Amisulpride, a benzamide derivative, shows a unique therapeutic profile being atypical antipsychotic. At low doses, it enhances dopaminergic neurotransmission by preferentially blocking presynaptic dopamine D2/D3 autoreceptors. At higher doses, amisupride antagonises postsynaptic dopamine D2 and D3 receptors, preferentially in the limbic system rather than the striatum, thereby reducing dopaminergic transmission. In addition its antagonism at serotonin 5-HT7 receptors likely underlies the antidepressant actions. Amisulpride is approved for clinical use in treating schizophrenia in a number of European countries and also for treating dysthymia, a mild form of depression, in Italy.

Pimavanserin, marketed under the trade name Nuplazid, a non-dopaminergic atypical antipsychotic developed by Acadia Pharmaceuticals is the first and only medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. The mechanism of action of pimavanserin in the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis is unknown. However, the effect of pimavanserin could be mediated through a combination of inverse agonist and antagonist activity at serotonin 5-HT2A receptors and to a lesser extent at serotonin 5-HT2C receptors. In vitro, pimavanserin acts as an inverse agonist and antagonist at serotonin 5-HT2A receptors with high binding affinity (Ki value 0.087 nM) and at serotonin 5-HT2C receptors with lower binding affinity (Ki value 0.44 nM). Pimavanserin shows low binding to sigma 1 receptors (Ki value 120 nM) and has no appreciable affinity (Ki value >300 nM), to serotonin 5-HT2B, dopaminergic (including D2), muscarinic, histaminergic, or adrenergic receptors, or to calcium channels. Pimavanserin was approved by the FDA to treat hallucinations and delusions associated with psychosis experienced by some people with Parkinson's disease on April 29, 2016.

Brexpiprazole is a novel D2 dopamine and serotonin 1A partial agonist, called serotonin-dopamine activity modulator (SDAM), and a potent antagonist of serotonin 2A receptors, noradrenergic alpha 1B and 2C receptors. Brexpiprazole is approved for the treatment of schizophrenia, and as an adjunctive treatment for major depressive disorder (MDD). Although it failed Phase II clinical trials for ADHD, it has been designed to provide improved efficacy and tolerability (e.g., less akathisia, restlessness and/or insomnia) over established adjunctive treatments for major depressive disorder (MDD).Brexpiprazole is sold under the brand name Rexulti. Although the mechanism of action of brexpiprazole in the treatment of MDD and schizophrenia is unclear, the efficacy of brexpiprazole may be attributed to partial agonist activity at serotonin 1A and dopamine D2 receptors, and antagonist activity at serotonin 2A receptors.

Cariprazine is an antipsychotic approved by FDA for the treatment of schizophrenia and bipolar I disorder. The drug has a unique clinical action which is explained by its ability to act on dopamine D3 receptors. Pharmacology studies revealed that cariprazine is a dual partial agonist of dopamine D2 and D3 receptors as well as serotonin 5HT1a, 2a and 2b receptors.

Suvorexant is a selective dual antagonist of orexin receptors OX1R and OX2R. It has been approved for the treatment of insomnia. The mechanism by which suvorexant exerts its therapeutic effect in insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system is a central promoter of wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive.

Tasimelteon, developed by Vanda Pharmaceuticals Inc under license from Bristol-Myers Squibb Co, is a melatonin receptor agonist. Tasimelteon differs structurally from melatonin and drugs with known melatonin agonist activity, in particular by its distinct aromatic group and linker. Tasimelteon bears also no structural relationship to any other approved active substance. Tasimelteon is presumably acts through activation of MT1 and MT2 G-protein coupled receptors, which are involved primarily in inhibition of neuronal firing and phase shift of circadian rhythms. Tasimelteon is approved for the treatment of Non24-Hour Sleep-Wake Disorder.

Clobazam belongs to the 1,5-benzodiazepine class of drugs with antiepileptic properties. It has been used to treat anxiety and epilepsy since 1970s. In the US clobazam was approved for marketing in October of 2011 for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome. It is also approved for adjunctive therapy for epilepsy in patients who have not responded to first-line drugs and in children who are refractory to first-line drugs. The mechanism of action for clobazam is not fully understood but is thought to involve what is known as potentiation of GABAergic neurotransmission resulting from binding at a benzodiazepine site at the GABA(A) receptor. Possible side effects: constipation, fever, drowsiness, sedation, ataxia, aggressive behavior, lethargy, drooling, and irritability. Other side effects include: urinary tract infection, pneumonia, cough, dysphagia, dysarthria, bronchitis, insomnia, fatigue, decreased appetite, and increased appetite.

Lurasidone is a novel antipsychotic agent approved for the treatment of schizophrenia in a number of countries including the UK and is also approved in the USA and Canada for the treatment of bipolar depression as either a monotherapy or adjunctive therapy with lithium or valproate. In addition, lurasidone is in phase III of a clinical trial for the treatment patient with major depressive disorder and for the treatment of irritability associated with autistic disorder. The mechanism of action of lurasidone, as with other drugs having efficacy in schizophrenia, is unknown but is known, that lurasidone has a high affinity for dopamine D2, serotonin 5-HT2A and serotonin 5-HT7 receptors where it has antagonist effects. In addition, lurasidone is a partial agonist at the serotonin 5-HT1A receptor and has no appreciable affinity for histamine or muscarinic receptors.

Iloperidone, also known as Fanapt, Fanapta, and previously known as Zomaril, is an atypical antipsychotic for the treatment of schizophrenia. Iloperidone shows high affinity and maximal receptor occupancy for dopamine D2 receptors in the caudate nucleus and putamen of the brains of schizophrenic patients. The improvement in cognition is attributed to iloperidone's high affinity for α adrenergic receptors. Iloperidone also binds with high affinity to serotonin 5-HT2a and dopamine 3 receptors. Iloperidone binds with moderate affinity to dopamine D4, serotonin 5-HT6 and 5-HT7, and norepinephrine NEα1 receptors. Furthermore, iloperidone binds with weak affinity to serotonin 5-HT1A, dopamine D1, and histamine H1 receptors. Iloperidone is indicated for the treatment of acute schizophrenia.

Asenapine is an antipsychotic drug. The mechanism of action of asenapine, as with other drugs having efficacy in schizophrenia and bipolar disorder, is unknown. Asenapine exhibits high affinity for serotonin 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2B, 5-HT2C, 5-HT5, 5-HT6, and 5-HT7 receptors, dopamine D2, D3, D4, and D1 receptors, α1 and α2-adrenergic receptors, and histamine H1 receptors, and moderate affinity for H2 receptors. In in vitro assays asenapine acts as an antagonist at these receptors. It has been suggested that the efficacy of asenapine in schizophrenia is mediated through a combination of antagonist activity at D2 and 5-HT2A receptors. Asenapine is approved by the FDA for the acute treatment of schizophrenia in adults and for the acute treatment of manic or mixed episodes associated with bipolar I disorder, with or without psychotic features, in adults.