Prescription stimulants in individuals with and without attention deficit hyperactivity disorder: misuse, cognitive impact, and adverse effects

The effects of adolescent methylphenidate exposure on the behavioral and brain-derived neurotrophic factor response to nicotine

This study analyzed the interaction of adolescent methylphenidate on the behavioral response to nicotine and the effects of these drug treatments on brain-derived neurotrophic factor in the nucleus accumbens and hippocampus in male and female Sprague-Dawley rats. Animals were intraperitoneal administered 1 mg/kg methylphenidate or saline using a "school day" regimen (five days on, two days off) beginning on postnatal day (P)28 and throughout behavioral testing. In Experiment 1, animals were intraperitoneal administered 0.5 mg/kg (free base) nicotine or saline every second day for 10 days from P45-P63 and tested after a three-day drug washout on the forced swim stress task on P67-P68. Results revealed that adolescent methylphenidate blunted nicotine behavioral sensitization. However, methylphenidate-treated rats given saline during sensitization demonstrated decreased latency to immobility and increased immobility time on the forced swim stress task in males that was reduced by nicotine. In Experiment 2, a different set of animals were conditioned to nicotine (0.6 mg/kg free base) or saline using the conditioned place preference behavioral paradigm from P44-P51, and given a preference test on P52. On P53, the nucleus accumbens and hippocampus were analyzed for brain-derived neurotrophic factor. Methylphenidate enhanced nicotine-conditioned place preference in females and nicotine produced conditioned place preference in males and females pre-exposed to saline in adolescence. In addition, methylphenidate and nicotine increased nucleus accumbens brain-derived neurotrophic factor in females and methylphenidate enhanced hippocampus brain-derived neurotrophic factor in males and females. Methylphenidate adolescent exposure using a clinically relevant dose and regimen results in changes in the behavioral and brain-derived neurotrophic factor responses to nicotine in adolescence that are sex-dependent.

Personal and perceived peer use and attitudes towards the use of nonmedical prescription stimulants to improve academic performance among university students in seven European countries

BACKGROUND

Overestimations of non-prescribed stimulant use of peers are well documented in the USA and have also been identified as predictive of personal stimulant consumption. This study aimed to examine whether overestimations of peer use and approval of the use are associated with personal use and attitude towards the use of non-prescribed stimulants among European university students.

METHOD

The EU funded 'Social Norms Intervention for the prevention of Polydrug usE (SNIPE)' study was conducted in seven European countries. In a web-based questionnaire, 4482 students were asked about their personal use and their attitude towards non-prescribed stimulant use, as well as the perceived peer use and peer attitude.

RESULTS

59% of students thought that the majority of their peers used non-prescribed stimulants more frequently than themselves, and only 4% thought that the use of the majority was lower than their personal use. The perception that the majority of peers had used non-prescribed stimulants at least once was significantly associated with higher odds for personal use of non-prescribed stimulants (OR: 3.30, 95% CI: 2.32-4.71). In addition, the perception that the majority of peers approved of the non-prescribed use of stimulants was associated with a 4.03 (95% CI: 3.35-4.84) times higher likelihood for personal approval.

DISCUSSION

European university students generally perceived the non-prescribed use of stimulants of peers to be higher than their personal use. This perception, as well as a perception of higher approval in the peer group, was associated with a higher likelihood of personal non-prescribed stimulant medication use and approval.

Substance Use as a Risk Factor for Sleep Problems Among Adolescents Presenting to the Emergency Department

OBJECTIVES

To determine correlates of sleep problems among adolescents. Specifically, to assess the relative strength of associations between sleep problems and dating victimization, reasons for emergency department (ED) visit, depression, unhealthy alcohol use, and other drug use (marijuana, nonmedical use of prescription opioids, stimulants, and tranquilizers).

METHODS

A total of 1852 adolescents aged 14 to 20 years presenting for care to the University of Michigan Emergency Department, Ann Arbor, Michigan, during 2011-2012, self-administered a computerized health survey. Sleep problems were identified if any of the 4 items on the Sleep Problems Questionnaire were rated by a patient as greater than 3 on a 0 to 5 scale. Adolescents who were too sick to be screened in the ED were eligible to participate in the study during their inpatient stay. Exclusion criteria for baseline included insufficient cognitive orientation precluding informed consent, not having parent/guardian present if younger than 18 years, medical severity precluding participation, active suicidal/homicidal ideation, non-English-speaking, deaf/visually impaired, or already participated in this study on a prior visit.

RESULTS

23.5% of adolescents reported clinically significant sleep problems. Female gender, depression, dating victimization, tobacco use, nonmedical use of prescription medication, and an ED visit for medical reasons were each associated with sleep problems among adolescents, even while controlling for age, other types of drug use, receiving public assistance, and dropping out of school.

