Determination of antidepressants and benzodiazepines in paired hair and nail samples

•A LC-MS/MS method for psychoactive medicines in nails and hair was developed.•Hair concentrations were higher than nail concentrations except for diazepam.•Concentrations in fingernails were lower than in toenails in most cases.•Diazepam and nordiazepam showed different pattern between hair and nails.•No effect of antifungal treatment on nail concentrations was observed.