Modafinil improves symptoms of attention-deficit/hyperactivity disorder across subtypes in children and adolescents

Pediatric attention deficit hyperactivity disorder (ADHD): 2022 updates on pharmacological management

INTRODUCTION

Pediatric attention-deficit disorder (ADHD) impacts a significant percentage of the population world-wide. Pharmacologic treatments have been shown to be safe and effective for managing symptoms. Various medication formulations exist, and new medication agents are continually approved each year.

AREAS COVERED

This article offers an overview of ADHD, an overview of both stimulant and non-stimulant medication options as well as an overview of stimulant misuse. It explores the medication mechanisms of action and side effect profiles, as well as offering an in-depth summary of the novel agents recently approved and soon-to-be approved for use in youth. PubMed and Medline were utilized. Search terms included children, adolescents, ADHD, and medication. FDA package inserts were reviewed for all medications.

EXPERT OPINION

New formulations of medications include an evening administered, extended, and delayed-release form of methylphenidate (DR/ER MPH), a methylphenidate pro-drug (serdexmethylphenidate) and an amphetamine patch. The availability of a new SNRI (selective norepinephrine reuptake inhibitor), viloxazine extended-release (VER), and the pending approval of a triple reuptake inhibitor (centanafadine) provides welcome additions to the prescriber's toolbox.

Modafinil reduces choice impulsivity while increasing motor activity in preadolescent rats treated prenatally with alcohol

Rats exposed prenatally to alcohol show a reduction in the spontaneous activity of dopaminergic neurons of the ventral tegmental area (VTA), as well as greater impulsive behavior and motor activity, behavioral alterations that have been related to dopaminergic dysfunction. Modafinil (MOD) is a dopamine (DA) reuptake blocker prescribed to treat sleep disorders; however, in recent years it has been used for the treatment of ADHD with positive results. Also, studies in humans and rodents show beneficial effects on learning and attention; however, studies evaluating MOD effects on impulsivity are few and show contradictory results. The purpose of this work was to evaluate the effect of a daily dose of MOD (60 mg/kg i.g.) on cognitive (or choice) impulsivity and motor activity in male preadolescent rats exposed prenatally to alcohol or sucrose (isocaloric control). MOD reduced the impulsive responses in a delay discounting task (DDT) at the same time that increased the motor activity, in both healthy and prenatal alcohol treated rats; however, MOD reduced the response latency in DDT only in prenatal alcohol treated rats. This differential effect of DA activation on impulsivity and motor activity show that the MOD dose that improves the impulse control, does not necessarily decrease motor activity, and suggests a possible differential neural mechanism underlying the expression of these behaviors. On the other hand, the changes in the response latency, only in prenatal alcohol treated groups, suggest that decision-making in animals with a dopaminergic dysfunction is more susceptible to be affected by MOD action.

Social cognition

Social cognition is a major problem underlying deficiencies in interpersonal relationships in several psychiatric populations. And yet there is currently no gold standard for pharmacological treatment of psychiatric illness that directly targets these social cognitive areas. This chapter serves to illustrate some of the most innovative attempts at pharmacological modulation of social cognition in psychiatric illnesses including schizophrenia, borderline personality disorder, autism spectrum disorders, antisocial personality disorder and psychopathy, social anxiety disorder, and posttraumatic stress disorder. Pharmacological modulation includes studies administering oxytocin, ecstasy (MDMA), modafinil, methylphenidate, and D-cycloserine. Furthermore, some background on social cognition research in healthy individuals, which could be helpful in developing future treatments, is provided as well as the potential for each drug as a long-term treatment option.

