The objective of this study is to examine the efficacy and safety of sertindole compared to risperidone when administered to treatment resistant schizophrenic patients. According to the dopamine hypothesis of schizophrenia, the antipsychotic effects of neuroleptic drugs are due to blockade of dopamine D2-receptors in the mesolimbic pathway. The blocking of dopamine receptors in the nigrostriatal pathway is thought to be responsible for the appearance of extrapyramidal adverse events. Most currently available antipsychotics block the action of dopamine receptors nonselectively in both pathways. Consequently, a high incidence of extrapyramidal adverse events is seen together with the antipsychotic activity of these drugs. Sertindole (Abbott-81968), combines a selective antagonist effect on mesolimbic dopamine neurons with seratonergic antagonist effects. The compound has no significant effect at relevant doses on nigostriatal dopamine neurons in in vivo animal experiments. Sertindole might be expected to improve symptoms of schizophrenia with minimal or no neurological adverse events. Subjects are studied for 16 weeks and followed for 1 year. The first 4 weeks they are treated with Haldol after which they are switched to Haloperidol for 4 weeks. They are then admitted to the hospital for 11 days and randomized to receive either sertindole or risperidone. Two weeks following discharge they are re-evaluated and followed every 3 months for 1 year.