Parental age and the risk of obsessive compulsive disorder and Tourette syndrome / chronic tic disorder in a nationwide population-based sample.

•Advancing paternal age is associated with several neuropsychiatric disorders.•There is limited understanding of this association with OCD and TS/CT.•Parental age as a risk factor seems to have opposing influences in various disorders.•This could be of importance when considering the etiological factors in these often comorbid disorders.