CYP2D6 and psychotic disorder: Figure 6 shows the 10 most prevalent specific transitions by weight. Of these, only the olanzapine to quetiapine transition did not involve a ‘CYP2D6-PGx antipsychotic’. When recorded, data about the reason(s) for ‘antipsychotic-to-antipsychotic’ transitions were extracted. Contributing factors varied by specific psychosis drug. Of the 246 transitions, the most common documented reason was ADRs/tolerability 103 (41.9%), followed by a lack of therapeutic response 64 (26%). Figure 7 shows the documented reasons for transitions.