CONCLUSIONS

These exploratory findings indicate that ED-based screening and brief intervention approaches addressing substance use and/or dating victimization may need to account for previously undiagnosed sleep problems.

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. (PsycINFO Database Record

A possible effect of methylphenidate on state anxiety: A single dose, placebo controlled, crossover study in a control group

Methylphenidate affects state-anxiety in ADHD patients. The current study examines the effect of Methylphenidate on state-anxiety in healthy subjects. In a cross-over, randomized, controlled, double-blind study, 36 healthy subjects received either Methylphenidate or placebo. As a group, no change in state-anxiety was detected with Methylphenidate. However, participants reporting higher anxiety levels experienced a significant and specific state-anxiety reduction following Methylphenidate. Moreover, a strong negative correlation was found between the initial-level of anxiety and net-change in state-anxiety. These changes were unrelated to self-perceived attention levels. Our results point to the state-dependent effects of Methylphenidate on anxiety.

Lisdexamfetamine in the treatment of moderate-to-severe binge eating disorder in adults: systematic review and exploratory meta-analysis of publicly available placebo-controlled, randomized clinical trials

BACKGROUND

Preliminary placebo-controlled evidence paved the ground to the US Food and Drug Administration approval extension of lisdexamfetamine for the treatment of moderate-to-severe binge eating disorder (BED) in adults.

OBJECTIVES

To provide a preliminary qualitative and quantitative synthesis of the placebo-controlled, randomized clinical trials (RCTs) considering the efficacy and tolerability of lisdexamfetamine in the acute and/or maintenance treatment of moderate-to-severe BED in adults.

METHODS

A preliminary, yet comprehensive, systematic review was performed by accessing a broad range of resources providing publicly available data about lisdexamfetamine at the time of inquiry (March 2016). Study eligibility criteria, participants, and interventions were considered focusing on major clinical and functional outcomes of either efficacy or tolerability of lisdexamfetamine in the treatment of moderate-to-severe BED in adults.

RESULTS

Meta-analysis of data pooled from three acute RCTs significantly favored lisdexamfetamine over placebo in the reduction of binge eating days/week, Yale-Brown Obsessive Compulsive Scale Modified for Binge Eating total score, weight, response, and remission rates (all, P≤0.01). In contrast, discontinuation rates due to treatment-emergent adverse events were significantly higher among patients in receipt of lisdexamfetamine (relative risk 2.19, P=0.04) versus placebo.

LIMITATIONS

Publication, selection, performance, attrition, reporting, sponsorship, and "diagnostic shift" biases. Lack of inclusion of adverse event effects other than those requiring discontinuation of the trial(s), as well as lack of information about clinically relevant psychiatric or other medical comorbidities, limits the overall generalizability of pooled results.

CONCLUSION

Across the included acute phase RCTs, lisdexamfetamine (at 30, 50, or 70 mg/day) led to significant reduction in a number of clinically relevant outcomes compared to placebo. Moreover, safety concerns related to adverse events, high discontinuation rates, and the need for additional long-term maintenance of RCTs solicit careful monitoring of the drug in terms of overall safety and tolerability by further RCTs.

Prevalence and correlates of non-medical stimulants and related drug use in a sample of South African undergraduate medical students

BACKGROUND

The non-medical use of prescription psychostimulants or cognitive-enhancing substances among healthy college students is a growing concern. This use appears to be particularly high among medical students. To our knowledge, no literature is available on the non-medical use of stimulants among South African medical students.

OBJECTIVE

To determine the prevalence and correlates of non-medical stimulant use as well as subjective opinion on peer numbers using stimulants and university attitude towards stimulant use among a sample of South African undergraduate medical students.

METHODS

A descriptive observational study was conducted by means of a self-report questionnaire. Second- and fourth-year medical students (n = 252) completed the questionnaire.

RESULTS

Of the sample, 44 (18%) reported a lifetime use of stimulants for non-medical purposes and 33 (85%) of this group reported use within the past year. A total of six (2%) students reported a diagnosis of Attention Deficit/Hyperactivity Disorder (ADHD). In the group without a diagnosis of ADHD, non-medical stimulant use was associated with the year of study (p = 0.03) and illicit substance use (p = 0.01). Most of the students in this group (31, 32%) reported using stimulants to improve concentration.

CONCLUSION

Non-medical use of stimulants to improve concentration and academic performance is prevalent among the South African medical students sampled in this study. Further research at other institutions and under non-medical students would be helpful to assess the scope of this phenomenon.