Developing interventions for cancer-related cognitive dysfunction in childhood cancer survivors

Survivors of childhood cancer frequently experience cancer-related cognitive dysfunction, commonly months to years after treatment for pediatric brain tumors, acute lymphoblastic leukemia (ALL), or tumors involving the head and neck. Risk factors for cancer-related cognitive dysfunction include young age at diagnosis, treatment with cranial irradiation, use of parenteral or intrathecal methotrexate, female sex, and pre-existing comorbidities. Limiting use and reducing doses and volume of cranial irradiation while intensifying chemotherapy have improved survival and reduced the severity of cognitive dysfunction, especially in leukemia. Nonetheless, problems in core functional domains of attention, processing speed, working memory and visual-motor integration continue to compromise quality of life and performance. We review the epidemiology, pathophysiology and assessment of cancer-related cognitive dysfunction, the impact of treatment changes for prevention, and the broad strategies for educational and pharmacological interventions to remediate established cognitive dysfunction following childhood cancer. The increased years of life saved after childhood cancer warrants continued study toward the prevention and remediation of cancer-related cognitive dysfunction, using uniform assessments anchored in functional outcomes.

The use of stimulant medications for non-core aspects of ADHD and in other disorders

Psychostimulants play a central role in the management of ADHD. Here we review the evidence pertaining to the use of methylphenidate, dexamphetamine and related amphetamine salts, the prodrug lisdexamfetamine and modafinil for the management of comorbid ADHD and non-ADHD indications. There is a growing consensus that stimulant medications are helpful at improving the emotional dysregulation and lability, and oppositional and conduct symptoms that are often associated with ADHD. There is some evidence that psychostimulants may improve outcomes in those with treatment resistant depression, reduce negative symptoms and improve cognitive performance in schizophrenia, and that methylphenidate may reduce binge eating in those with bulimia nervosa. In general medicine, whilst the evidence is at times contradictory, psychostimulants have been shown in some studies to be effective treatments for chronic fatigue and narcolepsy, and to improve outcomes post stroke, post head injury, in dementia and various cancers. It seems likely that these effects often result from a combination of, reduction in fatigue, improvements in concentration and cognitive functioning and a lifting of mood which may be a direct or indirect consequence of the medication. Further studies seem warranted and these should focus on efficacy, effectiveness and long term safety. This article is part of the Special Issue entitled 'CNS Stimulants'.

A 9-week, randomized, double-blind, placebo-controlled, parallel-group, dose-finding study to evaluate the efficacy and safety of modafinil as treatment for adults with ADHD

OBJECTIVE

This study evaluated the efficacy and tolerability of modafinil at a range of doses, versus placebo, in alleviating symptoms of ADHD in adults.

METHOD

Adult patients with ADHD were randomized in 1:1:1:1:1 fashion to double-blind treatment with modafinil 255, 340, 425, or 510 mg daily or placebo for 9 weeks. The primary efficacy outcome was the change from baseline at final visit in the Adult ADHD Investigator Symptom Rating Scale (AISRS) total score.

RESULTS

A total of 338 patients were enrolled, of whom 330 received at least 1 dose of study medication (modafinil or placebo). No statistically significant difference in the AISRS total score was observed at final visit between any modafinil group and placebo; however, some observations among patients who completed the trial may warrant further investigation.

CONCLUSION

Modafinil was reasonably tolerated but did not demonstrate a benefit on ADHD symptoms in adults.

Electroencephalogram effects of armodafinil: comparison with behavioral alertness

Development of central nervous system-acting drugs would be enhanced by suitable biomarkers that reflect the targeted pathophysiologic brain state. The electroencephalogram (EEG) has several characteristics of an ideal biomarker and can be promptly adapted to pre-clinical and clinical testing. The aim of this study was to evaluate EEG as a measure of the wakefulness-promoting effect of armodafinil in sleep deprived healthy subjects. Armodafinil pharmacodynamics were simultaneously assessed by EEG- and behavioral-based measures including a well-established measure of alertness. Using two quantitative EEG-based measures-power spectral and event-related brain activity analyses-we observed that armodafinil mitigated the slowing of brain activity and the decrease of the event-related brain activity caused by sleep deprivation. Armodafinil-induced changes in EEG are in agreement and explain up to 73.1% of the armodafinil-induced changes in alertness. Our findings suggest that EEG can serve as a marker of the wakefulness-promoting drug effect.

