You're talking about cocaine or meth or something like it. There are side effects and controlling the dosage over time is difficult.

Mania comes at a cost (my friend's grandfather was manic depressive). Drugs also boost short term function at the cost of long term effects and a refractory period.

The experience of mania, from the DSM

Inflated self-esteem or grandiosity

Decreased need for sleep (e.g. feels rested after only 3 hrs sleep)

More talkative than usual, or pressure to keep talking

Flight of ideas or subjectively racing thoughts

Distractibilitv (i.e., attention too easily drawn to unimportant or irrelevant external stimuli), as reported or observed

Increase in goal directed activity (either socially, at work or school, or sexually) or psychomotor agitation (i.e., purposeless non-goal directed activity)

Excessive involvement in activities with high potential for painful consequences (e.g unrestrained buying sprees, sexual indiscretions. foolish business investments)

The experience of amphetamine from Wikipedia:

At therapeutic doses, amphetamine causes emotional and cognitive effects such as euphoria, change in desire for sex, increased wakefulness, and improved cognitive control. It induces physical effects such as improved reaction time, fatigue resistance, decreased appetite, elevated heart rate, and increased muscle strength. Larger doses of amphetamine may impair cognitive function and induce rapid muscle breakdown. Addiction is a serious risk with heavy recreational amphetamine use, but is unlikely to occur from long-term medical use at therapeutic doses. Very high doses can result in psychosis, which rarely occurs at therapeutic doses even during long-term use. Recreational doses are generally much larger than prescribed therapeutic doses and carry a far greater risk of serious side effects.^[sources 3]^

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Cognitive performance

In 2015, a systematic review and a meta-analysis of high quality clinical trials found that, when used at low (therapeutic) doses, amphetamine produces modest yet unambiguous improvements in cognition, including working memory, long-term episodic memory, inhibitory control, and some aspects of attention, in normal healthy adults;^[93][94]^ these cognition-enhancing effects of amphetamine are known to be partially mediated through the indirect activation of both dopamine D~1~ receptor and α~2~-adrenergic receptor in the prefrontal cortex.^[26][93]^ A systematic review from 2014 found that low doses of amphetamine also improve memory consolidation, in turn leading to improved recall of information.^[95]^ Therapeutic doses of amphetamine also enhance cortical network efficiency, an effect which mediates improvements in working memory in all individuals.^[26][96]^ Amphetamine and other ADHD stimulants also improve task saliency (motivation to perform a task) and increase arousal (wakefulness), in turn promoting goal-directed behavior.^[26][97][98]^ Stimulants such as amphetamine can improve performance on difficult and boring tasks and are used by some students as a study and test-taking aid.^[26][98][99]^ Based upon studies of self-reported illicit stimulant use, 5–35% of college students use diverted ADHD stimulants, which are primarily used for enhancement of academic performance rather than as recreational drugs.^[100][101][102]^ However, high amphetamine doses that are above the therapeutic range can interfere with working memory and other aspects of cognitive control.^[26][98]^

Even caffeine

Caffeine is a central nervous system stimulant that may reduce fatigue and drowsiness.^[11]^ At normal doses, caffeine has variable effects on learning and memory, but it generally improves reaction time, wakefulness, concentration, and motor coordination.^[59][60]^ The amount of caffeine needed to produce these effects varies from person to person, depending on body size and degree of tolerance.^[59]^ The desired effects arise approximately one hour after consumption, and the desired effects of a moderate dose usually subside after about three or four hours.^[7]^

Caffeine can delay or prevent sleep and improves task performance during sleep deprivation.^[61]^ Shift workers who use caffeine make fewer mistakes that could result from drowsiness.^[62]^

Caffeine in a dose dependent manner increases alertness in both fatigued and normal individuals.^[63]^

A systematic review and meta-analysis from 2014 found that concurrent caffeine and L-theanine use has synergistic psychoactive effects that promote alertness, attention, and task switching; these effects are most pronounced during the first hour post-dose.^[13]^

A 2025 systematic review and meta-analysis found that acute caffeine intake can improve reaction time and accuracy for cognitive tasks. Increased dosages can further improve reaction time but lead to decreases in accuracy after specific intake thresholds are reached.^[28]^

In habitual users, however, tolerance develops rapidly; the perceived attention and alertness boost after overnight abstinence primarily reverses mild withdrawal deficits (fatigue, reduced concentration) rather than elevating performance above a true non-dependent baseline, consistent with the withdrawal-reversal hypothesis.^[64][65]^