Recent Trends in Stimulant Usage

OBJECTIVE

In the last decade, dramatic changes have occurred in stimulant medication prevalence and in patterns of stimulant treatment. The resultant trends merit analysis.

METHOD

Usage patterns of stimulant medication, specifically amphetamine and methylphenidate, were analyzed for trends. The data were obtained from datasets including pharmacy claims, aggregate production quotas, bulk distribution to counties, pharmacy prescription sales, parent surveys, and physician visit surveys. Stimulant medication trends were organized by drug subclass, year, age group, gender, country, prescriber specialty, diagnosis, and expenditures.

RESULTS

Major recent trends are as follows: amphetamine medication usage has prominently surpassed methylphenidate, total stimulant prescription sales to adults have surpassed those for youth, and more adult women are prescribed stimulants than adult men.

CONCLUSION

Stimulant medication treatment-particularly of amphetamines-is rapidly expanding in the United States. Off-label use is reported to be at least 40% of total use and appears to be more common in adults. (J. of Att. Dis. 2016; 20(6) 471-477).

Atomoxetine-related Takotsubo Cardiomyopathy

Many psychotropic medications target norepinephrine receptors, which can have serious cardiovascular implications, especially in the context of overdoses, polypharmacy, and high-risk populations. This article presents the case of a patient with adult attention-deficit/hyperactivity disorder who developed takotsubo cardiomyopathy subsequent to pharmacokinetic and pharmacodynamic interactions between atomoxetine, a selective norepinephrine reuptake inhibitor, and fluoxetine. Clinicians should be mindful of the potential for cardiovascular adverse effects when prescribing agents that target noradrenergic receptors.

Adult ADHD: A new disease?

OBJECTIVES

Until recently, it was believed that attention deficit and hyperactivity disorder (ADHD) are outgrown by the end of adolescence and the beginning of adulthood. The purpose of this review is to describe the characteristics of the disease in adults, depict comorbidities that accompany it, and expand the scope over methods of diagnosis and treatment of these ages.

METHODS

A search was conducted in the PubMed/MEDLINE database for relevant key words 'ADHD', 'attention deficit', 'hyperactivity' and 'adult'. Secondary search parameters were 'comorbid', 'prevalence', 'epidemiology', 'therapy' and 'drug therapy'. Search was limited to 'English' and 'Humans'.

RESULTS

Over the years, the persistent nature of the disorder has been clarified, elucidating prevalence rate, gender differences and subtype shifts among adult ADHD population. Nevertheless, even today, there is only limited awareness of the existence of the disorder across one's lifespan, its consequences and the appropriate treatment.

CONCLUSIONS

Our results emphasise the growing awareness of adult psychosocial impairments due to ADHD symptoms and comorbidities, as well as the need for further collaboration among practitioners and mental health-care professionals to better identify the condition and allow for effective treatment.

Prescription stimulant use is associated with earlier onset of psychosis

A childhood history of attention deficit hyperactivity disorder (ADHD) is common in psychotic disorders, yet prescription stimulants may interact adversely with the physiology of these disorders. Specifically, exposure to stimulants leads to long-term increases in dopamine release. We therefore hypothesized that individuals with psychotic disorders previously exposed to prescription stimulants will have an earlier onset of psychosis. Age of onset of psychosis (AOP) was compared in individuals with and without prior exposure to prescription stimulants while controlling for potential confounding factors. In a sample of 205 patients recruited from an inpatient psychiatric unit, 40% (n = 82) reported use of stimulants prior to the onset of psychosis. Most participants were prescribed stimulants during childhood or adolescence for a diagnosis of ADHD. AOP was significantly earlier in those exposed to stimulants (20.5 vs. 24.6 years stimulants vs. no stimulants, p < 0.001). After controlling for gender, IQ, educational attainment, lifetime history of a cannabis use disorder or other drugs of abuse, and family history of a first-degree relative with psychosis, the association between stimulant exposure and earlier AOP remained significant. There was a significant gender × stimulant interaction with a greater reduction in AOP for females, whereas the smaller effect of stimulant use on AOP in males did not reach statistical significance. In conclusion, individuals with psychotic disorders exposed to prescription stimulants had an earlier onset of psychosis, and this relationship did not appear to be mediated by IQ or cannabis.

