The female side of pharmacotherapy for ADHD-A systematic literature review

Differential phase-amplitude coupling in nucleus accumbens and orbitofrontal cortex reflects decision-making during a delay discounting task

BACKGROUND

The impulsive choice is characterized by the preference for a small immediate reward over a bigger delayed one. The mechanisms underlying impulsive choices are linked to the activity in the Nucleus Accumbens (NAc), the orbitofrontal cortex (OFC), and the dorsolateral striatum (DLS). While the study of functional connectivity between brain areas has been key to understanding a variety of cognitive processes, it remains unclear whether functional connectivity differentiates impulsive-control decisions.

METHODS

To study the functional connectivity both between and within NAc, OFC, and DLS during a delay discounting task, we concurrently recorded local field potential in NAc, OFC, and DLS in rats. We then quantified the degree of phase-amplitude coupling (PAC), coherence, and Granger Causality between oscillatory activities in animals exhibiting either a high (HI) or low (LI) tendency for impulsive choices.

RESULTS

Our results showed a differential pattern of PAC during decision-making in OFC and NAc, but not in DLS. While theta-gamma PAC in OFC was associated with self-control decisions, a higher delta-gamma PAC in both OFC and NAc biased decisions toward impulsive choices in both HI and LI groups. Furthermore, during the reward event, Granger Causality analysis indicated a stronger NAc➔OFC gamma contribution in the HI group, while the LI group showed a higher OFC➔NAc gamma contribution.

CONCLUSIONS

The overactivity in NAc during reward in the HI group suggests that exacerbated contribution of NAcCore can lead to an overvaluation of reward that biases the behavior toward the impulsive choice.

Assessing adherence and clinical utility of modified goal management training for adolescents with ADHD: A pilot study

Many adolescents with attention-deficit hyperactivity disorder (ADHD) have executive functioning (EF) difficulties that contribute to academic and social-emotional challenges. This pilot explored adherence to and effectiveness of modified Goal Management Training (GMT), an EF intervention, with ADHD youth. Six adolescents with ADHD (14-17 years, 2 female) participated in a 6-session online group. Adherence was tracked via attendance and homework. Reliable change scores gaged pre-post differences on measures before and after training (primary: everyday EF and goal attainment; secondary: EF task performance, functional impairment, emotional adjustment, and self-concept). All youth attended at least 4 sessions, though homework completion was mixed. Four youth achieved their goal, some demonstrated reliable change on outcome measures, and all evidenced a reduction in impairment. Results support the feasibility of modified GMT in adolescents with ADHD and suggest that youth may benefit from this more personalized and holistic approach to EF intervention.

Comorbid Attention Deficit Hyperactivity Disorder in Women with Premenstrual Dysphoric Disorder

Background: This study evaluated the associations between inattention, impulsivity, and attention deficit hyperactivity disorder (ADHD) in women with premenstrual dysphoric disorder (PMDD) across the menstrual cycle. Methods: This study enrolled 58 women with PMDD and 50 controls. Symptoms were assessed using the Attention and Performance Self-Assessment Scale and the Dickman Impulsivity Inventory during the pre-ovulatory (PO), mid-luteal (ML), and late luteal (LL) phases of the menstrual cycle. Results: The chi-square analysis revealed a significant association between ADHD and PMDD. Women with PMDD experienced a greater increase in scores of prospective everyday memory problems and difficulties maintaining focused attention from the PO phase to LL phase than the controls; in addition, they had higher scores in dysfunctional impulsivity during the LL phase than the controls. Among women in the PMDD group, those with ADHD had higher scores in prospective everyday memory problems and dysfunctional impulsivity during the PO and ML phases than those without ADHD. Women in the PMDD group without ADHD had a greater increase in scores of prospective everyday memory problems, difficulties maintaining focused attention, and dysfunctional impulsivity from the PO phase to the LL phase than the controls. Conclusion: Our study demonstrated that women with PMDD were more likely to have comorbid ADHD and higher levels of inattention across the menstrual cycle. PMDD was associated with increased impulsivity during the LL phase, independent of ADHD, but it was not associated with a persistent elevation of impulsivity. Furthermore, PMDD women with comorbid ADHD experienced higher inattention and impulsivity during the PO and ML phases than those without it. Thus, ADHD comorbidity should be assessed when assessing or intervening in the symptoms of inattention and impulsivity in women with PMDD.

