Dopaminergic, serotonergic, and adrenergic receptors are targets for therapeutic actions in schizophrenia. Dopamine D 2 receptor partial agonists such as aripiprazole represent a treatment option for patients with this severe disorder. The ineffectiveness of terguride, another D 2 receptor partial agonist, in treating schizophrenia was recently attributed to its considerably high intrinsic activity at D 2 receptors. In this study, we used functional assays for recombinant D 2 receptors and native 5-hydroxytryptamine 2A (5-HT 2A ), a 2C -adrenergic, and histamine H 1 receptors to compare the pharmacological properties of terguride and three of its halogenated derivatives (2-chloro-, 2-bromo-, 2-iodoterguride) with those of aripiprazole. Subsequently, we studied the antidopaminergic effects of 2-bromoterguride using amphetamine-induced locomotion (AIL (hD 2S ) receptors that were half as high as the intrinsic activity for terguride; aripiprazole lacked agonist activity. 2-Bromoterguride and aripiprazole activated D 2S receptor-mediated inhibition of cAMP accumulation to the same extent; intrinsic activity was half as high as that of terguride. All compounds tested behaved as antagonists at human D 2long /Ga o (hD 2L /Ga o ) receptors. Compared with aripiprazole, terguride and its derivatives displayed higher affinity at porcine 5-HT 2A receptors and a 2C -adrenoceptors and lower affinity at H 1 receptors. 2-Bromoterguride inhibited AIL and did not induce catalepsy in rats. Because of its in vitro and in vivo properties, 2-bromoterguride may be a strong candidate for the treatment of schizophrenia with a lower risk to induce EPS.