At D2 and possibly D3 receptors roxindole is a partial agonist with preferential actions at autoreceptors and has been touted as a 'selective' autoreceptor agonist, hence the justification of its application as an antipsychotic. Weaker activity at the serotonin 1B and 1D receptors has been seen. It is also a serotonin reuptake inhibitor (IC50 = 1.4 nM) and has been reported to act as a 5-HT2A receptorantagonist as well.