Fenmetozole is an alpha-2 adrenergic receptor antagonist which was developed for the treatment of schizophrenic and/or depressed patients, however never reached the market. It was also shown that the drug may reduce symptoms of minimal brain dysfunction in children and antagonize the effect of barbiturates and ethanol.

Nisoxetine, 3-(o-methoxyphenoxy)-3-phenyl-N-methyl-propyl-amine, is a most active and selective inhibitor of norepinephrine uptake, which was developed by Eli Lilly as an antidepressant drug. It was shown that nisoxetine dose-dependently reduced acute food intake and the additive effect of it was preserved in obese mice. In addition, was revealed that nisoxetine produced local but not systemic analgesia against cutaneous nociceptive stimuli in rodents. However, this drug has no clinical applications in humans.

Setoperone is and antagonist of the brain serotonin 5-HT2 receptor and particular the 5-HT2A isoform. Setoperone is radiolabeled with the radioisotope fluorine-18 and is used in positron emission tomography (PET) in neuroimaging for the study neuropsychiatric disorders, such as schizophrenia and depression.

Vanoxerine, also known as GBR-12909, is a piperazine derivative exhibiting potent selective inhibition of sodium-dependent dopamine reuptake transporters. Vanoxerine has been in clinical trials for Parkinsonism, depression and cocaine addiction but lacked efficacy. Vanoxerine has also been observed as a potent blocker of the following channels: cardiac hERG/IKr potassium channel, Calcium channel, voltage-dependent, L type, alpha 1C subunit (also known as Cav1.2) and voltage-gated sodium channel Nav 1.5. Vanoxerine was studied as a potential treatment for atrial fibrillation. However, phase III clinical trials for this condition were terminated because of cardiac safety concerns. Research also indicates that vanoxerine may have additional mechanisms of action including antagonist action at nicotinic acetylcholine receptors (nAChRs).

S-(+)-niguldipine is a more active enantiomer and is a selective antagonist for the and α1A-adrenoceptor. In addition, it can be used for discriminating of alpha 1A- from alpha 1B-adrenoceptors. There were made attempts to investigate the antidepressant action of S-(+)-niguldipine on rats, but that studies were unsuccessful.

Trocimine (N-3,4,5-trimethoxybenzoylheptamethylenimine) is heptamethylenimine derivative with antidepressant activity.

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.

Hepzidine (BS 7051) is a compound, possessing antidepressive and anticholinergic properties.

Phenylacetate is the ester of a phenol and acetic acid. It is a metabolite of anticancer drug phenylbutyrate (PB), natural neurotransmitter phenylethylamine. Naturally, it is an odorant found in strawberries, passion fruit, and black tea. Phenylacetate level in urine was used as a marker for the diagnosis of some forms of unipolar major depressive disorders. Phenylacetate is used as a tool substrate to study esterase activity in the blood of patients in clinical studies of the effect of nutritional supplements on paraoxonase-1 levels.

Clorgiline is a monoamine oxidase (MAO) inhibitor. Specifically, it is an irreversible and selective inhibitor of MAO-A. Clorgiline was under investigation for antidepressant and anxiolytic potential but has never been marketed, likely due to efficacy concerns. It continues to see routine use as a molecular probe in biomedical research examining a number of neurological disease and cancer models. In addition to inhibiting the MAO-A receptor, it has also been found to bind to the sigma1 receptor, and with high affinity to the I2 imidazoline receptor.