Some of these stimulants are often used/misused by learners and students as cognitive performance enhancers. Do a search on the internet and compile a report on the merits/dangers of this practice.   

During a study where Methylphenidate (MPH), Modafinil & Caffeine were compared to placebos in three different arms; the following results were observed: 

Following the intake of MPH – declarative memory performance was significantly better, an effect that was also shown previously both for the dose of 20mg that was used in the trial and for a higher dose of 40mg (Linssen et al. 2012 & -2014). During the trial, early- as well as late recall was better after intake of the 20mg dosage of MPH. 

However interestingly enough no effects were seen on other cognitive tasks that were applied to test for a variety of cognitive domains – including a test for sustained attention. 

The positive results from the MPH intake are also correlated to studies done with amphetamines. 

The summarized results of the above-mentioned study showed that MPH intake had positive effects on fatigue and long-term declarative memory and caffeine showed positive effects on sustained attention; whereas Modafinil showed no significant effects. According to this study, no negative effects on other cognitive domains were observed. 

Repantis, D., Bovy, L., Ohla, K.  et al.  Cognitive enhancement effects of stimulants: a randomized controlled trial testing methylphenidate, modafinil, and caffeine.  Psychopharmacology 238, 441-451 (2021).  https://doi.org/10.1007/s00213-020-05691-w  

In contradiction – another study by researchers from the University of California, Irvine, states that using stimulants to enhance cognitive performance only bring about short term benefits – but in the long term, these drugs negatively affect focus, working memory, and sleep quality thus creating a “vicious cycle”. 

“Focus boosting drugs not worth the risks, studies warn” ~ Maria Cohut PhD 

https://www.medicalnewstoday.com/articles/326023  

The boost in attention after taking the drug is short-lived: the above-mentioned study compared groups of participants where one group received a placebo, and another group received 20mg of dextroamphetamine, the active ingredient present in Adderall. Results showed that the group who received the stimulant demonstrated improved short term attention than the group who had received the placebo. 75 minutes after receiving the drug, the cognitive performance was 4% better than that of the control group and they also had better focus than they did at baseline. However, at both 12 and 24 hours after taking this drug, participants no longer experienced any benefits. 

“Our research suggests that the purported enhancement to executive function from psychostimulants in healthy populations may be somewhat exaggerated, as we found only minor daytime improvement in attention and no benefit to working memory.” Sara Mednick. 

These stimulants in the long run cause adverse effects on memory and sleep – decreasing the patient’s total sleep time and sleep quality. Another consequence of long-term use is dependence. 

Other long term side effects include: 

• Tachycardia, high blood pressure and possible inflammation of heart valves

• Skin disorders, vitamin deficiency and flushed / pale skin

• Stomach ulcers and malnutrition

• Mental health and behavioural problems 

• Dizziness and difficulty breathing

• Loss of coordination and physical collapse

• Unusual tiredness / weakness

• Repetitive physical actions 

• Convulsions, coma and death 

Even though these stimulants have somewhat beneficial effects on cognitive function – especially short term and thus could improve memory and concentration during exams – misuse of these drugs could quickly deteriorate to dependence and in the long-term negatively affect users’ sleep and cognitive performance.