported in patients treated with dopamine agonists for other conditions, including RLS.4–7

Although the authors reported no differences in dopaminergic medication usage in RLS patients with and without SRED, they showed a trend in this direction (67% versus 52%, P = 0.20) that might have reached statistical significance if they had discriminated between dopamine agonists and levodopa and/or included a quantitative comparison of dopamine agonist use in the two groups. The authors also reported higher Maudsley Obsessive-Compulsive Inventory scores in RLS subjects with SRED, suggesting that these patients may have had other comorbid compulsive tendencies; this is comparable to the frequent occurrence of other ICDs in patients with dopamine agonist-related compulsive eating.2, 8 The authors' observation of SRED in untreated RLS patients, however, raises the possibility of a biological link between RLS and SRED.

We recommend further study to evaluate the extent to which SRED in RLS patients is a side-effect of dopamine agonists versus a direct or indirect consequence of the disease. We congratulate the authors on bringing this important issue to attention.


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  • 1
    Provini F,Antelmi E,Vignatelli L, et al. Association of restless legs syndrome with nocturnal eating: a case-control study. Mov Disord 2009; 24: 871877.
  • 2
    Nirenberg MJ,Waters C. Compulsive eating and weight gain related to dopamine agonist use. Mov Disord 2006; 21: 524529.
  • 3
    Giladi N,Weitzman N,Schreiber S,Shabtai H,Peretz C. New onset heightened interest or drive for gambling, shopping, eating or sexual activity in patients with Parkinson's disease: the role of dopamine agonist treatment and age at motor symptoms onset. JPsychopharmacol 2007; 21: 501506.
  • 4
    Driver-Dunckley ED,Noble BN,Hentz JG, et al. Gambling and increased sexual desire with dopaminergic medications in restless legs syndrome. Clin Neuropharmacol 2007; 30: 249255.
  • 5
    Quickfall J,Suchowersky O. Pathological gambling associated with dopamine agonist use in restless legs syndrome. Parkinsonism Relat Disord 2007; 13: 535536.
  • 6
    Tippmann-Peikert M,Park JG,Boeve BF,Shepard JW,Silber MH. Pathologic gambling in patients with restless legs syndrome treated with dopaminergic agonists. Neurology 2007; 68: 301303.
  • 7
    Evans AH,Butzkueven H. Dopamine agonist-induced pathological gambling in restless legs syndrome due to multiple sclerosis. Mov Disord 2007; 22: 590591.
  • 8
    Dodd ML,Klos KJ,Bower JH,Geda YE,Josephs KA,Ahlskog JE. Pathological gambling caused by drugs used to treat Parkinson disease. Arch Neurol 2005; 62: 13771381.

Melissa J. Nirenberg MD, PhD*, Cheryl Waters MD†, * Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, New York, USA, † Department of Neurology, Columbia University Medical Centerr, New York, New York, USA.