Botond L. Buda¹, Gábor A. Tóth²

 

Sleep Related Movement Disorders from a Neuropsyciatric Perspective

 

¹Privte Practice for Neurologic Consultations, Szombathely, Hungary

²Berzsenyi Dániel College, Research Center for Anthropology,  Szombathely, Hungary

 

The prevalence of restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) is much higher than it has been estimated before. By severely fragmenting sleep, they inevitably trigger exhaustion, fatigue and excessive daytime sleepiness, thus seriously affecting occupational performance, social activities and the quality of life. Symptoms often overlap with those of depression, or, in children, with attention deficite hyperactivity disorder (ADHD), frequently leading to differential diagnostic failures. If left untreated for years, the development of matter-of-fact depression has to be taken into account. On the other hand, psychotropic medication quite often causes symptomatic sleep related movement disorders.

Between April 1, 2004 and March 31, 2005, 359 consecutive patients needing an antidepressant therapy were suggested to undergo a sleep related movement disorder (SRMD) screening prior to the beginning of the treatment.  In those 342 people who volunteered for the screening, anamnestic data suggesting the presence of a SRMD had been recorded at the beginning of the therapy, and four weeks later as well. International Restless Legs Syndrome Rating Scale and Epworth Sleepiness Scale scores were also recorded. Furthermore, patients underwent a forced immobilization test and a night actigraphy at the beginning and after a four weeks period.  21 patients, in whom at the very start definite sleep related movement disorder could be stated were excluded. Further 4 persons requiring a combined antidepressant therapy (two or more antidepressants) during the first four weeks already were dropped out, too. Data gained from the fourth-week screening protocol were evaluated.

SRMDs are quite often caused or aggravated by some antipsychotics, a wide range of antidepressants, antiepileptics, lithium, metoclopramide, cimetidine, and caffeine. However, it is a less known fact that even selective serotonin reuptake inhibitors and modern double action drugs (venlafaxine, mirtazapine, milnacipran) may also have the same adverse effects. Nofziger and his colleagues published their study in the Journal of Clinical Psychiatry in 2000, stating that bupropion (a double action dopaminergic and noradrenergic drug) did not cause sleep related movement disorders, but even affected the existing symptoms in a beneficial way. On examining our own patients, we arrived at a different conclusion: during the one-year screening period, the most serious SRMDs were recorded after bupropion administration. Two (11.2%) of our 17 bupropion patients developed serious SRMD. Following discontinuation of bupropion, symptoms have very soon completely disappeared.

The antidepressants used in the patients monitored in our survey reflects our specific antidepressant administering habits, thus, our results are suitable for drawing further conclusions only to a limited extent. All the same, the role of drugs where iatrogenic movement disorders were observed in a large percentage out of a smaller number of patients, or just in few persons out of a relatively larger number of treated patients worth further investigation. We can highlight bupropion, the beneficial effect of which as described by Nofzinger is not supported by our data. At the same time, in the case of the reversible inhibitor of monoaminooxidase moclobemide – despite of the large number of patients on this therapy – no sleep related movement disorder occurred in our patients.

Those suffering from a SRMD very often come first to see a psychiatrist. Authors insist that due care and attention should be given to proper differential diagnosis. On the other hand, in psychiatry patients also having SRMD, antidepressant should be chosen with caution, in collaboration with the neurologist.