Nootropic

Nootropics, popularly referred to as "smart drugs", "smart nutrients", "cognitive enhancers" and "brain enhancers", are a class of drugs that improve impaired human cognitive abilities (the functions and capacities of the brain).[1] The term covers a broad range of substances including drugs, nutrients and herbs that have purported cognitive enhancing effects.

The word nootropic was coined in 1964 by the Romanian Dr. Corneliu E. Giurgea, derived from the Greek words noos, or "mind," and tropein meaning "to bend/turn". Typically, nootropics are alleged to work by altering the availability of the brain's supply of neurochemicals (neurotransmitters, enzymes, and hormones), by improving the brain's oxygen supply, or by stimulating nerve growth. However the efficacy of alleged nootropic substances in most cases has not been conclusively determined. This is complicated by the difficulty of defining and quantifying cognition and intelligence.

Contents

Availability

The drugs are used to treat people with cognitive learning difficulties, neural degradation (Alzheimer's disease or Parkinson's disease), and for cases of oxygen deficit to prevent hypoxia. These drugs have a variety of human enhancement applications as well and are marketed heavily on the World Wide Web. Nevertheless, intense marketing may not correlate with efficacy; while scientific studies support some of the claimed benefits, it is worth noting that many of the claims attributed to most nootropics have not been formally tested.

Therapy or enhancement

Some argue that nootropics may theoretically be used for human enhancement, boosting mental function in otherwise normal healthy people. However, there is much controversy over the legitimacy (efficacy) and ethics of such applications. This may contribute to the lack of research on such effects.

Examples

The term "drug" here is used as a legal designation, and does not indicate greater efficacy. With nootropics, the effects, effectiveness, and potency differ from substance to substance and from individual to individual. See the substance descriptions below for more detail.

Replenishing and increasing neurotransmitters

As the brain ages, its ability to produce and maintain youthful levels of neurotransmitters declines.[2] There are various reasons for such an insufficiency. For instance, there might be a lack of enzymes involved in the neurotransmitter synthesis. Nevertheless, in many cases, providing the brain with ample raw materials necessary to make neurotransmitters can restore them to more youthful levels and thus help maintain cognitive function at vigorous youthful levels. Furthermore, there are declines in immune and endocrine functioning.[3] Certain nootropics enhance immune and endocrine functioning.

Cholinergics

Cholinergics are substances that affect the neurotransmitter acetylcholine or the components of the nervous system that use acetylcholine. Acetylcholine facilitates memory, concentration, focus, and high-order thought processes (abstract thought, calculation, innovation, etc.). Increasing the availability of this neurotransmitter in the brain may improve these functions and increase the duration in which they may be engaged without slowing down or stopping. Oversupplying the brain with acetylcholine may have the opposite effect, temporarily reducing rather than improving mental performance. Cholinergic nootropics include acetylcholine precursors and cofactors, and acetylcholinesterase inhibitors:

Piracetam
Main article: Piracetam

Piracetam (Nootropil) is the original[4] and most commonly taken[5][4] nootropic supplement. It is a cholinergic agent synergistic with DMAE, Centrophenoxine, choline, Alpha-GPC and Hydergine. It increases brain cell metabolism and energy levels,[6][4] and speeds up interhemispheric flow of information (left-right brain hemisphere communication). It increases alertness,[7] improves concentration, and enhances memory. Protects neurons from hypoxia,[4] and stimulates growth of acetylcholine receptors. It may also cause nerves to regenerate. Piracetam markedly decreases the formation of neuronal lipofuscin.[8] It improves posture in elderly people.[9] It is not regulated in the US. It is a pyrrolidone derivative.

Aniracetam
Main article: Aniracetam

Aniracetam is a pyrrolidone derivative drug, analogous of piracetam, and considered more potent. Like piracetam, aniracetam protects against some memory impairing chemicals, such as diethyldithiocarbamate and clonidine.[10] Also like piracetam, aniracetam may enhance memory in aging adults by increasing levels of brain biogenic monoamines, which are beneficial to learning and memory.[2] Both racetams have possible therapeutic use in treating fetal alcohol syndrome.[11] Aniracetam increases vigilance.[7] Aniracetam has shown to positively potentiate AMPA receptors.

Other cholinergics

Excess acetylcholine is considered by many to be potentially harmful; see acetylcholinesterase inhibitor.

Acetylcholinesterase inhibitors

Acetylcholinesterase inhibitors function by inhibiting the cholinesterase enzyme which breaks down the neurotransmitter acetylcholine. They exist in the form of poisons and have been used as weapons, but they are also used to treat Alzheimer's patients. Donepezil, galantamine, and Huperzine A are notable among these.

Dopaminergics

Dopaminergics are substances that affect the neurotransmitter dopamine or the components of the nervous system that use dopamine. Dopamine is produced in the synthesis of all catecholamine neurotransmitters, and is the rate limiting step for this synthesis. Dopaminergic nootropics include dopamine precursors and cofactors (vitamin C and vitamin B6), and dopamine reuptake inhibitors:

Serotonergics

Serotonergics are substances that affect the neurotransmitter serotonin or the components of the nervous system that use serotonin. Serotonergic nootropics include serotonin precursors and cofactors, and serotonin reuptake inhibitors:

Anti-depression, adaptogenic (antistress), and mood stabilization

Stress, depression, and depressed mood negatively affect cognitive performance. It is reasoned that counteracting and preventing depression and stress may be an effective nootropic strategy.

Below are a list of substances purported to function as nootropics, and claimed effects:

Brain function and improved oxygen supply

Mental agility, concentration, stamina, and focus

Purported memory enhancement and learning improvement

All of the "nergics" listed above are purported to improve memory (encoding and recall), as do all nootropics which improve general brain performance in categories such as the brain energy and oxygen supply, and nerve growth stimulation and protection. Other agents purported to have these specific benefits are mentioned in their own sections.

Other nootropics with specific effects on memory encoding and recall include:

Nerve growth stimulation and brain cell protection

Recreational drugs with purported nootropic effects

See also: Controlled substances act and Misuse of Drugs Act 1971

Dietary nootropics

Some regular food items are rich sources of substances with alleged nootropic benefits:

Other nootropics

Contentious or possibly unsafe nootropics

See also

Brain and neurology

Thought and thinking (what nootropics are used for)

Health

References

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