Overdose of drugs for attention-deficit hyperactivity disorder: clinical presentation, mechanisms of toxicity, and management

The prevalence of attention-deficit hyperactivity disorder (ADHD) in the USA is estimated at approximately 4-9% in children and 4% in adults. It is estimated that prescriptions for ADHD medications are written for more than 2.7 million children per year. In 2010, US poison centers reported 17,000 human exposures to ADHD medications, with 80% occurring in children <19 years old and 20% in adults. The drugs used for the treatment of ADHD are diverse but can be roughly separated into two groups: the stimulants such as amphetamine, methylphenidate, and modafinil; and the non-stimulants such as atomoxetine, guanfacine, and clonidine. This review focuses on mechanisms of toxicity after overdose with ADHD medications, clinical effects from overdose, and management. Amphetamine, dextroamphetamine, and methylphenidate act as substrates for the cellular monoamine transporter, especially the dopamine transporter (DAT) and less so the norepinephrine (NET) and serotonin transporter. The mechanism of toxicity is primarily related to excessive extracellular dopamine, norepinephrine, and serotonin. The primary clinical syndrome involves prominent neurological and cardiovascular effects, but secondary complications can involve renal, muscle, pulmonary, and gastrointestinal (GI) effects. In overdose, the patient may present with mydriasis, tremor, agitation, hyperreflexia, combative behavior, confusion, hallucinations, delirium, anxiety, paranoia, movement disorders, and seizures. The management of amphetamine, dextroamphetamine, and methylphenidate overdose is largely supportive, with a focus on interruption of the sympathomimetic syndrome with judicious use of benzodiazepines. In cases where agitation, delirium, and movement disorders are unresponsive to benzodiazepines, second-line therapies include antipsychotics such as ziprasidone or haloperidol, central alpha-adrenoreceptor agonists such as dexmedetomidine, or propofol. Modafinil is not US FDA approved for treatment of ADHD; however, it has been shown to improve ADHD signs and symptoms and has been used as an off-label pharmaceutical for this diagnosis in both adults and children. The mechanism of action of modafinil is complex and not fully understood. It is known to cause an increase in extracellular concentrations of dopamine, norepinephrine, and serotonin in the neocortex. Overdose with modafinil is generally of moderate severity, with reported ingestions of doses up to 8 g. The most common neurological effects include increased anxiety, agitation, headache, dizziness, insomnia, tremors, and dystonia. The management of modafinil overdose is largely supportive, with a focus on sedation, and control of dyskinesias and blood pressure. Atomoxetine is a selective presynaptic norepinephrine transporter inhibitor. The clinical presentation after overdose with atomoxetine has generally been mild. The primary effects have been drowsiness, agitation, hyperactivity, GI upset, tremor, hyperreflexia, tachycardia hypertension, and seizure. The management of atomoxetine overdose is largely supportive, with a focus on sedation, and control of dyskinesias and seizures. Clonidine is a synthetic imidazole derivative with both central and peripheral alpha-adrenergic agonist actions. The primary clinical syndrome involves prominent neurological and cardiovascular effects, with the most commonly reported features of depressed sensorium, bradycardia, and hypotension. While clonidine is an anti-hypertensive medication, a paradoxical hypertension may occur early with overdose. The clinical syndrome after overdose of guanfacine may be mixed depending on central or peripheral alpha-adrenoreceptor effects. Initial clinical effects may be drowsiness, lethargy, dry mouth, and diaphoresis. Cardiovascular effects may depend on time post-ingestion and may present as hypotension or hypertension. The management of guanfacine overdose is largely supportive, with a focus on support of blood pressure. Overdose with ADHD medications can produce major morbidity, with many cases requiring intensive care medicine and prolonged hospital stays. However, fatalities are rare with appropriate care.

