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.

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.

Paliperidone (9-OH-risperidone) is the primary active metabolite of the older antipsychotic risperidone. While its specific mechanism of action is unknown, it is believed that paliperidone and risperidone act via similar if not the same pathways. It has been proposed that the drug's therapeutic activity in schizophrenia is mediated through a combination of central dopamine Type 2 (D2) and serotonin Type 2 (5HT2A) receptor antagonism. Paliperidone is also active as an antagonist at alpha 1 and alpha 2 adrenergic receptors and H1 histaminergic receptors, which may explain some of the other effects of the drug. Paliperidone was approved by the FDA for treatment of schizophrenia on December 20, 2006. Very common adverse effects are: headache, tachycardia, somnolence and insomnia.

Ramelteon was approved by the United States (U.S.) in July 2005, and the Japanese Ministry of Health, Labour and Welfare in April 2010. It is currently available in the USA and Japan as ROZEREM and is indicated for the treatment of insomnia characterized by difficulty with sleep onset. In October 7, 2011, Takeda has decided to discontinue the development of ramelteon in Europe for the treatment of insomnia in order to best optimize Takeda’s resources for its research and development activities. Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT1 and MT2 receptors and selectivity over the MT3 receptor. Ramelteon demonstrates full agonist activity in vitro in cells expressing human MT1 or MT2 receptors, and high selectivity for human MT1 and MT2 receptors compared to the MT3 receptor. The activity of ramelteon at the MT1 and MT2 receptors is believed to contribute to its sleep-promoting properties since these receptors are acted upon by endogenous melatonin and are thought to be involved in the maintenance of the circadian rhythm underlying normal sleep-wake cycles. Ramelteon has no appreciable affinity for the GABA receptor complex or for receptors that bind neuropeptides, cytokines, serotonin, dopamine, noradrenaline, acetylcholine, and opiates.

Eszopiclone is a nonbenzodiazepine hypnotic, pyrrolopyrazine derivative of the cyclopyrrolone class and is indicated for the short-term treatment of insomnia. While Eszopiclone is a hypnotic agent with a chemical structure unrelated to benzodiazepines, barbiturates, or other drugs with known hypnotic properties, it interacts with the gamma-aminobutyric acid-benzodiazepine (GABABZ) receptor complex. Subunit modulation of the GABABZ receptor chloride channel macromolecular complex is hypothesized to be responsible for some of the pharmacological properties of benzodiazepines, which include sedative, anxiolytic, muscle relaxant, and anticonvulsive effects in animal models. Eszopiclone binds selectively to the brain alpha subunit of the GABA A omega-1 receptor. The mechanism of action of Eszopiclone is not completely understood. It is thought that Eszopiclone acts on the benzodiazepine receptors as an agonist and interacts with GABA-receptor complexes. Used for the treatment of insomnia.

Aripiprazole is the first next-generation atypical antipsychotic. The unique actions of aripiprazole in humans are likely a combination of "functionally selective" activation of D(2) (and possibly D(3))-dopamine receptors and serotonin 5-HT(1A) receptors, coupled with inhibition of 5-HT(2A) receptors. Aripiprazole was approved by FDA (Abilify trade name) for the treatment of schizophrenia; manic and mixed episodes associated with bipolar I disorder; major depressive disorder; irritability associated with autistic disorder; Tourette’s disorder and agitation associated with schizophrenia or bipolar mania.

Ziprasidone is atypical antipsychotic, approved by the U.S. Food and Drug Administration for the treatment of schizophrenia, and acute mania and mixed states associated with bipolar disorder. Intramuscilar injections of Ziprasidone are indicated for rapid control of the agitation in schizophrenic patients. Ziprasidone is used off-label for treatment of major depressive disorder, anxiety, obsessive compulsive disorder, borderline personality disorder. Ziprasidone functions as an antagonist at the D2, 5HT2A, and 5HT1D receptors, and as an agonist at the 5HT1A receptor.