Meta-analyses showed that psychotropic drugs (antidepressants, neuroleptics, benzodiazepines, antiepileptic drugs) and some cardiac drugs (digoxin, type IA anti-arrhythmics, diuretics) are associated with increased fall risk. Because balance and gait disorders are the most consistent predictors of future falls, falls due to use of these so-called fall-risk-increasing drugs (FRIDs) might be partly caused by impairments of postural control that these drugs can induce. Therefore, the effects of FRIDs on postural control were examined by reviewing literature. Electronic databases and reference lists of identified papers were searched until June 2013. Only controlled research papers examining the effects of FRIDs on postural control were included. FRIDs were defined according to meta-analyses as antidepressants, neuroleptics, benzodiazepines, antiepileptic drugs, digoxin, type IA anti-arrhythmics, and diuretics. Ninety-four papers were included, of which study methods for quantifying postural control, and the effects of FRIDs on postural control were abstracted. Postural control was assessed with a variety of instruments, mainly evaluating aspects of body sway during quiet standing. In general, postural control was impaired, indicated by an increase in parameters quantifying body sway, when using psychotropic FRIDs. The effects were more pronounced when people were of a higher age, used psychotropics at higher daily doses, with longer half-lives, and administered for a longer period. From the present literature review, it can be concluded that psychotropic drugs cause impairments in postural control, which is probably one of the mediating factors for the increased fall risk these FRIDs are associated with. The sedative effects of these drugs on postural control are reversible, as was proven in intervention studies where FRIDs were withdrawn. The findings of the present literature review highlight the importance of using psychotropic drugs in the older population only at the lowest effective dose and for a limited period of time.

We thank Dr. Toda [1] for his interesting question. Dr. Toda asked, in response to our literature review [2], whether psychotropic drugs with longer half-lives are more likely to increase fall risk than psychotropic drugs with shorter half-lives. In our paper [2], we concluded that psychotropic fall-risk-increasing drugs (FRIDs) cause impairments in postural control, which is probably one of the mediating factors for the increased fall risk with which these FRIDs are associated. The effects of psychotropic FRIDs on postural control are more pronounced when people are of higher age, use psychotropics at higher daily dosages, for a longer period of time, and when the half-life of the drug is longer. By the latter, we mean that the effects on postural control of benzodiazepines with intermediate to long half-lives ([8 h) sustain for a longer period of time after taking the drug (the so-called hangover effect).