Cognitive Casualties: How Drugs Can Lead to Long-Term Deficiencies in Cognition

Olivia de Moraes and Dillon Murphy

Drugs like alcohol, cannabis, cocaine, and ecstasy can produce positive emotional effects such as increased sociability, reduced stress and anxiety, intense pleasure, feelings of euphoria, increased energy, and temporary wellbeing. Although these effects may sound desirable, these benefits often come at a severe cost to many cognitive processes (Kroon et al., 2021) and the usage of these drugs can have lasting consequences that remain even after abstinence (Klugman & Gruzelier, 2003). Because initial exposure and continued use appear most frequently in adolescents and young adults (Strote et al., 2002), understanding the severity and lasting impacts of drug use may help prevent harmful consequences from occurring and dissuade individuals from using these substances.

Under the guise of temporary enjoyment and lessened inhibitions, alcohol is an enticing drug for people of all ages. Especially for college students, excessive drinking continues to be a concern due to their newfound freedom, lessened parental control, and changing attitudes regarding drinking (Krieger et al., 2018). Whether consistently drinking or having one-night binges, exorbitant use of alcohol can lead to serious detriments in cognitive abilities. For example, Czapla et al. (2015) compared the performance of diagnosed alcoholics to healthy controls on various cognitive tasks. Results revealed that alcohol-dependent patients had poorer sustained attention, longer response times, and difficulty with executive functions like planning, learning, and self-control. Additionally, other work has illustrated the next-day consequences (when participants were sober) following heavy alcohol consumption, which can include deficits in short- and long-term memory, psychomotor skills, and sustained attention (Gunn et al., 2018). Together, these results suggest that, in addition to the obvious impairments occurring while intoxicated, alcohol can compromise cognition in the days following heavy consumption.

Like alcohol, cannabis has enticing qualities such as induced joy and reduced stress, but its effects can also linger past the point of inebriation and lead to long-term deficits in cognitive processes. For example, prior work has demonstrated impairments in cognitive impulsivity (difficulty with delayed gratification), cognitive flexibility (the ability to quickly attend to different tasks), sustained attention, as well as short- and long-term memory when cannabis users are sober (Figueiredo et al., 2020). Furthermore, Lorenzetti et al. (2020) measured how the cognitive performance of adolescent cannabis users was impacted in their adult life. Results revealed larger declines in IQ for cannabis users compared with non-users, users were less likely to complete secondary school, and users had notable difficulty with focusing and memory. Thus, cannabis can have long-term effects that remain even when sober and could potentially obstruct an individual’s future success.

Cocaine is another popular drug, particularly in younger populations (Liu et al., 2019), with lasting cognitive, behavioral, and neural consequences. For example, cognitive flexibility, verbal fluency (producing as many words related to a given subject as possible), and memory suffer for cocaine users even when sober (Kelley et al., 2005). Additionally, there are permanent changes to the brain, such as reduced gray matter and structural alterations in various regions (i.e., the orbitofrontal cortex, insula, amygdala, and temporal cortex) that may contribute to some of these cognitive consequences (Jedema et al., 2021). Thus, cocaine can impair cognitive functioning, and the long-term effects tend to be irreversible due to the permanent changes in the brain.

Shifting to another popular drug, ecstasy has similar cognitive consequences to cocaine and alcohol. For example, previous work has revealed impaired performance on memory and attention tasks in chronic ecstasy users (Rodgers, 2000). Additionally, a 2-year longitudinal study revealed that recreational ecstasy users (with maintained or variable use) demonstrated persistent impairments in verbal fluency, working memory, and processing speed, with heavier users also showing an inability to remember many personal life events (de Sola Llopis et al., 2008). Moreover, Klugman and Gruzelier (2003) demonstrated that ecstasy can impair performance on complex memory tasks and higher-level informational processing (multidimensional executive and control processes). Collectively, these findings suggest that the cognitive impairments caused by using ecstasy are long-term, especially with continued use.

While there can be many permanent cognitive consequences if users continually use drugs like alcohol, cannabis, cocaine, and ecstasy, some of the negative effects appear to be temporary and can improve with committed abstinence. For example, attentional impairments can significantly improve after two weeks of refraining from cannabis (Wallace et al., 2020), and short-term memory may also recover (Kroon et al., 2021). Additionally, impaired cognitive flexibility induced by cocaine can improve with sobriety (Kelley et al., 2005). However, while some abilities can regenerate after an individual becomes sober, other effects often do not recover after dedicated abstinence. According to Kelley et al. (2005), chronic cocaine users still showed deficits in verbal fluency and verbal memory even after a period of abstinence. Because of the inability to socially connect due to these cognitive impairments, the resulting long-term effects can lead to prolonged substance abuse, a higher likelihood of relapsing, and depression. As a result, it is easy to fall victim to these substances, and abstinence can be difficult. The bright side is that there are many available resources that can help addicted users, such as the Substance Abuse and Mental Health Services Administration, which has a 24 hour helpline in case of emergencies!

To conclude, there can be significant and lasting negative effects of alcohol, cannabis, cocaine, and ecstasy on cognitive abilities. These can include but are not limited to reduced memory performance, attentional deficits, slower reaction times, and impaired word processing. Thus, people should carefully determine the worth of using drugs as the associated cognitive impairments (among other damaging effects to the user’s health, like the substances’ addictive properties) could hinder their future. As a society, we need to provide accurate information about the cognitive consequences of drug use to educate potential users about possible enduring effects. Together, research on the use of alcohol, cannabis, cocaine, and ecstasy suggests that if these drugs are used, they should be used with extreme caution and awareness of the potential permanent cognitive impairments.




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