Secondary analyses of sex differences in attention improvements across three clinical trials of a digital therapeutic in children, adolescents, and adults with ADHD

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) remains underdiagnosed and undertreated in girls. Inattentive symptoms, often predominant in girls with ADHD, represent a key driver of impairment and often persist into adulthood. AKL-T01 is a regulated digital therapeutic targeting inattention. We examined potential sex differences in the efficacy of AKL-T01 in three separate trials for 1) children, 2) adolescents, and 3) adults.

METHODS

We conducted secondary analyses of clinical outcomes by sex in three AKL-T01 randomized clinical trials in ADHD (n1 = 180 children 30.6% female, M(SD) age = 9.71 (1.32); n2 = 146 adolescents; 41.1% female, M(SD) age = 14.34 (1.26); n3 = 153 adults; 69.9% female, M(SD) age = 39.86 (12.84)). Active treatment participants used AKL-T01 for 25 min/day over 4-6 weeks. Primary outcomes included change in attention on the Test of Variables of Attention (TOVA) and symptom change on the clinician-rated ADHD Rating Scale (ADHD-RS). To evaluate study hypotheses, we conducted a series of robust linear regressions of TOVA and ADHD-RS change scores by sex, adjusting for baseline scores.

RESULTS

In children, girls demonstrated greater improvement in objective attention relative to boys following AKL-T01 (TOVA Attentional Composite Score; Cohen's d = .36 and Reaction Time Mean Half; Cohen's d = .54), but no significant sex differences in ADHD rating scale change. We did not observe significant sex differences in outcomes in the adolescent or adult trials. Limitations include binary sex categorization and slight study design variation across the three samples.

CONCLUSION

AKL-T01 might notably improve attentional functioning in girls with ADHD relative to boys. Objective attention measures may be particularly important in the assessment of attentional improvement in childhood, given known gender biases in ADHD symptom reporting. We emphasize the importance of considering sex and gender-specific factors in ADHD treatment evaluation.

TRIAL REGISTRATIONS

STARS ADHD CHILD: ClinicalTrials.gov ID NCT03649074; STARS ADHD ADOLESCENT: ClinicalTrials.gov ID NCT04897074; STARS ADHD ADULT: ClinicalTrials.gov ID NCT05183919.

A Female-Specific Treatment Group for ADHD-Description of the Programme and Qualitative Analysis of First Experiences

Background: The diagnostics and treatment of attention-deficit/hyperactivity disorder (ADHD) in women remain insufficient. Fluctuations of reproductive hormones during the premenstrual period, postpartum period, and (peri)menopause are neglected, even though they impact ADHD symptoms and associated mood disorders. Therefore, we created a female-specific treatment group for women with ADHD and premenstrual worsening of ADHD and/or mood symptoms. Methods: We describe the group programme and underlying rationale, offering a qualitative analysis of the participants' evaluation. Results: The seven bi-weekly sessions foreground the menstrual cycle and address several ADHD-specific topics in relation to this cyclical pattern. Concurrently, women track their menstrual cycle and (fluctuating) ADHD and mood symptoms with an adjusted premenstrual calendar. In total, 18 women (25-47 years) participated in three consecutive groups. We analysed the evaluation of the last group. Participants experienced the group as a safe and welcoming space. Recognition was valued by all. The topics discussed were deemed valuable, and the structure suited them well. Completing the premenstrual calendar augmented the awareness and recognition of individual cyclical symptoms. A lifespan approach increased self-understanding. Participants took their menstrual cycle more seriously, prioritising self-acceptance and self-care. Conclusions: Exploring a cyclical approach in a group setting seems to be a positive addition to treatment for female ADHD.

