Attention-deficit hyperactivity disorder (ADHD) stimulant medications as cognitive enhancers

Abstract

Recent increases in attention deficit hyperactivity disorder (ADHD) diagnoses, and the escalation of stimulant prescriptions, has raised concern about diversion and abuse of stimulants, as well as the ethics of using these drugs as “cognitive enhancers.”Such concern appears misplaced in the face of substantial evidence that stimulant drugs do not improve the academic performance of ADHD-diagnosed students. Moreover, numerous studies have found little or no benefit of stimulants on neuropsychological tests of ADHD-diagnosed as well as normal, individuals. This paper examines the apparent paradox: why don't drugs that improve “attention,” produce better academic outcomes in ADHD-diagnosed students? We found that stimulant drugs significantly improved impairment of episodic memory in ADHD-diagnosed undergraduate students. Nevertheless, we also found consistent academic deficits between ADHD students and their non-ADHD counterparts, regardless of whether or not they used stimulant medications. We reviewed the current literature on the behavioral effects of stimulants, to try to find an explanation for these conflicting phenomena. Across a variety of behavioral tasks, stimulants have been shown to reduce emotional reactions to frustration, improve the ability to detect errors, and increase effortful behavior. However, all of these effects would presumably enhance academic performance. On the other hand, the drugs were also found to promote “risky behavior” and to increase susceptibility to environmental distraction. Such negative effects, including the use of drugs to promote wakefulness for last minute study, might explain the lack of academic benefit in the “real world,” despite their cognitive potential. Like many drugs, stimulants influence behavior in multiple ways, depending on the environmental contingencies. Depending on the circumstances, stimulants may, or may not, enhance cognition.

Co-segregation of hyperactivity, active coping styles, and cognitive dysfunction in mice selectively bred for low levels of anxiety

“…These results indicate that these traits might be co-selected but regulated by different neurobiological mechanisms (e.g., increased locomotor activity per se does not account for decreased immobility in the TST). This is in line with results of clinical studies where psychostimulants exert paradoxical motor calming effects, but fail to reverse cognitive dysfunctions (Advokat, 2010) or improve the academic achievement (Advokat and Scheithauer, 2013) in ADHD patients. In rats, administration of amphetamine at low doses is able to restore attention in the PFC-lesioned rats.…”

Acute and long-term effects of adolescent methylphenidate on decision-making and dopamine receptor mRNA expression in the orbitofrontal cortex

“…MPH is widely used as a performance enhancing drug in humans in late adolescence/early adulthood (high school/college-aged) to help focus attention and maintain concentration to enhance academic performance [9,10]. While there is evidence that MPH can improve declarative memory [43] and cognitive control [44] in college students, it is important to note that nonmedical users tend to have lower grade point averages [45], calling into question the long term success of such use.…”

“…Additionally, MPH has an affinity for blocking norepinephrine and serotonin transporters, albeit less than for dopamine [7,8]. Due to its pharmacological profile and ease of access, MPH is also recreationally misused in non-clinical adolescent populations [9]. While the most common motive for nonmedical use of stimulant medications is to enhance cognitive and/or academic functioning among college students, they are also misused for their ability to produce a characteristic “high” at larger doses [10].…”

Memory consolidation — Mechanisms and opportunities for enhancement

“…It has also been found to improve memory encoding [50] and consolidation in humans [51] and has therapeutic potential to rectify memory de cits in patients with multiple sclerosis It is also interesting to note that administration of both moda nil and amphetamine results in increased number of ripples during subsequent SWS [58]. This has been thus far attributed to 'rebound' of ripples following the increased wakefulness caused by these stimulant drugs.…”