In reference to the CYP2D6-biased ADRs, as hypothesized, SSRIs metabolized by CYP2D6 were significantly associated with cognitive processes and symptoms seen in altered mental status: nightmare, sleep disorder, paranoia, mood swings, withdrawal syndrome, hallucination, confusional state, suicidal ideation, and memory impairment, as shown in Table 1 and Fig. 3. Here, CYP2D6 is linked to substance withdrawal syndrome.