Why are females less likely to be diagnosed with ADHD in childhood than males?

ADHD is less likely to be diagnosed in females than males, especially in childhood. Females also typically receive the diagnosis later than males and are less likely to be prescribed ADHD medication. Understanding why these sex differences in clinical care and treatment for ADHD occur is key to improving timely diagnosis in people affected by ADHD. This Personal View is a conceptual review synthesising literature on this topic. This publication considers potential biological explanations (eg, genetic factors), influence of diagnostic practices (eg, criteria suitability, diagnostic overshadowing, and sex-specific diagnostic thresholds), and sociocultural explanations (eg, sex differences in presentation and compensatory behaviours), for the observed sex differences in ADHD clinical practice. This Personal View also outlines future research directions for improving understanding of sex differences in recognition and diagnosis of ADHD.

Attention-deficit/hyperactivity disorder and the menstrual cycle: Theory and evidence

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that exhibits striking sex differences in symptoms, prevalence, and associated problems across development. Etiological factors and mechanisms underlying these sex differences remain one of the most understudied aspects of this disorder. The current paper seeks to provide a novel theoretical framework for understanding this phenomenon by reviewing evidence that females with ADHD may experience a "double whammy" of organizational and activational pubertal hormonal effects. We propose a novel theory of activational effects of cyclical circulating ovarian hormones on ADHD with increasing risk at times of rapid declines in estrogen. These declines may decrease executive function and trait control at two points of the cycle characterized by biphasic affective risk: (1) increases in approach/risk-taking behaviors at mid-cycle (periovulatory) and (2) increases in avoidance/negative affect perimenstrually. Low estrogen and control may then interact with increases in positive and negative affect, respectively, to increase hyperactivity-impulsivity symptoms post-ovulation and inattention symptoms perimenstrually. These interactions may be exacerbated by organizational pubertal effects on relatively overdeveloped limbic circuitry and adolescent-specific social pressures magnified in females with ADHD.

ADHD medication discontinuation and persistence across the lifespan: a retrospective observational study using population-based databases

BACKGROUND

Although often intended for long-term treatment, discontinuation of medication for ADHD is common. However, cross-national estimates of discontinuation are missing due to the absence of standardised measures. The aim of this study was to determine the rate of ADHD treatment discontinuation across the lifespan and to describe similarities and differences across countries to guide clinical practice.

METHODS

We did a retrospective, observational study using population-based databases from eight countries and one Special Administrative Region (Australia, Denmark, Hong Kong, Iceland, the Netherlands, Norway, Sweden, the UK, and the USA). We used a common analytical protocol approach and extracted prescription data to identify new users of ADHD medication. Eligible individuals were aged 3 years or older who had initiated ADHD medication between 2010 and 2020. We estimated treatment discontinuation and persistence in the 5 years after treatment initiation, stratified by age at initiation (children [age 4-11 years], adolescents [age 12-17 years], young adults [age 18-24 years], and adults [age ≥25 years]) and sex. Ethnicity data were not available.

FINDINGS

1 229 972 individuals (735 503 [60%] males, 494 469 females [40%]; median age 8-21 years) were included in the study. Across countries, treatment discontinuation 1-5 years after initiation was lowest in children, and highest in young adults and adolescents. Within 1 year of initiation, 65% (95% CI 60-70) of children, 47% (43-51) of adolescents, 39% (36-42) of young adults, and 48% (44-52) of adults remained on treatment. The proportion of patients discontinuing was highest between age 18 and 19 years. Treatment persistence for up to 5 years was higher across countries when accounting for reinitiation of medication; at 5 years of follow-up, 50-60% of children and 30-40% of adolescents and adults were covered by treatment in most countries. Patterns were similar across sex.

