“Category 1 included drugs associated with high prolactin levels, such as haloperidol, paliperidone and risperidone. Category 2 drugs, which had mid-range effects on prolactin, included the drugs iloperidone, lurasidone and olanzapine. Category 3 included drugs with less of an effect on prolactin levels, such as aripiprazole, asenapine, brexpiprazole, cariprazine, clozapine, quetiapine and ziprasidone.
The researchers compared the effects of all three categories of antipsychotic drugs to anticonvulsant drugs and lithium, which also often are prescribed to treat psychiatric disorders. When compared with those drugs, the relative risk of breast cancer was 62% higher for women who took Category 1 drugs and 54% higher for those taking Category 2 drugs, whereas Category 3 antipsychotics were not associated with any increase in breast cancer risk.”