Prescription Stimulants and PTSD Among U.S. Military Service Members

Posttraumatic stress disorder (PTSD) is a prevalent condition among military service members and civilians who have experienced traumatic events. Stimulant use has been postulated to increase the risk of incident PTSD; however, research in this area is lacking. In this study, the association between receipt of prescription stimulants and PTSD was examined in a secondary analysis among active duty U.S. military members (n = 25,971), participating in the Millennium Cohort Study, who completed a baseline (2001-2003) and two follow-up surveys (between 2004-2008). Prescription stimulant data were obtained from the military Pharmacy Data Transaction Service. PTSD was assessed using the PTSD Checklist-Civilian Version and incident PTSD was defined as meeting the criteria at follow-up among those who did not have a history of PTSD at baseline. Overall, 1,215 (4.7%) persons developed new-onset PTSD during follow-up. Receipt of prescription stimulants were significantly associated with incident PTSD, hazard ratio = 5.09, 95% confidence interval [3.05, 8.50], after adjusting for sociodemographic factors, military characteristics, attention-deficit/hyperactivity disorder, baseline mental and physical health status, deployment experiences, and physical/sexual trauma. Findings suggested that prescription stimulants are associated with incident PTSD among military personnel; these data may inform the underlying pathogenesis of and preventive strategies for PTSD.

Attention-deficit/hyperactivity disorder, methylphenidate use and the risk of developing schizophrenia spectrum disorders: A nationwide population-based study in Taiwan

This study estimated the risk of developing psychotic disorders by comparing children with ADHD to non-ADHD controls, and to examine whether methylphenidate (MPH) treatment influences the risks of psychotic disorders. A nationwide cohort of patients who were newly diagnosed with ADHD (n=73,049) and age- and gender-matched controls (n=73,049) were selected from Taiwan's National Health Insurance database from January 2000 to December 2011. All participants were observed until December 31, 2011. Cox regression models were used to estimate the effects of ADHD diagnosis and MPH use on subsequent outcomes. Having a diagnosis of any psychotic disorder and of schizophrenia were set as two different outcomes and were analyzed separately. Compared to the control group, the ADHD group showed significantly increased risk of developing any psychotic disorder (adjusted hazard ratio [aHR], 5.20; 95% confidence interval [CI], 4.30-6.30) and schizophrenia (aHR, 4.65; 95% CI, 3.59-6.04). Compared to ADHD patients without psychosis, patients with ADHD who developed psychosis had significantly older age at first diagnosis of ADHD (9.4±3.3years vs. 10.6±4.0years). Among patients with ADHD, MPH use significantly increased the risk of developing any psychotic disorder (aHR, 1.20; 95% CI, 1.04-1.40), but did not increase the risk of developing schizophrenia (aHR, 1.16; 95% CI, 0.94-1.42). The results indicated that previous diagnoses of ADHD are a powerful indicator of developing psychotic disorders. Nevertheless, the specific mechanisms of the relationships between ADHD, MPH use and psychotic disorders need further elucidation in future clinical studies.

Bipolar disorder and ADHD: comorbidity and diagnostic distinctions

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) are neurodevelopmental disorders with onset in childhood and early adolescence, and common persistence in adulthood. Both disorders are often undiagnosed, misdiagnosed, and sometimes over diagnosed, leading to high rates of morbidity and disability. The differentiation of these conditions is based on their clinical features, comorbidity, psychiatric family history course of illness, and response to treatment. We review recent relevant findings and highlight epidemiological, clinical, family history, course, and treatment-response differences that can aid the differential diagnosis of these conditions in an outpatient pediatric setting.

Risk factors for high levels of prescription drug misuse and illicit drug use among substance-using young men who have sex with men (YMSM)

BACKGROUND

Limited research has focused on prescription drug misuse among young men who have sex with men (YMSM), or investigated risk factors contributing to misuse. This study aims to investigate the relationship between multiple psychosocial risk factors (i.e., childhood abuse, discrimination, mental health distress) and prescription drug misuse among YMSM who are current substance users.

METHODS

YMSM (N=191) who reported prescription drug misuse in the past 6 months were recruited in Philadelphia between 2012 and 2013 to complete an anonymous survey assessing demographic information, substance use, and psychosocial factors.

RESULTS

High levels of childhood physical abuse and perceived stress were associated with higher opioid misuse, while high levels of depression were associated with lower misuse of opioids. Those with higher levels of perceived stress were more likely to report higher tranquilizer misuse, while those with more experiences of social homophobia/racism and higher levels of depression and somatization reported higher stimulant misuse. Regarding demographic correlates, older participants were more likely than younger participants to report higher opioid misuse, while racial minorities were less likely than White participants to report higher misuse of tranquilizers, stimulants, and illicit drug use. Bisexual/heterosexual/other identified participants were more likely than gay identified participants to report higher misuse of all three classes of prescription drugs.

CONCLUSIONS

Associations of risk factors with substance use among YMSM are complex and offer opportunities for additional research. Our findings show that prevention efforts must address substance use among YMSM in sync with psychosocial stressors.