INTERPRETATION

Early medication discontinuation is prevalent in ADHD treatment, particularly among young adults. Although reinitiation of medication is common, treatment persistence in adolescents and young adults is lower than expected based on previous estimates of ADHD symptom persistence in these age groups. This study highlights the scope of medication treatment discontinuation and persistence in ADHD across the lifespan and provides new knowledge about long-term ADHD medication use.

FUNDING

European Union Horizon 2020 Research and Innovation Programme.

Female-specific pharmacotherapy in ADHD: premenstrual adjustment of psychostimulant dosage

Objective

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental condition which is underdiagnosed and undertreated in women. For decades, the ADHD field has called for more insight into female-specific therapy. Preliminary findings postulate that changes in sex hormones during the menstrual cycle may influence the effectiveness of psychostimulant medication. Yet, pharmacotherapeutic interventions tailored to women with ADHD remain scarce. Previously, our group showed an increase in mood symptoms in the premenstrual week in women with ADHD. Premenstrual worsening of depressive and ADHD symptoms represent a treatment challenge. In our adult ADHD clinic, we noted several women describing exacerbation of their ADHD and depressive symptoms in the premenstrual week and/or insufficient effect of their established dosage of psychostimulant. We responded to the need expressed by these women by increasing their stimulant dosage in the premenstrual week, while monitoring the response and side effects.

Methods

This community case study of nine consecutive women being treated for ADHD and co-occurring conditions (including depression and premenstrual dysphoric disorder), reports our local experience of increasing the individually prescribed psychostimulant dosage during the premenstrual period. We methodically monitored the effect of this increased dosage on ADHD symptoms, mood and somatic symptoms for the following 6-24 months.

Results

With premenstrual dose elevation, all nine women experienced improved ADHD and mood symptoms with minimal adverse events. Premenstrual inattention, irritability and energy levels improved, and now resembled the other non-premenstrual weeks more closely. All women decided to continue with the elevated premenstrual pharmacotherapy.

Discussion

Our preliminary results demonstrate potential benefits of increasing premenstrual psychostimulant dosage in women with ADHD, experiencing premenstrual worsening of ADHD and mood symptoms. The results concur with previous findings of diminished response to amphetamines in the late luteal phase. Increased dosage may help combat premenstrual worsening of cognitive and emotional symptoms in women with ADHD, with significant clinical implications. Better management of premenstrual ADHD and mood symptoms in vulnerable women can improve treatment outcome and meet an unmet need. However, implementation should be individually explored. Further investigation of luteal phase psychostimulant dose adjustment is required for safe, optimal and individualised treatment for women with ADHD.

Attention Deficit Hyperactivity Disorder (ADHD) Causes and Diagnosis in Adults: A Review

This article focuses on attention deficit hyperactivity disorder (ADHD) in males of the adult age group, exploring its causes and diagnosis. ADHD is commonly identified in children and teenagers, often leading to academic difficulties. Diagnosing adult ADHD involves evaluating recent symptoms, assessing childhood history, examining functional impairment, obtaining developmental and mental health backgrounds, and ruling out other psychiatric conditions. The diagnostic assessment primarily relies on patient interviews, though input from family members and other sources can be valuable. Men and women show differences in ADHD symptoms and associated neurological conditions, with males more frequently diagnosed with ADHD. Inattention, hyperactivity, and impulsivity are signs of ADHD. The difficulties in identifying adult ADHD and separating it from behavioural problems are covered in the essay. It also explores the various symptoms of ADHD in children and adults and their impact on daily life. The causes of ADHD involve abnormalities in brain structure and function, as well as genetic factors. Treatment options for adult ADHD encompass medication, education, skill training, and psychological counselling. While medications can help manage symptoms, they do not provide a cure. The article concludes by emphasizing the need for a healthy lifestyle alongside therapy and medication to manage ADHD symptoms effectively.

