Background: A retrospective, case-control chart review was performed to examine the relationship between the age of onset of idiopathic RBD and secondary associations.
Methods: Forty-eight idiopathic RBD patients were divided into early-onset and late-onset groups, compared to each other, and to their respective non-RBD controls.
Results: There were more females in the early-onset group as compared to their older counterparts (45% vs. 11%, p=0.007). Early-onset patients also had significantly more past and present psychiatric diagnoses [85% (both categories) vs. 46% and 36%, respectively, p<0.01 for both comparisons] and antidepressant use (80% vs. 46%, p=0.02) than the late-onset group. In comparison to non-RBD controls, early-onset patients again exhibited more psychiatric diagnoses (odds ratio=17.0 [3.5-83.4], equivalent for past and present diagnoses) and antidepressant use (odds ratio=12.0 [2.7-53.3]). Late-onset patients also had a higher frequency of past (odds ratio=7.2 [1.8-29.6]) and present (odds ratio=4.6 [1.1-19.3]) psychiatric diagnoses as compared to their non-RBD controls, but did not demonstrate a statistically significant difference in antidepressant use. There were otherwise no significant intergroup or intragroup differences with respect to the other assessed variables.
Conclusions: Although causality cannot be inferred, numerous implications can be entertained, particularly in the early-onset group, including direct or indirect correlations with medication use and/or psychopathology and the development of RBD. The relatively high number of females in the early-onset group suggests a unique clinical profile for a condition typically characterized as male-predominant.