Treatment of toxicity from amphetamines, related derivatives, and analogues: a systematic clinical review

BACKGROUND

Overdose of amphetamine, related derivatives, and analogues (ARDA) continues to be a serious worldwide health problem. Patients frequently present to the hospital and require treatment for agitation, psychosis, and hyperadrenegic symptoms leading to pathologic sequelae and mortality.

OBJECTIVE

To review the pharmacologic treatment of agitation, psychosis, and the hyperadrenergic state resulting from ARDA toxicity.

METHODS

MEDLINE, PsycINFO, and the Cochrane Library were searched from inception to September 2014. Articles on pharmacologic treatment of ARDA-induced agitation, psychosis, and hyperadrenergic symptoms were selected. Evidence was graded using Oxford CEBM. Treatment recommendations were compared to current ACCF/AHA guidelines.

RESULTS

The search resulted in 6082 articles with 81 eligible treatment involving 835 human subjects. There were 6 high-quality studies supporting the use of antipsychotics and benzodiazepines for control of agitation and psychosis. There were several case reports detailing the successful use of dexmedetomidine for this indication. There were 9 high-quality studies reporting the overall safety and efficacy of β-blockers for control of hypertension and tachycardia associated with ARDA. There were 3 high-quality studies of calcium channel blockers. There were 2 level I studies of α-blockers and a small number of case reports for nitric oxide-mediated vasodilators.

CONCLUSIONS

High-quality evidence for pharmacologic treatment of overdose from ARDA is limited but can help guide management of acute agitation, psychosis, tachycardia, and hypertension. The use of butyrophenone and later-generation antipsychotics, benzodiazepines, and β-blockers is recommended based on existing evidence. Future randomized prospective trials are needed to evaluate new agents and further define treatment of these patients.

The impact of case definition on attention-deficit/hyperactivity disorder prevalence estimates in community-based samples of school-aged children

OBJECTIVE

To determine the impact of varying attention-deficit/hyperactivity disorder (ADHD) diagnostic criteria, including new DSM-5 criteria, on prevalence estimates.

METHOD

Parent and teacher reports identified high- and low-screen children with ADHD from elementary schools in 2 states that produced a diverse overall sample. The parent interview stage included the Diagnostic Interview Schedule for Children-IV (DISC-IV), and up to 4 additional follow-up interviews. Weighted prevalence estimates, accounting for complex sampling, quantified the impact of varying ADHD criteria using baseline and the final follow-up interview data.

RESULTS

At baseline 1,060 caregivers were interviewed; 656 had at least 1 follow-up interview. Teachers and parents reported 6 or more ADHD symptoms for 20.5% (95% CI = 18.1%-23.2%) and 29.8% (CI = 24.5%-35.6%) of children respectively, with criteria for impairment and onset by age 7 years (DSM-IV) reducing these proportions to 16.3% (CI = 14.7%-18.0%) and 17.5% (CI = 13.3%-22.8%); requiring at least 4 teacher-reported symptoms reduced the parent-reported prevalence to 8.9% (CI = 7.4%-10.6%). Revising age of onset to 12 years per DSM-5 increased the 8.9% estimate to 11.3% (CI = 9.5%-13.3%), with a similar increase seen at follow-up: 8.2% with age 7 onset (CI = 5.9%-11.2%) versus 13.0% (CI = 7.6%-21.4%) with onset by age 12. Reducing the number of symptoms required for those aged 17 and older increased the overall estimate to 13.1% (CI = 7.7%-21.5%).

CONCLUSION

These findings quantify the impact on prevalence estimates of varying case definition criteria for ADHD. Further research of impairment ratings and data from multiple informants is required to better inform clinicians conducting diagnostic assessments. DSM-5 changes in age of onset and number of symptoms required for older adolescents appear to increase prevalence estimates, although the full impact is uncertain due to the age of our sample.

Adolescent exposure to cocaine, amphetamine, and methylphenidate cross-sensitizes adults to methamphetamine with drug- and sex-specific effects

The increasing availability, over-prescription, and misuse and abuse of ADHD psychostimulant medications in adolescent populations necessitates studies investigating the long-term effects of these drugs persisting into adulthood. Male and female C57Bl/6J mice were exposed to amphetamine (AMPH) (1.0 and 10 mg/kg), methylphenidate (MPD) (1.0 and 10 mg/kg), or cocaine (COC) (5.0 mg/kg) from postnatal day 22 to 31, which represents an early adolescent period. After an extended period of drug abstinence, adult mice were challenged with a subacute methamphetamine (METH) dose (0.5 mg/kg), to test the long-term effects of adolescent drug exposures on behavioral cross-sensitization using an open field chamber. There were no sex- or dose-specific effects on motor activity in adolescent, saline-treated controls. However, AMPH, MPD, and COC adolescent exposures induced cross-sensitization to a subacute METH dose in adulthood, which is a hallmark of addiction and a marker of long-lasting plastic changes in the brain. Of additional clinical importance, AMPH-exposed male mice demonstrated increased cross-sensitization to METH in contrast to the female-specific response observed in MPD-treated animals. There were no sex-specific effects after adolescent COC exposures. This study demonstrates differential drug, dose, and sex-specific alterations induced by early adolescent psychostimulant exposure, which leads to behavioral alterations that persist into adulthood.