Safety profiles of methylphenidate, amphetamine, and atomoxetine: analysis of spontaneous reports submitted to the food and drug administration adverse event reporting system

Background: Methylphenidate, atomoxetine, and Amphetamine are the three most commonly used medications approved by the United States Food and Drug Administration (FDA) for the treatment of attention deficit/hyperactivity disorder (ADHD). However, a comprehensive analysis of their safety profiles across various age groups and genders in real-world contexts has yet to be conducted. In this study, a pharmacovigilance analysis was performed using the FDA Adverse Event Reporting System (FAERS) database to examine differences in adverse events between methylphenidate, atomoxetine, and Amphetamine. Methods: From January 2014 to September 2022, FAERS reports listing "Methylphenidate," "Dexmethylphenidate," "Atomoxetine," "Amphetamine," "Lisdexamfetamine," "Dextroamphetamine," and "Methamphetamine" as primary suspects were analyzed after removing duplicate reports. We used the standardized Medical Dictionary for Regulatory Activities (MedDRA) query generalized search for adverse events at the preferred term level based on case reports. After filtering duplicate reports, disproportionality analysis was used to detect safety signals according to the proportional reporting ratio (PRR). In order to delve into potential safety concerns, we undertook a two-step analysis of the data. Initially, the data was segmented based on age cohorts: 0-5 years, 6-12 years, 13-18 years, and individuals aged ≥19 years. Following this, after partitioning the data into males and females within the 0-18 years age group, and similarly for those aged ≥19 years, further analysis was conducted. Results: The pharmacovigilance analysis uncovered substantial safety signals in the standardized MedDRA queries. Methylphenidate was associated with dyskinesia (PRR = 21.15), myocardial infarction (PRR = 12.32), and hypertension (PRR = 8.95) in children aged 0-5, 6-12, and 13-18 years, respectively, as well as neonatal exposures via breast milk (PRR = 14.10) in adults aged ≥19 years. Atomoxetine was linked to hostility/aggression (PRR = 15.77), taste and smell disorders (PRR = 6.75), and hostility/aggression (PRR = 6.74) in children aged 0-5, 6-12, and 13-18 years, respectively, as well as hostility/aggression (PRR = 14.00) in adults aged ≥19 years. Amphetamine was associated with psychosis and psychotic disorders (PRR = 16.78), hostility/aggression (PRR = 4.39), and Other ischaemic heart disease (PRR = 10.77) in children aged 0-5 years, 6-12 years, and 13-18 years, respectively, and hostility/aggression in adults aged ≥19 years (PRR = 9.16). Significant and noteworthy adverse event signals were also identified at the preferred term level. Specifically, methylphenidate was associated with myocardial infarction, acute myocardial infarction, coronary artery dissection, electrocardiogram QT prolonged, growth retardation, self-destructive behavior, suicidal ideation, and completed suicide. Atomoxetine was linked to electrocardiogram QT prolonged, growth retardation, and tic. Amphetamine was recorded for coronary artery dissection, suicidal ideation, and completed suicide. It was observed that male patients, including both children and adults, showed a more significant and frequent occurrence of adverse events compared to females, particularly in terms of cardiac disorders. The intensity and quantity of adverse event signals were distinctly different between the two genders, with males having a higher number of signals. All detected safety signals were confirmed using signals obtained from the disproportionality analysis. Conclusion: This pharmacovigilance analysis demonstrated significant variations in the safety profiles of methylphenidate, atomoxetine, and Amphetamine across different age groups and between different genders. Following an in-depth analysis of the FAERS database, we discerned prominent safety signals. Notably, the strength of the signals associated with coronary artery dissection induced by methylphenidate and amphetamine, as well as those related to suicide, demand particular attention. Consequently, it remains imperative to persist in monitoring these medications, assessing the associated risks, and carrying out comparative studies particularly geared towards ADHD drugs.

Safety outcomes of selective serotonin reuptake inhibitors in adolescent attention-deficit/hyperactivity disorder with comorbid depression: the ASSURE study

BACKGROUND

Attention deficit-hyperactivity disorder (ADHD) is related to depressive disorder, and adolescents with both present poor outcomes. However, evidence for the safety of concomitantly using a methylphenidate (MPH) and a selective serotonin reuptake inhibitor (SSRI) among adolescent ADHD patients is limited, a literature gap aimed to address through this investigation.

