Neuroleptic drugs elevate prolactin levels; the elevation persists during chronic administration. Tissue culture experiments indicate that approximately one-third of human breast cancers are prolactin dependent in vitro , a factor of potential importance if the prescription of these drugs is contemplated in a patient with a previously detected breast cancer . Although disturbances such as galactorrhea , amenorrhea , gynecomastia , and impotence have been reported, the clinical significance of elevated serum prolactin levels is unknown for most patients. An increase in mammary neoplasms has been found in rodents after chronic administration of neuroleptic drugs. Neither clinical studies nor epidemiologic studies conducted to date, however, have shown an association between chronic administration of these drugs and mammary tumorigenesis; the available evidence is considered too limited to be conclusive at this time.
Nonadherence to medications is a significant problem; in a recent study, 74 percent of patients discontinued their medication within 18 months. 16 Nonadherence often leads to relapse of symptoms. Atypical antipsychotics were initially thought to help with adherence because of their lower rate of neurologic side effects. However, meta-analyses have found that drop-out rates and relapse prevention are no better with atypical antipsychotics than with neuroleptics. 17 , 18 Meta-analyses also have found that in terms of symptom scores and drop-out rates, atypical antipsychotics are better than high dosages (., more than 12 mg per day) of haloperidol (Haldol); there was no advantage when the dosage of haloperidol was less than 12 mg per day. 17 In other words, many of the perceived benefits of atypical antipsychotics actually were a result of the excessive doses of first-generation antipsychotics that were used for comparison in randomized trials. 17 Evidence suggests that delays in initiating therapy with antipsychotics may result in a lifetime deleterious effect on psychotic episodes and social adjustment. 19 , 20 If initiation of antipsychotic therapy is delayed because of limited psychiatric resources, family physicians should consider starting medications instead.