Nonmedical stimulant use among young Asian-Americans, Native Hawaiians/Pacific Islanders, and mixed-race individuals aged 12-34 years in the United States

There are concerns over nonmedical use of prescription stimulants among youths, but little is known about the extent of use among young Asian-Americans, Native Hawaiians/Pacific Islanders (NHs/PIs), and mixed-race individuals-the fastest growing segments of the U.S. population. We examined prevalences and correlates of nonmedical stimulant use (NMSU) and disorder (StiUD) for these underrecognized groups. Whites were included as a comparison. Data were from young individuals aged 12-34 years in the 2005-2012 National Surveys on Drug Use and Health. We used logistic regression to estimate odds of past-year NMSU status. Significant yearly increases in lifetime NMSU prevalence were noted in Whites only. NHs/PIs (lifetime 7.33%, past-year 2.72%) and mixed-race individuals (10.20%, 2.82%) did not differ from Whites in NMSU prevalence (11.68%, 3.15%). Asian-Americans (lifetime 3.83%, past-year 0.90%) had lower prevalences than Whites. In each racial/ethnic group, "Methamphetamine/Desoxyn/Methedrine or Ritalin" was more commonly used than other stimulant groups; "got them from a friend/relative for free" and "bought them from a friends/relative" were among the most common sources. Females had greater odds than males of NMSU (among White, NH/PI, mixed-race individuals) and StiUD (among mixed-race individuals). Young adults (aged 18-25) had elevated odds of NMSU (White, NH/PI); adolescents had elevated odds of StiUD (White, mixed-race). Other substance use (especially marijuana, other prescription drugs) increased odds of NMSU and StiUD. NHs/PIs and mixed-race individuals were as likely as Whites to misuse stimulants. Research is needed to delineate health consequences of NMSU and inform prevention efforts for these understudied, rapidly-growing populations.

Frequent nonprescription stimulant use and risky behaviors in college students: the role of effortful control

OBJECTIVE

The goal of this study was to (a) investigate the association between nonprescription stimulant use (NPSU) and risky behaviors, including risky sex, driving, financial behaviors, and drug use and (b) collect preliminary evidence on mechanisms that may link NPSU to risky behaviors.

PARTICIPANTS

A sample of 555 college students was collected between August 2010 and February 2012.

METHODS

Students completed several self-report measures assessing their drug use history, attention-deficit and hyperactivity symptoms, temperament, and risky behaviors beyond drug use.

RESULTS

Those who reported more frequent NPSU were more likely to engage in high-risk behavior across all 4 domains studied. Further, effortful control abilities partially mediated the link between NPSU and risky behaviors.

CONCLUSIONS

These results highlight the associated risks of frequent NPSU for college students as well as provide future directions for examining effortful control as a potentially important mechanism linking NPSU to other risky behaviors.

PDE and cognitive processing: beyond the memory domain

Phosphodiesterase inhibitors (PDE-Is) enhance cAMP and/or cGMP signaling via reducing the degradation of these cyclic nucleotides. Both cAMP and cGMP signaling are essential for a variety of cellular functions and exert their effects both pre- and post-synaptically. Either of these second messengers relays and amplifies incoming signals at receptors on the cell surface making them important elements in signal transduction cascades and essential in cellular signaling in a variety of cell functions including neurotransmitter release and neuroprotection. Consequently, these processes can be influenced by PDE-Is as they increase cAMP and/or cGMP concentrations. PDE-Is have been considered as possible therapeutic agents to treat impaired memory function linked to several brain disorders, including depression, schizophrenia and Alzheimer's disease (AD). This review will, however, focus on the possible role of phosphodiesterases (PDEs) in cognitive decline beyond the memory domain. Here we will discuss the involvement of PDEs on three related domains: attention, information filtering (sensory- and sensorimotor gating) and response inhibition (drug-induced hyperlocomotion). Currently, these are emerging cognitive domains in the field of PDE research. Here we discuss experimental studies and the potential beneficial effects of PDE-I drugs on these cognitive domains, as effects of PDE-Is on these domains could potentially influence effects on memory performance. Overall, PDE4 seems to be the most promising target for all domains discussed in this review.

