Nootropic

Nootropics (/noÊŠ.əˈtrÉ'pɨks/ noh-É™-TROP-iks), also referred to as smart drugs, memory enhancers, neuro enhancers, cognitive enhancers, and intelligence enhancers, are drugs, supplements, nutraceuticals, and functional foods that improve one or more aspects of mental function, such as working memory, motivation, and attention. The word nootropic was coined in 1972 by the Romanian Dr. Corneliu E. Giurgea, derived from the Greek words νους nous, or "mind", and τρέπειν trepein meaning to bend or turn.

Availability and prevalence

At present, there are only a few drugs which have been shown to improve some aspect of cognition in medical reviews. Many more are in different stages of development. The most commonly used class of drug is stimulants, such as caffeine.

These drugs are purportedly used primarily to treat cognitive or motor function difficulties attributable to such disorders as Alzheimer's disease, Parkinson's disease, Huntington's disease and ADHD. However, more widespread use is being reported by some researchers, despite concern for further research. Nevertheless, intense marketing may not correlate with efficacy; while scientific studies support the beneficial effects of some compounds, the marketing claims by manufacturers of dietary supplements are usually not formally tested by independent entities.

Academic use

In academia, modafinil has been used to increase productivity, although its long-term effects have not been assessed in healthy individuals. Stimulants such as dimethylamylamine and methylphenidate are used on college campuses and by younger groups. One survey found that 7% of students had used stimulants for a cognitive edge, and on some campuses use in the past year is as high as 25%. The use of prescription stimulants is especially prevalent among students attending academically competitive colleges.

Surveys suggest that 3â€"11% of American students and 0.7â€"4.5% of German students have used cognitive enhancers in their lifetime.

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.

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 is typically unavailable for some types of nootropics (e.g., many non-pharmaceutical cognitive enhancers, newly developed pharmaceuticals and pharmaceuticals with short-term therapeutic use). While certain racetam compounds are suspected to have nootropic qualities, few side-effects, and a wide therapeutic window (low overdose risk), other cognitive enhancers may be associated with a high incidence of adverse effects or a narrower therapeutic window (higher overdose risk). While addiction to stimulants is sometimes asserted to be a cause for concern, a very large body of research on the therapeutic use of the "more addictive" psychostimulants indicate that addiction is fairly rare in therapeutic doses.

In the United States, unapproved drugs or dietary supplements do not require efficacy approval before being sold.

Drugs

Stimulants

Certain stimulants will enhance cognition in the general population (e.g., direct or indirect mesocortical DRD1 agonists as a class), but only when used at low (therapeutic) concentrations. Relatively high doses of stimulants will result in cognitive deficits.

• Amphetamine pharmaceuticals (Adderall, dextroamphetamine, and lisdexamfetamine [a prodrug]) â€" TAAR1 agonists that mimic the effect of endogenous phenethylamine. Benefits in cognitive control and working memory are evident in the general population, and especially in individuals with ADHD. A 2015 meta-analysis of high quality evidence found that therapeutic doses of amphetamine and methylphenidate improve performance on working memory, episodic memory, and inhibitory control tests in normal healthy adults. It also improves task saliency (motivation to perform a task) and performance on tedious tasks that require a high degree of effort.
• Methylphenidate â€" a substituted phenethylamine that improves cognitive control (e.g., working memory, episodic memory, and inhibitory control) in the general population. It also improves performance on tedious tasks that require a high degree of effort. At above optimal doses, methylphenidate has offtarget effects that can decrease learning by activating neurons not involved in the task at hand.
• Eugeroics (armodafinil and modafinil) â€" wakefulness promoting agents; increase alertness, particularly in sleep deprived individuals. They are clinically prescribed for narcolepsy, shift work sleep disorder, and daytime sleepiness remaining after sleep apnea treatments.
• Xanthines â€" most notably, caffeine â€" 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 â€" 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.

Miscellaneous

• Phosphatidylserine (a phospholipid) with DHA and EPA (omega-3 fatty acids) â€" a review of literature and subsequent randomized controlled trial indicate concurrent supplemental use can protect and potentially improve brain function, with clinical benefits for those with ADHD and other disorders. Two Cochrane Collaboration reviews on the use of supplemental omega-3 fatty acids alone (without phosphatidylserine) for ADHD and learning disorders conclude that there is limited evidence of treatment benefits for either disorder.
• Tianeptine â€" enhances several metrics of cognition in animal models. It has also been shown to prevent stress-induced dendritic remodeling in various brain structures, and antagonizes alcohol's neurodegenerative effects.
• Valproate â€" a study has suggested that valproate may be able to enhance the cognitive ability of absolute pitch.

Nutraceuticals

• Bacopa monnieri â€" A nutraceutical herb with "neural tonic" and memory enhancing properties shown in humans in a double-blinded RCTs.
• Panax ginseng â€" 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 â€"  Different reviews come to different conclusions. A 2009 Cochrane review found not enough evidence to make conclusions in those with dementia. Another review stated "there is consistent evidence that chronic administration improves selective attention, some executive processes and long-term memory for verbal and non-verbal material."
• Isoflavones â€" A double-blind, placebo-controlled study showed improvement in spatial working memory after administration of isoflavones. One RCT showed soy isoflavone supplementation improved performance on 6 of 11 cognitive tests, including visual-spatial memory and construction, verbal fluency and speeded dexterity, but worse on two tests of executive function.

Racetams

The racetams are structurally similar compounds, such as pramiracetam, oxiracetam, coluracetam, and aniracetam, 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 well established. The racetams have poorly understood mechanisms of action; however, piracetam and aniracetam are known to act as positive allosteric modulators of AMPA receptors and appear to modulate cholinergic systems.

See also

• Cognitive science
• Human enhancement
• Intelligence amplification
• Life extension
• Memory and aging
• Neurobiological effects of physical exercise
• Psychoanaleptic

References

External links

• Greely, Henry; Sahakian, Barbara; Harris, John; Kessler, Ronald C.; Gazzaniga, Michael; Campbell, Philip; Farah, Martha J. (December 10, 2008). "Towards responsible use of cognitive-enhancing drugs by the healthy". Nature (Nature Publishing Group) 456 (7223): 702â€"5. Bibcode:2008Natur.456..702G. doi:10.1038/456702a. ISSN 1476-4687. OCLC 01586310. PMID 19060880. Retrieved March 25, 2014. (subscription required (help)).