METHODS

We conducted a new-user cohort study using a nationwide claims database in South Korea. We identified a study population as adolescents who were diagnosed both ADHD and depressive disorder. MPH-only users were compared with patients who prescribed both a SSRI and a MPH. Fluoxetine and escitalopram users were also compared to find a preferable treatment option. Thirteen outcomes including neuropsychiatric, gastrointestinal, and other events were assessed, taking respiratory tract infection as a negative control outcome. We matched the study groups using a propensity score and used the Cox proportional hazard model to calculate the hazard ratio. Subgroup and sensitivity analyses were conducted in various epidemiologic settings.

RESULTS

The risks of all the outcomes between the MPH-only and SSRI groups were not significantly different. Regarding SSRI ingredients, the risk of tic disorder was significantly lower in the fluoxetine group than the escitalopram group [HR 0.43 (0.25-0.71)]. However, there was no significant difference in other outcomes between the fluoxetine and escitalopram groups.

CONCLUSION

The concomitant use of MPHs and SSRIs showed generally safe profiles in adolescent ADHD patients with depression. Most of the differences between fluoxetine and escitalopram, except those concerning tic disorder, were not significant.

Patterns of attention deficit hyperactivity disorder medicine use in the era of new non-stimulant medicines: A population-based study among Australian children and adults (2013-2020)

BACKGROUND AND AIMS

New therapeutic options such as lisdexamfetamine and guanfacine have recently become available for the treatment of attention deficit hyperactivity disorder. We described contemporary patterns of attention deficit hyperactivity disorder medicine use among children, adolescents and adults in Australia.

METHODS

This population-based study used dispensing data for a 10% random sample of Australian residents between July 2012 and December 2020. We estimated the annual prevalence and incidence of attention deficit hyperactivity disorder medicines, second-line guanfacine use and examined concurrent medicine use of both stimulants and non-stimulants. We followed incident users for up to 5 years and analysed treatment persistence using a novel proportion of people covered method. Analyses were stratified by attention deficit hyperactivity disorder medicine, sex and age group; young children (0-5 years), children (6-12 years), adolescents (13-17 years), young adults (18-24 years) and adults (⩾25 years).

RESULTS

We observed a twofold increase in the overall prevalence of attention deficit hyperactivity disorder medicine use between 2013 and 2020, from 4.9 to 9.7 per 1000 persons. Incident use also increased across all age groups and both sexes, with the most pronounced increases among adolescent females (from 1.4 to 5.3 per 1000 persons). Stimulant treatment persistence after 5 years was highest among those initiating treatment as young children (64%) and children (69%) and lowest among those initiating treatment in adolescence (19%). Concurrent use of stimulants and non-stimulants was more common among males and younger age groups. Most children (87%) initiating guanfacine had prior dispensings of attention deficit hyperactivity disorder medicines.

CONCLUSION

We observed increasing attention deficit hyperactivity disorder medicine use in Australia, especially among young females. Nevertheless, treatment rates remain lower than the estimated prevalence of attention deficit hyperactivity disorder across all subpopulations. Poor long-term treatment persistence in adolescence may warrant improved clinical monitoring of attention deficit hyperactivity disorder in patients transitioning from paediatric to adult care. Reassuringly, use of newly approved guanfacine appeared to be in accordance with guidelines among children.

