Nootropics ( noh-?-TROP-iks), also known as smart drugs and cognitive enhancers, are drugs, supplements, and other substances that purport to improve cognitive function, particularly executive functions, memory, creativity, or motivation, in healthy individuals.
The use of cognition-enhancing drugs by healthy individuals in the absence of a medical indication is one of the most debated topics spanning numerous issues, including the ethics and fairness of their use, concerns over adverse effects, and the diversion of prescription drugs for nonmedical uses, among others. Nonetheless, the international sales of cognition-enhancing supplements exceeded US$1 billion in 2015 when global demand for these compounds grew.
The word nootropic was coined in 1972 by a Romanian psychologist and chemist, Corneliu E. Giurgea, from the Greek words ???? (nous), or "mind", and ??????? (trepein), meaning to bend or turn.
Video Nootropic
Availability and prevalence
In 2008, the most commonly used class of drug was stimulants, such as caffeine. Manufacturer's marketing claims for nootropic dietary supplements are usually not formally tested and verified by independent entities.
Use by students
The use of prescription stimulants is especially prevalent among students. Surveys suggest that 0.7-4.5% of German students have used cognitive enhancers in their lifetime. Stimulants such as dimethylamylamine and methylphenidate are used on college campuses and by younger groups. Based upon studies of self-reported illicit stimulant use, 5-35% of college students use diverted ADHD stimulants, which are primarily used for performance enhancement rather than as recreational drugs.
Several factors positively and negatively influence the use of drugs to increase cognitive performance. Among them are personal characteristics, drug characteristics, and characteristics of the social context.
Maps Nootropic
Side effects
The main concern with pharmaceutical drugs is adverse effects, and these concerns apply to cognitive-enhancing drugs as well. Long-term safety data are typically unavailable for nootropics. Racetams -- piracetam and other compounds that are structurally related to piracetam -- have few serious adverse effects and low toxicity, but there is little evidence that they enhance cognition in individuals who do not have cognitive impairments.
In the United States, dietary supplements may be marketed if the manufacturer can show that the supplement is generally recognized as safe, and if the manufacturer does not make any claims about the supplement's use to treat or prevent any disease or condition; supplements that contain drugs or for which treatment or prevention claims are made are illegal under US law.
Drugs
Central nervous system stimulants
In 2015, systematic medical reviews and meta-analyses of clinical research in humans indicated that certain central nervous system stimulants, only when used at low (therapeutic) concentrations, may enhance cognition in the general population.Relatively high doses of stimulants cause cognitive deficits.
- Amphetamine - systematic reviews and meta-analyses report that amphetamine benefits a range of cognitive functions (e.g., inhibitory control, episodic memory, working memory, and aspects of attention) in the general population, and these effects are especially notable in individuals with ADHD. A systematic review from 2014 noted that low doses of amphetamine may also improve memory consolidation, in turn leading to improved recall of information in non-ADHD youth.
- Methylphenidate - a Benzylpiperidine that may affect cognitive functions (e.g., working memory, episodic memory, and inhibitory control, aspects of attention, and planning latency) in the general population.
- Eugeroics (armodafinil and modafinil) - wakefulness promoting agents; modafinil increases alertness, particularly in sleep deprived individuals, and was noted to facilitate reasoning and problem solving in this group. Evidence for any benefit in those who are otherwise healthy is absent.
- Xanthines (most notably, caffeine) - shown to increase alertness, performance, and, in some studies, memory. Children and adults who consume low doses of caffeine showed increased alertness, yet a higher dose was needed to improve performance.
- Nicotine - A meta-analysis of 41 double-blind, placebo-controlled studies concluded that nicotine or smoking had significant positive effects on aspects of fine motor abilities, alerting and orienting attention, and episodic and working memory. A 2015 review noted that stimulation of the ?4?2 nicotinic receptor is responsible for certain improvements in attentional performance; among the nicotinic receptor subtypes, nicotine has the highest binding affinity at the ?4?2 receptor (ki=1 nM), which is also the biological target that mediates nicotine's addictive properties.
