A young female with organic delusional syndrome induced by hyperprolactinemia was admitted to the Psychiatry Clinic of Ankara Social Security Hospital. The most striking characteristic of her history was either worsening of the endocrinologic clinical outcome under conventional neuroleptic treatment or worsening of clinical psychiatric outcome under bromocriptine therapy. A new atypical neuroleptic, melperone, suggested to minimally affect plasma prolactin levels, was started. Her psychotic complaints significantly subsided and she was devoid of any symptomatological change regarding her endocrinological status. These results were discussed.