Pharmacological treatment of attention deficit hyperactivity disorder in children and adolescents: clinical strategies

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder of childhood that can result in significant functional impairment, and if not adequately treated can lead to impaired quality of life. Pharmacotherapy is considered the first-line treatment for ADHD in children and adolescents. We review both recent literature and seminal studies regarding the pharmacological treatment of ADHD in children and adolescents. There is ample evidence for the efficacy and safety of both stimulants and non-stimulants in the treatment of ADHD. We review important aspects of evaluation and assessment and discuss first-line pharmacological treatments and as well as when to consider using alternative pharmacological agents. Treatment approaches to manage frequently seen comorbid disorders with ADHD are also covered.

Current treatment of selected pediatric sleep disorders

While pediatric sleep disorders are relatively common, treatments are often not straightforward. There is often a paucity of gold standard studies and data available to guide clinicians, treatments may yield arguably incomplete results, interventions may require chronic use, and/ or involve multiple modalities including behavioral interventions that require high parental and family commitment. This review points out diagnostic differences compared to adults and focuses on current therapy for selected common pediatric sleep disorders including sleep disordered breathing/ obstructive sleep apnea, narcolepsy, and restless legs syndrome. Other common pediatric sleep disorders, such as insomnia and parasomnias, are not covered.

Modafinil effects on cognition and emotion in schizophrenia and its neurochemical modulation in the brain

Modafinil is a central nervous system wake promoting agent used for the treatment of excessive daytime sleeping. Its vigilance promoting properties and low abuse potential has intrigued the scientific community and has led to use it as a cognitive enhancer, before its neural functions were understood. Here, we review the effects of modafinil in human cognition and emotion and its specific actions on symptoms in patients with schizophrenia and whether these are consistently effective throughout the literature. We also performed a systematic review on the effects of modafinil on neurotransmitter signalling in different areas of the brain in order to better understand the neuromechanisms of its cognitive and emotional enhancing properties. A review of its effects in schizophrenia suggests that modafinil facilitates cognitive functions, with pro-mnemonic effects and problem solving improvements. Emotional processing also appears to be enhanced by the drug, although to date there are only a limited number of studies. The systematic review on the neurochemical modulation of the modafinil suggests that its mnemonic enhancing properties might be the result of glutamatergic and dopaminergic increased neuronal activation in the hippocampus and in the prefrontal cortex respectively. Other neurotransmitters were also activated by modafinil in various limbic brain areas, suggesting that the drug acts on these brain regions to influence emotional responses. These reviews seek to delineate the neuronal mechanisms by which modafinil affects cognitive and emotional function. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Examining the association between stimulant treatment and cognitive outcomes across the life cycle of adults with attention-deficit/hyperactivity disorder: a controlled cross-sectional study

Few studies have evaluated the effects of stimulants on cognition in adults with attention-deficit/hyperactivity disorder (ADHD). We evaluated the impact of stimulant treatment on neurocognition in a cross-sectional sample of adults with ADHD. Comparisons were made between adults with ADHD who received (n = 105) and who had never received pharmacotherapy (n = 116) and 146 controls. The subjects were assessed cross-sectionally using a structured diagnostic interview and a neurocognitive battery. We modeled cognitive measures as a function of age and group status using linear regression. Treated ADHD subjects had statistically significantly better scores on measures of IQ than did untreated ones. The treated group also had better (not statistically significant) scores on neuropsychological measures. The direction of the effects of stimulant on neurocognition suggests that either good cognitive functioning may be a determinant of seeking treatment or that stimulant treatment may improve cognition in adults with ADHD. However, this does not indicate a clear causal relationship.

Divergence by ADHD subtype in smoking cessation response to OROS-methylphenidate

INTRODUCTION

Attention deficit hyperactivity disorder (ADHD) is a neuropsychiatric condition subclassified in DSM-IV according to its core symptoms domains as (a) predominantly inattentive (ADHD-IN), (b) predominantly hyperactive/impulsive (ADHD-H), and (c) combined inattentive and hyperactive/impulsive (ADHD-C). Whether these subtypes represent distinct clinical entities or points on a severity continuum is controversial. Divergence in treatment response is a potential indicator of qualitative heterogeneity. This study examined smoking cessation response by ADHD subtype to osmotic-release oral system methylphenidate (OROS-MPH).

