Eltoprazine, a 5-HT1A/B receptor partial agonist, was created by Duphar in the 1980s (as DU-28853) and was subsequently developed by Solvay to treat pathological aggression. This drug is in clinical development for the treatment of Parkinson's disease levodopa-induced dyskinesia (PD-LID), Alzheimer's aggression and adult attention deficit hyperactivity disorder (adult ADHD). In addition, was shown, that the drug could be useful for normalizing prefrontal cognitive abilities, reducing aggression and impulsivity, and improving cognitive function in schizophrenia.

Kynurenic acid is a product of the normal metabolism of amino acid L-tryptophan which has been shown to have a neuroactive profile. It exhibits activity against NMDA receptors and Neuronal acetylcholine receptor subunit alpha-7. It has been investigated as a potential therapeutic compound and as a biomarker in a number of neurological disorders. Although Kenyruic acid exhibits a poor penetration of the blood-brain barrier, it remains to be of particular interest to those researching Schizophrenia.

Osanetant (SR-142801) is a NK3 receptor antagonist, it has a higher affinity for human and guinea pig NK3 receptors than for rat NK3 receptors. Osanetant was under development for the treatment of schizophrenia and other Central Nervous System (CNS) disorders. It was developed by Sanofi-Aventis (formerly Sanofi-Synthelabo). Sanofi was originally investigating its potential use as a treatment for psychosis and anxiety. Following phase IIa clinical trials, osanetant entered phase IIb development in February 2001. In a review of its R&D portfolio, the company announced in August 2005 that it would cease any further development of osanetant. This follows an earlier decision to discontinue development of eplivanserin for schizophrenia.

Meclinertant (SR-48692) is the first non-peptide antagonist of neurotensin receptors. It is potent and selective vs the high-affinity binding sites and with a small activity on the levocabastine-sensitive binding sites. It is active on several species including man without partial agonist properties. In vivo, it is active by oral route with a long duration of action and it is able to cross the blood-brain barrier. Meclinertant may be considered a powerful tool for investigating the role of neurotensin in physiological and pathological processes. Meclinertant has been developing for the treatment of anorexia nervosa; colorectal cancer; irritable bowel syndrome; pain; pancreatic cancer; prostate cancer; schizophrenia; small cell lung cancer however its development was discontinued.

Idalopirdine (Lu AE58054) is a Serotonin 6 receptor (5-HT6) antagonist. Idalopirdine exrets good oral bioavailability and robust efficacy in a rat model of cognitive impairment in schizophrenia. In rats idalopirdine potentiates the effects of acetylcholinesterase inhibitor donepezil on two pharmacodynamic biomarkers associated with cognition, i.e. neuronal oscillations and extracellular ACh levels in the hippocampus. Such potentiation could contribute to the procognitive effects of idalopirdine observed in donepezil-treated Alzheimer's disease patients. The compound is being developed by Lundbeck as an adjunctive therapy with acetylcholinesterase inhibitor donepezil, and is in phase III development for the treatment of Alzheimer's disease in multiple countries worldwide. A phase II trial for the treatment of cognitive impairment associated with schizophrenia was conducted; however no recent reports of development for idalopirdine have been identified.

N-(4-(2-Methoxyphenoxy)-phenyl-N-(2,2,2-trifluoroethylsulfonyl)-pyrid-3-ylmethylamine (LY487379) is a selective positive allosteric modulator at metabotropic glutamate subtype 2 receptors (mGluR2). The compound exerts antipsychotic and anxiolytic actions.

3-Methoxytyramine (3-MT) is a human trace amine that occurs as a metabolite of the neurotransmitter dopamine. It has been shown to act as an agonist of human TAAR1, and an inhibitor of mitochondrial respiration. 3-MT has garnered research interest for its potential links and implications to Parkinson's disease and other Neurological disorders.

PEAQX (NVP-AAM 077) is a potent and orally active NMDA antagonist with a 15-fold preference for human NMDA receptors with the 1A/2A(IC50=270 nM), rather than 1A/2B (29,600 nM). Animals treated with PCP or PEAQX on PN7, PN9, and PN11 showed a sensitized locomotor response to PCP challenge on PN28-PN35. PEAQX induced social suppression in rats.

SB-699551 is the first selective serotonin 5A receptor antagonist. SB-699551 showed an anxiolytic-like property in animal model. It demostrated efficacy against schizophrenia-like cognitive deficits and negative symptoms in rats. Blockade of 5-HT5A receptor with SB-699551 appear to be able to impair the consolidation of memory in rodents. In addition, 5-HT-induced spinal antinociception in the capsaicin and acetic acid tests was blocked by SB-699551.

CDPPB is a drug used in scientific research which acts as a positive allosteric modulator (PAM) selective for the metabotropic glutamate receptor subtype mGluR5 CDPPB was shown to be the first systemically available mGlu5 PAM, thus allowing for behavioral assessment in antipsychotic models, including reversal of amphetamine-induced hyperlocomotion and reversal of deficits in prepulse inhibition, both of which have translational validity in patients with schizophrenia eliciting positive symptoms and cognitive deficits in sensorimotor gating, respectively. CDPPB was shown to be efficacious in both of these models at moderate subcutaneous (s.c.) doses between 10 and 30 mg/kg. Numerous in vivo studies using CDPPB have recently surfaced which continue to add evidence and support for the potential to treat CNS disorders associated with aberrant NMDA receptor function, including the cognitive impairments and negative symptoms of schizophrenia.