Neurocognitive Effects of Substance Abuse and Their Measurement with Neuropsychological Tests

Regular drug use, whether socially accepted, such as alcohol, tobacco, recreational cannabis, or self-prescribed medication abuse, or illicit, such as cocaine, heroin, and synthetic drugs, among others, has the potential to significantly affect the quality of life, health, and overall normal cognitive functioning. Unfortunately, intensive or chronic use often develops into a substance use disorder, leading to clinical conditions that can affect brain structures and, thus, the proper functioning of cognitive abilities and human behavior. This phenomenon is commonly referred to as the neuropsychological consequences of chronic drug use. In this regard, the latest World Drug Report 2023 makes a strong appeal to governments and the general population about the alarming increase of 23% in the use of narcotic drugs compared to the previous report. This means that 5.8% of the world’s population between the ages of 15 and 64 are chronic drug users. Therefore, this chapter will analyze the main substances that can affect brain function and the underlying neurocognitive processes. Neurophysiological events, controlled by the prefrontal cortex, allow a person to receive information and classify, process, and structure a response plan and program; this series of events is commonly referred to as executive functions. In addition to these complex cognitive processes, adaptive functioning and behavior can be altered by excessive drug use. On the other hand, a wide variety of neuropsychological tests with robust scientific support are reviewed, tests that may be available to clinicians, whether medically or nonmedically oriented, who wish to ascertain the status of neurocognitive functions affected by chronic and severe substance abuse.