Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class and is the most commonly consumed psychoactive substance globally. It is mainly used for its eugeroic, ergogenic, or nootropic (cognitive-enhancing) properties. Caffeine acts by blocking binding of adenosine at a number of adenosine receptor types, inhibiting the centrally depressant effects of adenosine and enhancing the release of acetylcholine. Caffeine has a three-dimensional structure similar to that of adenosine, which allows it to bind and block its receptors. Caffeine also increases cyclic AMP levels through nonselective inhibition of phosphodiesterase, increases calcium release from intracellular stores, and antagonizes GABA receptors, although these mechanisms typically occur at concentrations beyond usual human consumption.
Phencyclidine or phenylcyclohexyl piperidine (PCP), also known in its use as a street drug as angel dust among other names, is a dissociative anesthetic mainly used recreationally for its significant mind-altering effects. PCP may cause hallucinations, distorted perceptions of sounds, and violent behavior. As a recreational drug, it is typically smoked, but may be taken by mouth, snorted, or injected. It may also be mixed with cannabis or tobacco.
Caffeine dependence is a condition characterized by a set of criteria, including tolerance, withdrawal symptoms, persistent desire or unsuccessful efforts to control use, and continued use despite knowledge of adverse consequences attributed to caffeine. It can appear in physical dependence or psychological dependence, or both. Caffeine is one of the most common additives in many consumer products, including pills and beverages such as caffeinated alcoholic beverages, energy drinks, pain reliever medications, and colas. Caffeine is found naturally in various plants such as coffee and tea. Studies have found that 89 percent of adults in the U.S. consume on average 200 mg of caffeine daily. One area of concern that has been presented is the relationship between pregnancy and caffeine consumption. Repeated caffeine doses of 100 mg appeared to result in smaller size at birth in newborns. When looking at birth weight however, caffeine consumption did not appear to make an impact.
Fencamfamin (INN), also known as fencamfamine or by the brand names Glucoenergan and Reactivan, is a stimulant which was developed by Merck in the 1960s.
Naphthylaminopropane, also known as naphthylisopropylamine (NIPA), is an experimental drug that was under investigation for the treatment of alcohol and stimulant addiction.
MMDA-2 (2-methoxy-4,5-methylenedioxyamphetamine) is a psychedelic drug of the amphetamine class. It is closely related to MMDA and MDA.
5-Fluoro-α-methyltryptamine, also known as PAL-212 or PAL-544, is a putative stimulant, entactogen, and psychedelic tryptamine derivative related to α-methyltryptamine (αMT).
Quipazine, also known as 1-(2-quinolinyl)piperazine, is a serotonergic drug of the arylpiperazine family and an analogue of 1-(2-pyridinyl)piperazine which is used in scientific research. It was first described in the 1960s and was originally intended as an antidepressant but was never developed or marketed for medical use.
MDAI, also known as 5,6-methylenedioxy-2-aminoindane, is an entactogen drug of the 2-aminoindane group which is related to MDMA and produces similar subjective effects.
5-Iodo-2-aminoindane (5-IAI) is an entactogen drug of the 2-aminoindane group. Human anecdotal reports suggest that it is entactogenic but produces little euphoria or stimulation.
Benocyclidine, also known as benzothiophenylcyclohexylpiperidine (BTCP), is a psychoactive recreational drug of the arylcyclohexylamine class which is related to phencyclidine (PCP). It was first described in a patent application naming Marc Caron and colleagues at Duke University in 1997.
Jane Stewart is a Canadian neuroscientist who has been active in the fields of psychology, psychiatry, and psychopharmacology. She is a professor emerita at Concordia University in Montreal, Canada.
Arylcyclohexylamines, also known as arylcyclohexamines or arylcyclohexanamines, are a chemical class of pharmaceutical, designer, and experimental drugs.
meta-Methoxyamphetamine (MMA), also known as 3-methoxyamphetamine (3-MA), is a stimulant drug from the amphetamine family.
Melanocyte-inhibiting factor (also known as Pro-Leu-Gly-NH2, Melanostatin, MSH release–inhibiting hormone or MIF-1) is an endogenous peptide fragment derived from cleavage of the hormone oxytocin, but having generally different actions in the body. MIF-1 produces multiple effects, both blocking the effects of opioid receptor activation, while at the same time acting as a positive allosteric modulator of the D2 and D4 dopamine receptor subtypes, as well as inhibiting release of other neuropeptides such as alpha-MSH, and potentiating melatonin activity.
Levofenfluramine (INN), or (−)-3-trifluoromethyl-N-ethylamphetamine, also known as (−)-fenfluramine or (R)-fenfluramine, is a drug of the amphetamine family that, itself (i.e., in enantiopure form), was never marketed. It is the levorotatory enantiomer of fenfluramine, the racemic form of the compound, whereas the dextrorotatory enantiomer is dexfenfluramine. Both fenfluramine and dexfenfluramine are anorectic agents that have been used clinically in the treatment of obesity (and hence, levofenfluramine has been as well since it is a component of fenfluramine). However, they have since been discontinued due to reports of causing cardiovascular conditions such as valvular heart disease and pulmonary hypertension, adverse effects that are likely to be caused by excessive stimulation of 5-HT2B receptors expressed on heart valves.
Theacrine, also known as 1,3,7,9-tetramethyluric acid, is a purine alkaloid found in Cupuaçu and in a Chinese tea known as kucha. It shows anti-inflammatory and analgesic effects and appears to affect adenosine signalling in a manner similar to caffeine. In kucha leaves, theacrine is synthesized from caffeine in what is thought to be a three-step pathway. Theacrine and caffeine are structurally similar.
Caffeine-induced anxiety disorder is a subclass of the DSM-5 diagnosis of substance/medication-induced anxiety disorder.
Sheena Josselyn is a Canadian neuroscientist and a full professor of psychology and physiology at Hospital for Sick Children and The University of Toronto. Josselyn studies the neural basis of memory, specifically how the brain forms and stores memories in rodent models. She has made critical contributions to the field of Neuronal Memory Allocation and the study of engrams.
Bromerguride, also known as 2-bromolisuride, is an antidopaminergic and serotonergic agent of the ergoline group which was described as having atypical antipsychotic properties but was never marketed. It was the first antidopaminergic ergoline derivative to be discovered. The pharmacodynamic actions of bromerguride are said to be "reversed" relative to its parent compound lisuride, a dopaminergic agent.
