Most Axon Ligands™ in this category of compounds are labeled antipsychotic (typical, or atypical), since many of the common drugs to treat this class of mental disorders show affinity for both dopaminergic and serotonergic receptors (among several others). The first generation of antipsychotics (typical), developed in the 1950’s consisted of mainly phenothiazines (chlorpromazine), and butyrophenones (haloperidol). Though still considered benchmark antipsychotics, they are known for there unwanted side effects such as dry mouth, extra pyramidal side effects, and tardive dyskinesia. The atypical antipshychotics, or second generation antipsychotics, are less likely to cause the afore mentioned side effects, and improve the quality of live compared to the typical antipsychotics. However, this class of drugs is also far from free of side effects. Among them, many Clozapine (Axon 1146) analogues, Aripiprazole (Axon 1143), and Ziprazidone (Axon 1446).Based on a phylogenetic analysis, the family of serotonin (5-HT) receptors should be separated into two different classes among the subgroup of biogenic amine receptors of the rhodopsin-like family of GPCRs. The GPCR-A17 class includes all 5-HT2 and 5-HT6 receptors, while 5-HT1, 5-HT4 5HT-5 and 5HT7 receptors form an individual class: GPCR-A19.