Neurocognitive enhancement or impairment? A systematic meta-analysis of prescription stimulant effects on processing speed, decision-making, planning, and cognitive perseveration

Increasing numbers of adults, particularly college students, are misusing prescription stimulants primarily for cognitive/academic enhancement, so it is critical to explore whether empirical findings support neurocognitive benefits of prescription stimulants. Previous meta-analytic studies have supported small benefits from prescription stimulants for the cognitive domains of inhibitory control and memory; however, no meta-analytic studies have examined the effects on processing speed or the potential impairment on other domains of cognition, including planning, decision-making, and cognitive perseveration. Therefore, the present study conducted a meta-analysis of the available literature examining the effects of prescription stimulants on specific measures of processing speed, planning, decision-making, and cognitive perseveration among healthy adult populations. The meta-analysis results indicated a positive influence of prescription stimulant medication on processing speed accuracy, with an overall mean effect size of g = 0.282 (95% CI [0.077, 0.488]; n = 345). Neither improvements nor impairments were revealed for planning time, planning accuracy, advantageous decision-making, or cognitive perseveration; however, findings are limited by the small number of studies examining these outcomes. Findings support that prescription stimulant medication may indeed act as a neurocognitive enhancer for accuracy measures of processing speed without impeding other areas of cognition. Considering that adults are already engaging in illegal use of prescription stimulants for academic enhancement, as well as the potential for stimulant misuse to have serious side effects, the establishment of public policies informed by interdisciplinary research surrounding this issue, whether restrictive or liberal, is of critical importance

The Relationship between ADHD Symptomology, Executive Functions, Morality, and Humor

Attention-deficit/hyperactivity disorder (ADHD) is characterized by a persistent pattern of inattention and impulsivity/hyperactivity and is estimated to affect 3% to 7% of the school population (American Psychiatric Association, 2000). In the majority of cases the disorder persists into adolescence and adulthood (Barkley, Murphy, & Fischer, 2008; Simon, Czobor, Bálint, Mészáros & Bitter, 2009). Although many studies have reported on the relationship between ADHD and younger children, there are fewer studies examining this with older participants. Recent research indicates that increasing numbers of high school students with ADHD are pursuing college (Wolf, Simkowitz, & Carlson, 2009). While the exact rates of ADHD among college students are unknown, approximately 2% to 4% of college students report clinically significant levels of ADHD symptomology (Weyandt & DuPaul, 2006). Even though various studies in recent years have focused on unique aspects of functioning among college students diagnosed with ADHD, less empirical evidence is available concerning how these aspects of functioning specifically relate to ADHD symptomology in college students

Neuroimaging and ADHD: FMRI, PET, DTI findings, and methodological limitations

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by pervasive and developmentally inappropriate levels of inattention, impulsivity, and hyperactivity. There is no conclusive cause of ADHD although a number of etiologic theories have been advanced. Research across neuroanatomical, neurochemical, and genetic disciplines collectively support a physiological basis for ADHD and, within the past decade, the number of neuroimaging studies concerning ADHD has increased exponentially. The current selective review summarizes research findings concerning ADHD using functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and diffusion tensor imaging (DTI). Although these technologies and studies offer promise in helping to better understand the physiologic underpinnings of ADHD, they are not without methodological problems, including inadequate sensitivity and specificity for psychiatric disorders. Consequently, neuroimaging technology, in its current state of development, should not be used to inform clinical practice. © 2013 Copyright Taylor and Francis Group, LLC

Prescription Stimulant Misuse and ADHD Symptomatology Among College Students in Iceland

Objective: Misuse of prescription stimulant medication is a prevalent problem on American college campuses; however, few studies have been conducted beyond the United States. Although Iceland has the highest methylphenidate prescription rates in the world, prevalence of stimulant misuse within the Icelandic college student population remains to be investigated. Method: We examined the prevalence of prescription stimulant misuse among N = 521 college students in Iceland, using an online survey. Results: Overall prevalence of lifetime stimulant misuse was approximately 13%; 11% among participants without a prescription for stimulant medication, and 42% among participants holding a prescription. The primary reported reason for misuse was academic enhancement; risk factors included male sex, anxiety symptoms, and ADHD symptomatology. Conclusion: The present findings have implications for public health policy in Iceland, particularly as it relates to the college population. Prevention and intervention programs that provide college students with safer strategies to manage academic demands are warranted

