The Effect of Stimulants on Cognitive Functions

Abstract 

Stimulants are commonly used for narcolepsy and attention deficit hyperactivity disorder (ADHD). The stimulating effects of these prescription drugs include an increase in alertness, energy, and may be highly effective for its performance enhancing effect. However, these stimulants may also be highly incompetent among those suffering from ADHD. The detrimental effects possibly range from depression and anxiety to addiction, abuse, and depletion of cognitive functions. Therefore, it is relatively important to determine the pattern of long and short term benefits/drawbacks of stimulants on mental health among ADHD patients. Recent studies have indicated an increase in prescriptions for stimulants to treat ADHD. Due to the lack of non-medicated treatments, scientists and psychiatrists are monitoring the effects of these stimulants on the cognitive process. The review addresses the effects, if any, of stimulants on the brain of ADHD patients. 

Introduction

Stimulants have been prescribed to ADHD patients over several decades. These stimulants are inclusive of amphetamines and methylphenidate typically the most clinically used for this disorder. The use of stimulant drugs has been one of the most widespread pharmacological treatments for children with attention deficit hyperactivity disorder (Swanson, 2011). Changes in cognitive function may be a result of changes in the level of dopamine in the brain. Dopamine is known as the chemical that sends signals to the brain. The brain often adapts to the effects of dopamine produced by the stimulant drug (Miller). Once the brain adapts, stimulants may be effective or ineffective depending on the patient. 

Stimulants are used extensively as a drug to manage impulsive behavior, hyperactivity, and attention span. The brain may react differently depending on the stimulant. Stimulants are rather popular among ADHD patients due to the lack of non-medicated treatments. Some patients prefer the natural route to reducing ADHD symptoms; however the results may be impartial. Non pharmaceutical alternatives are rarely used. The demand for prescription stimulants has increased, particularly for adults. The increase in stimulant use has prompted both psychologists and scientists to perform studies to investigate the effects of stimulants on cognitive functions.  

Laboratory Testing and Results 

Laboratory studies have been conducted for the past decade to understand cognitive issues on ADHD patients. Using neuroimaging technique and magnetic resonance imaging (MRI), scientists have allowed examination of the brain. In a structural study, ADHD patients with and without medication use were compared to non ADHD, non-medicated groups. The medicated groups were given different dosages of stimulants (Spencer, 2013). The results of the neuroimaging studies indicated that scientists Castellanos and Pliszka could not detect medication differences in the brain. There were no reductions in the cerebellar volume of the cerebellum. The sensory system and motor movements of the brain remained functional. Furthermore, the total caudate volume of the brain and basal ganglia volumes were unaffected. Both serve as the main cognition in the brain. If these are affected, there may be errors in the senses. There were no evident differences in ADHD medicated groups and ADHD non medicated groups. 

In another experiment, evidence from neuropsychological studies were used to describe how stimulant medications may affect brain processes in ADHD patients. The main focus was the patient’s reaction time and response to stimulus in both signals and surroundings (Swanson, 2011). The laboratory measured impulsivity and attention of medicated ADHD patients using the Go-NoGo task, a computerized test that allows an individual to monitor activity. The task communicated an increase in the use of the posterior cingulate, parietal cortex, and caudate nucleus. This suggests that stimulants may actually enhance the function of the brain. This prompted laboratories to use positron emission tomography (PET) studies to detect the results of stimulants on cognitive functions. PET imaging displays an increase in blood flow of the brain and brain metabolism. Stimulants may improve performance among ADHD patients. 

Dosage Effect

Some scientists do believe that stimulant medication may have a long term effect even though some studies have disputed the idea. According to Caroline Miller, increasing the dosage on stimulants could possibly affect the brain (Miller). The brain needs time to adapt to changes in medication especially when the dopamine is targeted. If stimulants are given to children with ADHD in the earlier stages of childhood, the brain might adapt quickly. If the brain adapts quickly to the medication, it will enhance brain function for ADHD patients. Doses for stimulants vary for each patient and the optimal dose may affect cognitive functions (Swanson, 2011). It is possible that higher doses can enhance performance and it is also possible that lower doses can have full cognitive enhancement depending on the patient. 

Conclusion 

Stimulants are being used to manage attention deficit hyperactivity disorder (ADHD). Scientists have conducted many studies to understand the connection between stimulants and cognitive function. Many studies have indicated that there is no short term connection between stimulants and depletion of cognitive functions in ADHD patients. Despite these findings, scientists worry that the long term effects may be a result of the dosage of the stimulant. Depending on the patient, the dosage can either enhance or reduce cognitive function. 

References

Miller, C., & Child Mind Institute. (n.d.). What We Know About the Long-Term Effects of ADHD Medications. Retrieved from https://childmind.org/article/know-long-term-effects-adhd-medications/

Spencer, T. J., Brown, A., Seidman, L. J., Valera, E. M., Makris, N., Lomedico, A., … Biederman, J. (2013, September). Effect of psychostimulants on brain structure and function in ADHD: a qualitative literature review of magnetic resonance imaging-based neuroimaging studies. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3801446/

Swanson, J., Baler, R. D., & Volkow, N. D. (2011, January). Understanding the effects of stimulant medications on cognition in individuals with attention-deficit hyperactivity disorder: a decade of progress. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055506/