METHODS

Male and female adult smokers (ADHD-C = 167 and ADHD-IN = 87) were randomized to receive OROS-MPH or placebo as augmentation treatment to nicotine patch and counseling. Logistic regression was conducted to test the effect of OROS-MPH versus placebo on prolonged smoking abstinence by ADHD subtype.

RESULTS

The subtypes were similar in baseline demographic, smoking, and psychiatric history but differed in smoking cessation response to OROS-MPH or placebo as a function of nicotine dependence level. The 3-way interaction was significant; χ(2)(1) = 8.22, p < .01. Among highly dependent smokers, the prolonged abstinence rates were greater with OROS-MPH than with placebo in the ADHD-C group (60% vs. 31.3%, respectively, p < .05) but higher with placebo than with OROS-MPH in the ADHD-IN group (60% vs. 11.8%, respectively, p < .01). Abstinence rates did not differ by subtype or treatment among smokers who were less nicotine dependent.

CONCLUSION

Contrasting treatment response and divergence in the impact of nicotine dependence level support the hypothesis of ADHD subtypes as distinct clinical entities and may indicate the need and directions for personalized targeted treatments of smokers with ADHD.

Use of ADHD drugs in the Nordic countries: a population-based comparison study

OBJECTIVE

To compare national use of attention-deficit/hyperactivity disorder (ADHD) drugs between five Nordic countries.

METHOD

A population-based drug utilisation study based on nationwide prescription databases, covering in total 24 919 145 individuals in 2007. ADHD drugs defined according to the World Health Organization Anatomic Therapeutic Chemical classification system as centrally acting sympathomimetics (N06BA).

RESULTS

The 2007 prevalence of ADHD drug use among the total Nordic population was 2.76 per 1000 inhabitants, varying from 1.23 per 1000 in Finland to 12.46 per 1000 in Iceland. Adjusting for age, Icelanders were nearly five times more likely than Swedes to have used ADHD drugs (Prev.Ratio = 4.53, 95% CI: 4.38-4.69). Prevalence among boys (age 7-15) was fourfold the prevalence among girls (Prev.Ratio = 4.28, 95% CI: 3.70-4.96). The gender ratio was diminished among adults (age 21 +) (Prev.Ratio = 1.24, CI: 1.21-1.27).

CONCLUSION

A considerable national variation in use of ADHD drugs exists between the Nordic countries.

Sleep problems in the child with attention-deficit hyperactivity disorder: defining aetiology and appropriate treatments

An estimated 25-50% of children and adolescents with attention-deficit hyperactivity disorder (ADHD) experience problems with sleep. The most common sleep problems reported in children with ADHD include delayed sleep onset, sleep or bedtime resistance, prolonged tiredness upon waking and daytime sleepiness. Higher incidences of sleep disorders such as restless legs syndrome, periodic limb movement disorder and sleep-disordered breathing have been reported in paediatric ADHD populations compared with control populations. In some cases, medications for ADHD and/or co-morbid disorders may also contribute to sleep disturbances. Assessment tools, such as parent-child questionnaires and sleep diaries, can help clinicians evaluate sleep disturbances. Sleep problems may potentially exacerbate ADHD symptoms, and interventions targeted at ensuring adequate sleep (including behavioural, dietary, specific pharmacological agents for treatment-induced insomnia, and melatonin) could in turn potentially attenuate symptoms associated with ADHD, such as irritability. Whether metabolic or neurological pathways common to both sleep and ADHD may be disrupted, and whether targeting treatments to these pathways may simultaneously improve both ADHD and sleep symptoms, needs further elucidation.