Attention-Deficit Hyperactivity Disorder: Clinical Considerations for Women

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by hyperactivity, impulsivity, and/or inattention. Women with ADHD represent a particularly vulnerable group, given their increased risk for psychosocial and parenting difficulties. Women\u27s health care clinicians should expect to encounter women with diagnosed and undiagnosed ADHD that may or may not be treated. Pharmacologic intervention, namely, prescription stimulants, is an important consideration for pregnant and breastfeeding women with ADHD, especially because the US Food and Drug Administration has determined that there is not enough information to confirm either harm or lack of harm to the developing fetus following exposure to these drugs. Due to the increase in use of prescription stimulants without a prescription, clinicians are also likely to encounter women misusing stimulants for a variety of reasons. This article provides an overview of ADHD diagnosis, outlines effective treatment options, and offers insight into the importance for clinicians to consider prescription stimulant misuse. Guidance concerning treatment of ADHD during pregnancy and lactation is reviewed

Pharmacological Interventions for Adolescents and Adults with ADHD: Stimulant and Nonstimulant Medications and Misuse of Prescription Stimulants

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity that cause functional impairment. Recent research indicates that symptoms persist into adulthood in the majority of cases, with prevalence estimates of approximately 5% in the school age population and 2.5%–4% in the adult population. Although students with ADHD are at greater risk for academic underachievement and psychosocial problems, increasing numbers of students with ADHD are graduating from high school and pursuing higher education. Stimulant medications are considered the first line of pharmacotherapy for individuals with ADHD, including college students. Although preliminary evidence indicates that prescription stimulants are safe and effective for college students with ADHD when used as prescribed, very few controlled studies have been conducted concerning the efficacy of prescription stimulants with college students. In addition, misuse of prescription stimulants has become a serious problem on college campuses across the US and has been recently documented in other countries as well. The purpose of the present systematic review was to investigate the efficacy of prescription stimulants for adolescents and young adults with ADHD and the nonmedical use and misuse of prescription stimulants. Results revealed that both prostimulant and stimulant medications, including lisdexamfetamine dimesylate, methylphenidate, amphetamines, and mixed-amphetamine salts, are effective at reducing ADHD symptoms in adolescents and adults with ADHD. Findings also suggest that individuals with ADHD may have higher rates of stimulant misuse than individuals without the disorder, and characteristics such as sex, race, use of illicit drugs, and academic performance are associated with misuse of stimulant medications. Results also indicate that individuals both with and without ADHD are more likely to misuse short-acting agents than long-acting agents. These findings have implications for intervention, prevention, and future research

Physiological substrates of executive functioning: a systematic review of the literature

Executive function (EF) is a multifaceted construct that has been defined as a set of higher-order cognitive processes that allow for flexibility, self-regulation, strategic planning, and goal-directed behaviors. EFs have been studied in numerous clinical disorders using a variety of neuropsychological tasks and, more recently, neuroimaging techniques. The underlying physiological substrates of EF were historically attributed to the frontal lobes; however, recent studies suggest more widespread involvement of additional brain regions. The purpose of the present study was to conduct a systematic review (using PRISMA 2009 guidelines) of neuroimaging studies employing functional magnetic resonance imaging and diffusion tensor imaging methods investigating the physiological substrates of EFs in attention-deficit/hyperactivity disorder compared to other clinical groups and non-clinical participants. Research articles were retrieved using PsycINFO, PsycARTICLES, MEDLINE, and ScienceDirect, beginning February 2015 through May 2016. A total of 42 studies met eligibility. Of those 42 studies, 22 studies included clinical participants and 20 studies included non-clinical participants. Results revealed increased activation of the frontal brain region in the majority of non-clinical studies and approximately 50% of the clinical studies, albeit with some inconsistencies across subregions, tasks, and age groups. Implications, methodological limitations, and suggestions for future research are discussed