In this study, patients treated with fluoxetine, fluvoxamine, and paroxetine—all CYP2D6 substrates—had a 337% increase in odds of nightmares and a 119% increased odds of sleep disorder and thus rejects the null hypothesis and affirms the association of the CYP2D6 SSRI substrates with of de-realization of thought processes. Here, CYP2D6 is linked to sleep disorder.