Prepubertal methylphenidate leads to sex-dependent differences in probabilistic discounting

Prescription psychostimulants, such as methylphenidate (MPH), have served as a first line treatment for ADHD and associated developmental disorders since 1961. Psychostimulants has been shown to improve attention, response inhibition, and reduce hyperactivity in patients with ADHD, as well as in non-clinical human populations and animals. While there is a considerable amount of preclinical research investigating the effects of stimulant medications on reward sensitivity and basic learning in male rats, less is understood about their effects in females. Further, there are competing theories on the long-term cognitive impact of MPH, specifically in children who do not have ADHD. To this end, Long-Evans female and male rats were exposed to methylphenidate (0, 2.5, 5 mg/kg, BID, IP) for 20 days during early development (PD10-29). After discontinuation of MPH into adulthood, rats (beginning PD 60) were trained and tested for risk-preference using a 2-choice probabilistic discounting task. For this task, rats were given an option between a 'large-risky' choice (3 sugar pellets delivered on a probabilistic VR schedule) and 'small-certain' choice (1 sugar pellet delivered on a FR schedule). Rats were subsequently tested on an open field conflict test. The results demonstrate that prepubertal exposure to MPH can have lasting effects on decision-making. Specifically, female rats treated with 2.5 mg/kg MPH displayed a decrease in preference for the risky option, whereas male rats treated with the same dose showed an overall increase in preference compared to sex-matched controls. Irrespective of sex, rats treated with 2.5 mg/kg MPH also demonstrated a decrease in anxiety/inhibitory behavior on the modified open field test compared to controls. These results were not due to differences in locomotor behavior. Overall, the study contributes to the growing body of evidence to suggest that MPH exposure early in development can have a sex-dependent impact on decision-making in adulthood.

Annual Research Review: Attention-deficit/hyperactivity disorder in girls and women: underrepresentation, longitudinal processes, and key directions

Attention-deficit/hyperactivity disorder (ADHD) - and its underlying behavioral dimensions of inattention and hyperactivity-impulsivity - have been understudied in females. We first cover the conceptual issues of prevalence, diagnostic practices, diversity, comorbidity, and causal factors, plus forces limiting awareness of ADHD in females. After a narrative review of cross-sectional and longitudinal findings, we conclude the following. (a) Girls meet diagnostic criteria for ADHD at just under half the rates of boys, a ratio that becomes much closer to equal by adulthood. (b) Girls and women with ADHD show a predominance of inattention and associated internalizing problems; boys and men display greater levels of hyperactive-impulsive symptoms and associated externalizing problems. (c) Sex differences in ADHD symptoms and related outcomes depend heavily on the clinical versus nonreferred nature of the samples under investigation. (d) Females with ADHD experience, on average, serious impairments, with a particularly heightened risk for problems in close relationships and engagement in self-harm. (e) Clinicians may overlook symptoms and impairments in females because of less overt (but still impairing) symptom manifestations in girls and women and their frequent adoption of compensatory strategies. Our review of predictors and mediators of adult outcomes highlights (a) the potential for heterotypically continuous pathways in females with childhood ADHD and (b) developmental progressions to self-harm, intimate partner violence, unplanned pregnancy, and comorbid psychopathology. Focusing on ADHD in females is necessary to characterize causal and maintaining mechanisms with accuracy and to foster responsive interventions, as highlighted in our closing list of clinical implications and research priorities.

Clinical characteristics, neuroimaging findings, and neuropsychological functioning in attention-deficit hyperactivity disorder: Sex differences

Recent clinical studies, in both children/adolescents and adults, have shown the extreme neuropsychological heterogeneity of attention-deficit hyperactivity disorder (ADHD): specific neuropsychological deficits have been found only in a minority of individuals, with no direct correlation between discrete cognitive performances and the trajectory of clinical symptoms. Deficits in specific neuropsychological functions may be common in ADHD, but nevertheless no cognitive or neuropsychological profile may fully explain the disorder. Sex differences in the ADHD presentation, both at a neuropsychological and clinical level, also contribute to this clinical and neuropsychological heterogeneity. At a neuropsychological level, females with ADHD may show greater working memory problems, poorer vocabulary skills and worse visual spatial reasoning. Structural and functional imaging study also show discrete differences across sex; however, the great majority of clinical studies mainly or exclusively include male participants with insufficient data to draw firm conclusions on sex differences within the disorder. Here, we report the recent literature data, discussing still open research questions about the clinical presentation, neuroimaging findings, and neuropsychological functioning in ADHD with a focus on the impact of sex differences-a deeper insight in these unresolved issues may have relevant clinical and therapeutic implications for tailored, effective, and long-lasting interventions.