Racetams
Racetams, such as piracetam, oxiracetam, and aniracetam, are structurally similar compounds, which are often marketed as cognitive enhancers and sold over-the-counter. Racetams are often referred to as nootropics, but this property of the drug class is not confirmed. The racetams have poorly understood mechanisms of action.
According to the US Food and Drug Administration, "Piracetam is not a vitamin, mineral, amino acid, herb or other botanical, or dietary substance for use by man to supplement the diet by increasing the total dietary intake. Further, piracetam is not a concentrate, metabolite, constituent, extract or combination of any such dietary ingredient. [...] Accordingly, these products are drugs, under section 201(g)(1)(C) of the Act, 21 U.S.C. § 321(g)(1)(C), because they are not foods and they are intended to affect the structure or any function of the body. Moreover, these products are new drugs as defined by section 201(p) of the Act, 21 U.S.C. § 321(p), because they are not generally recognized as safe and effective for use under the conditions prescribed, recommended, or suggested in their labeling."
Miscellaneous
- L-Theanine - A 2014 systematic review and meta-analysis found that concurrent caffeine and L-theanine may promote alertness, attention, and task switching; these effects are most pronounced during the first hour post-dose. However, the European Food Safety Authority reports that when L-theanine is used by itself (i.e. without caffeine) there is insufficient information to determine if positive health effects exist.
- Tolcapone - a systematic review noted that it may improve verbal episodic memory and episodic memory encoding.
Dietary supplements
- Panax ginseng - A review by the Cochrane Collaboration concluded that "there is a lack of convincing evidence to show a cognitive enhancing effect of Panax ginseng in healthy participants and no high quality evidence about its efficacy in patients with dementia." According to the National Center for Complementary and Integrative Health, "[a]lthough Asian ginseng has been widely studied for a variety of uses, research results to date do not conclusively support health claims associated with the herb." According to a review published in the journal "Advances in Nutrition", multiple RCTs in healthy volunteers have indicated increases in accuracy of memory, speed in performing attention tasks and improvement in performing difficult mental arithmetic tasks, as well as reduction in fatigue and improvement in mood.
- Ginkgo biloba - An extract of Ginkgo biloba leaf (GBE) is marketed in dietary supplement form with claims it can enhance cognitive function in people without known cognitive problems. Studies have failed to find such effects on memory or attention in healthy people.
Null findings in systematic reviews
- Omega-3 fatty acids: DHA and EPA - two Cochrane Collaboration reviews on the use of supplemental omega-3 fatty acids for ADHD and learning disorders conclude that there is limited evidence of treatment benefits for either disorder. Two other systematic reviews noted no cognition-enhancing effects in the general population or middle-aged and older adults.
- Folate - no cognition-enhancing effects in middle-aged and older adults.
- Vitamin B6 - no cognition-enhancing effects in middle-aged and older adults.
- Vitamin B12 - no cognition-enhancing effects in middle-aged and older adults.
- Vitamin E - no cognition-enhancing effects in middle-aged and older adults.
- Pramipexole - no significant cognition-enhancing effects in healthy individuals.
- Guanfacine - no significant cognition-enhancing effects in healthy individuals.
- Clonidine - no significant cognition-enhancing effects in healthy individuals.
- Fexofenadine - no significant cognition-enhancing effects in healthy individuals.
- Salvia officinalis - Although some evidence is suggestive of cognition benefits, the study quality is so poor that no conclusions can be drawn from it.
See also
- Cognitive science
- Human enhancement
- List of drugs used by militaries
- Neurobiological effects of physical exercise § Cognitive control and memory
- Neuroenhancement
- Contentment
References
External links
- Media related to Nootropics at Wikimedia Commons
Source of article : Wikipedia
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