Understanding attention-deficit/hyperactivity disorder from childhood to adulthood

Attention deficit/hyperactivity disorder (ADHD) is among the most common neurobehavioral disorders requiring treatment in children and adolescents. The disorder is often chronic, with prominent symptoms and impairment spanning into adulthood. It is often associated with co-occurring disorders, including disruptive, mood, anxiety, and substance abuse disorders. The diagnosis of ADHD is clinically established by review of symptoms and impairment. The biological underpinning of the disorder is supported by genetic, neuroimaging, neurochemistry, and neuropsychological data. All aspects of an individual's life need to be considered in the diagnosis and treatment of ADHD. Multimodal treatment includes educational, family, and individual support. Psychotherapy alone and in combination with medication is helpful for treating patients with ADHD and comorbid disorders. Pharmacotherapy, including stimulants, noradrenergic agents, α-agonists, and antidepressants, plays a fundamental role in the long-term management of ADHD.

Psychostimulant-like discriminative stimulus and locomotor sensitization properties of the wake-promoting agent modafinil in rodents

The present studies assessed the potential abuse liability and likely mechanism(s) of action of the wake-promoting agent modafinil.

METHODS

Experiments assessed the locomotor sensitization (LS) and discriminative stimulus (DS) properties of modafinil in mouse and rat, respectively. Comparative data were generated with a range of psychostimulants and monoamine reuptake inhibitors.

RESULTS

Repeated administration of d-amphetamine and cocaine, psychostimulants with high abuse liability, resulted in the induction and expression of LS in mice. Bupropion and caffeine, two psychostimulants not abused in humans, were not associated with LS. GBR12909 induced LS during repeated exposure, but there was no evidence of expression of LS after acute challenge following withdrawal. In contrast, repeated administration of modafinil resulted in the expression, but not induction, of LS. d-amphetamine, but not the mu-opioid agonist morphine or the nAChR agonist nicotine, fully substituted for the cocaine DS in rats. The selective dopamine transporter (DAT) inhibitor GBR12909 fully substituted, the preferential norepinephrine transporter (NET) inhibitor desipramine partially substituted, and the selective serotonin reuptake inhibitor citalopram failed to substitute for cocaine. Modafinil fully substituted for cocaine, similar to the mixed DAT/NET inhibitor bupropion.

CONCLUSIONS

Two preclinical assays indicated potential abuse liability of modafinil; drug discrimination studies suggest DAT blockade by modafinil is a likely mechanism of action in vivo.

Issues in the management of patients with complex attention-deficit hyperactivity disorder symptoms

Patients with attention-deficit hyperactivity disorder (ADHD) exhibit a wide range of symptoms related to functional impairment. Psychiatric comorbidities are highly prevalent among these patients, often emerging at an early age and persisting (or reoccurring) into adulthood. Among the most common types of comorbidities in children and adults are disruptive behaviour disorders such as oppositional defiant disorder and conduct disorder, mood disorders, anxiety disorders, and substance use disorders. The heterogeneous clinical presentation of ADHD, which also changes with maturation into adulthood, may often obscure the presence of psychiatric comorbidity. Co-occurring disorders frequently go undetected and lead to negative effects on psychosocial and long-term functional outcomes. As with uncomplicated ADHD, medication therapy combined with psychosocial interventions may be necessary. With comorbid disorders, two or more medications may be considered to appropriately manage both ADHD and the comorbid disorder. However, there are few studies that discuss combination medication treatments and there are no current US FDA-approved combined treatments for ADHD and comorbid conditions. This raises significant challenges and risks for poor tolerability and drug-drug interactions. Nevertheless, identification and appropriate treatment must be given a high priority for these highly vulnerable patients to derive optimal benefits from treatment.

Psychopharmacology of ADHD in pediatrics: current advances and issues

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral developmental disorder found in 3% to 8% of children and adolescents. An important part of ADHD management is psychopharmacology, which includes stimulants, norepinephrine reuptake inhibitors, alpha-2 agonists, and antidepressants. Medications with the best evidence-based support for ADHD management are the stimulants methylphenidate and amphetamine. A number of newer, long-acting stimulants are now available and a number of new medications are considered that are under current research.