Associations of sleep disturbance with ADHD: implications for treatment

Attention-deficit/hyperactivity disorder (ADHD) is commonly associated with disordered or disturbed sleep. The relationships of ADHD with sleep problems, psychiatric comorbidities and medications are complex and multidirectional. Evidence from published studies comparing sleep in individuals with ADHD with typically developing controls is most concordant for associations of ADHD with: hypopnea/apnea and peripheral limb movements in sleep or nocturnal motricity in polysomnographic studies; increased sleep onset latency and shorter sleep time in actigraphic studies; and bedtime resistance, difficulty with morning awakenings, sleep onset difficulties, sleep-disordered breathing, night awakenings and daytime sleepiness in subjective studies. ADHD is also frequently coincident with sleep disorders (obstructive sleep apnea, peripheral limb movement disorder, restless legs syndrome and circadian-rhythm sleep disorders). Psychostimulant medications are associated with disrupted or disturbed sleep, but also ‘paradoxically’ calm some patients with ADHD for sleep by alleviating their symptoms. Long-acting formulations may have insufficient duration of action, leading to symptom rebound at bedtime. Current guidelines recommend assessment of sleep disturbance during evaluation of ADHD, and before initiation of pharmacotherapy, with healthy sleep practices the first-line option for addressing sleep problems. This review aims to provide a comprehensive overview of the relationships between ADHD and sleep, and presents a conceptual model of the modes of interaction: ADHD may cause sleep problems as an intrinsic feature of the disorder; sleep problems may cause or mimic ADHD; ADHD and sleep problems may interact, with reciprocal causation and possible involvement of comorbidity; and ADHD and sleep problems may share a common underlying neurological etiology.

Cognitive effects of methylphenidate in healthy volunteers: a review of single dose studies

Methylphenidate (MPH), a stimulant drug with dopamine and noradrenaline reuptake inhibition properties, is mainly prescribed in attention deficit hyperactivity disorder, is increasingly used by the general population, intending to enhance their cognitive function. In this literature review, we aim to answer whether this is effective. We present a novel way to determine the extent to which MPH enhances cognitive performance in a certain domain. Namely, we quantify this by a percentage that reflects the number of studies showing performance enhancing effects of MPH. To evaluate whether the dose-response relationship follows an inverted-U-shaped curve, MPH effects on cognition are also quantified for low, medium and high doses, respectively. The studies reviewed here show that single doses of MPH improve cognitive performance in the healthy population in the domains of working memory (65% of included studies) and speed of processing (48%), and to a lesser extent may also improve verbal learning and memory (31%), attention and vigilance (29%) and reasoning and problem solving (18%), but does not have an effect on visual learning and memory. MPH effects are dose-dependent and the dose-response relationship differs between cognitive domains. MPH use is associated with side effects and other adverse consequences, such as potential abuse. Future studies should focus on MPH specifically to adequately asses its benefits in relation to the risks specific to this drug.

Using structural equation modeling to understand prescription stimulant misuse: a test of the Theory of Triadic Influence

OBJECTIVE

To test a theory-driven model of health behavior to predict the illicit use of prescription stimulants (IUPS) among college students.

PARTICIPANTS

A probability sample of 554 students from one university located in California (response rate=90.52%).

METHODS

Students completed a paper-based survey developed with guidance from the Theory of Triadic Influence. We first assessed normality of measures and checked for multicollinearity. A single structural equation model of frequency of IUPS in college was then tested using constructs from the theory's three streams of influence (i.e., intrapersonal, social situation/context, and sociocultural environment) and four levels of causation (i.e., ultimate causes, distal influences, proximal predictors, and immediate precursors).

RESULTS

Approximately 18% of students reported engaging in IUPS during college, with frequency of use ranging from never to 40 or more times per academic term. The model tested had strong fit and the majority of paths specified within and across streams were significant at the p<0.01 level. Additionally, 46% of the variance in IUPS frequency was explained by the tested model.

CONCLUSIONS

Results suggest the utility of the TTI as an integrative model of health behavior, specifically in predicting IUPS, and provide insight on the need for multifaceted prevention and intervention efforts.

Adolescent athletic participation and nonmedical Adderall use: an exploratory analysis of a performance-enhancing drug

OBJECTIVE

A primary motive for adolescents and young adults to nonmedically use prescription stimulants is to help them study. Adolescents and young adults are using prescription stimulants, such as Adderall (amphetamine aspartate, amphetamine sulfate, dextroamphetamine saccharate, dextroamphetamine sulfate), as performance enhancers in certain social domains, including academics and sports. The purpose of this exploratory study was to examine the nonmedical use of Adderall (a commonly prescribed stimulant used nonmedically) among adolescents who participate in competitive sports.

METHOD

The Monitoring the Future survey for 2010 and 2011, a representative sample of 8th- and 10th-grade students, surveyed involvement in competitive sports and nonmedical Adderall use among 21,137 adolescents. Past-year nonmedical use of Adderall served as the main outcome measure. Logistic regression analyses were run to examine whether sports participation in general and involvement in different types of competitive sports participation were associated with past-year nonmedical use of Adderall among males and females.

RESULTS

The odds of past-year nonmedical use of Adderall among males were higher for male respondents who participated in lacrosse (adjusted odds ratio [AOR] = 2.52, 95% CI [1.20, 5.29]) and wrestling (AOR = 1.74, 95% CI [1.01, 2.98]). However, no particular sport among females was found to be associated with past-year nonmedical use of Adderall.

CONCLUSIONS

Certain extracurricular activities, such as high-contact sports, may influence male participants to misuse prescription stimulants as performance enhancers either on or off the playing field.

Long-term oral methylphenidate treatment in adolescent and adult rats: differential effects on brain morphology and function

Methylphenidate is a widely prescribed psychostimulant for treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents, which raises questions regarding its potential interference with the developing brain. In the present study, we investigated effects of 3 weeks oral methylphenidate (5 mg/kg) vs vehicle treatment on brain structure and function in adolescent (post-natal day [P]25) and adult (P65) rats. Following a 1-week washout period, we used multimodal magnetic resonance imaging (MRI) to assess effects of age and treatment on independent component analysis-based functional connectivity (resting-state functional MRI), D-amphetamine-induced neural activation responses (pharmacological MRI), gray and white matter tissue volumes and cortical thickness (postmortem structural MRI), and white matter structural integrity (postmortem diffusion tensor imaging (DTI)). Many age-related differences were found, including cortical thinning, white matter development, larger dopamine-mediated activation responses and increased striatal functional connectivity. Methylphenidate reduced anterior cingulate cortical network strength in both adolescents and adults. In contrast to clinical observations from ADHD patient studies, methylphenidate did not increase white matter tissue volume or cortical thickness in rat. Nevertheless, DTI-based fractional anisotropy was higher in the anterior part of the corpus callosum following adolescent treatment. Furthermore, methylphenidate differentially affected adolescents and adults as evidenced by reduced striatal volume and myelination upon adolescent treatment, although we did not observe adverse treatment effects on striatal functional activity. Our findings of small but significant age-dependent effects of psychostimulant treatment in the striatum of healthy rats highlights the importance of further research in children and adolescents that are exposed to methylphenidate.

Attention-deficit/hyperactivity disorder in postsecondary students

A PubMed review was conducted for papers reporting on attention-deficit/hyperactivity disorder (ADHD) in postsecondary students. The review was performed in order to determine the prevalence and symptomatology of ADHD in postsecondary students, to examine its effects on academic achievement, and discuss appropriate management. The prevalence of ADHD symptoms among postsecondary students ranges from 2% to 12%. Students with ADHD have lower grade point averages and are more likely to withdraw from courses, to indulge in risky behaviors, and to have other psychiatric comorbidities than their non-ADHD peers. Ensuring that students with ADHD receive appropriate support requires documented evidence of impairment to academic and day-to-day functioning. In adults with ADHD, stimulants improve concentration and attention, although improved academic productivity remains to be demonstrated. ADHD negatively impacts academic performance in students and increases the likelihood of drug and alcohol problems. Affected students may therefore benefit from disability support services, academic accommodations, and pharmacological treatment.

Prescription stimulants are "a okay": applying neutralization theory to college students' nonmedical prescription stimulant use

OBJECTIVE

National college health data indicate that prescription stimulants are the most widely misused prescription drugs among college students, with 9% admitting to nonmedical use within the past year.(1) Although motivations for the nonmedical use of these drugs have been explored, scant attention has been paid to justifications for nonmedical use. This article fills that gap by expounding upon the justifications students incite to defend their nonmedical use of these drugs.

PARTICIPANTS

Seventy-six college students from a large, public northwestern university.

METHODS

Semistructured interviews were conducted during the 2010-2011 academic year.

RESULTS

Inductive analysis uncovered social learning theories of crime/deviance, more specifically, Sykes and Matza's neutralization theory(2) as helping to inform justifications for nonmedical stimulant use. This theory was modified to better encompass the justifications that students employed.

CONCLUSION

Justifications for use must become a more central part of the conversation surrounding nonmedical stimulant use among the college population.