Effects of Atomoxetine Hydrochloride on Regulation of Lifespan in Drosophila Model

Nootropics (smart drugs) are used by students to enhance cognitive performance which have been reported times in recent years. However, some of the nootropics are central nervous system stimulants which are very likely to lead to addiction or complications such as vomiting and dizziness. Are there nootropics that can improve learning behavior while having potential positive effect on health? Here, we reported that Atomoxetine (ATX) has sex-specific effect on prolonging the life span of female Drosophila melanogaster. Further study indicated that ATX enhanced female resistance to heat stress and their vertical climbing ability, but it did decrease the number of eggs laid. ATX increased food-intake and sleep time both of females and males, and significantly reduced the 24h spontaneous activity of females and males. Our results present the sex dimorphic effect of ATX on life span regulation in Drosophila, and support further research on the beneficial role of ATX and the mechanisms in other animal models.

Effects of stimulant medication on divergent and convergent thinking tasks related to creativity in adults with attention-deficit hyperactivity disorder

RATIONALE

Common pharmacological treatments for attention-deficit hyperactivity disorder (ADHD) are central nervous system stimulants acting as norepinephrine-dopamine reuptake inhibitors. The noradrenergic and dopaminergic systems have been shown to impact performance on tasks assessing creativity. Some previous studies suggest higher performance on creativity tasks in ADHD. Stimulant medication has been shown to differentially impact creativity in those without ADHD. However, the full range of effects of stimulant medication on creativity in those with ADHD is not known.

OBJECTIVES

This study examined the effects of stimulants on convergent and divergent tasks associated with creativity in adults with ADHD.

METHOD

Seventeen adults diagnosed with ADHD who were prescribed stimulant medication attended two counterbalanced sessions: one after taking their prescribed stimulant dose and one after the dose was withheld. Participants completed convergent problem-solving (anagrams, Compound Remote Associates) and divergent generative (letter/semantic fluency, Torrance Test for Creative Thinking (TTCT)-Verbal) tasks.

RESULTS

There was a significant increase in words generated on the semantic fluency task for the stimulant session. Additionally, significant increases were found in the stimulant session for originality, flexibility, and fluency scores on the TTCT. Stimulant medication did not have an effect on any of the problem-solving tasks.

CONCLUSIONS

Stimulant medication enhanced verbal fluency in adults with ADHD but had no effect on convergent abilities. Furthermore, stimulants enhanced fluency, flexibility, and originality scores on the TTCT. Therefore, stimulants appear to have positive effects on divergent task performance in adults with ADHD, but not convergent tasks. This finding warrants further studies into the specific roles of norepinephrine and dopamine in this effect.

Methylphenidate for attention-deficit/hyperactivity disorder in adults: a narrative review

RATIONALE

Psychostimulants, including methylphenidate (MPH), are the mainstay of pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD) in adults. Even though MPH is the most commonly used medication for ADHD these days, there are relatively few resources available that provide comprehensive insight into the pharmacological and clinical features of the compound.

OBJECTIVE

The aim of this paper is to provide an up-to-date outline of the pharmacology and clinical utility of MPH for ADHD in adult patients.

METHODS

While conducting the narrative review, we applied structured search strategies covering the two major online databases (MEDLINE and Cochrane Central Register of Controlled Trials). In addition, we performed handsearching of reference lists of relevant papers.

RESULTS

Methylphenidate exhibits multimodal mechanism of action, working primarily as a dopamine and noradrenaline reuptake inhibitor. It also protects the dopaminergic system against the ongoing 'wearing off' (by securing a substantial reserve pool of the neurotransmitter, stored in the presynaptic vesicles). In placebo-controlled trials, MPH was shown to be moderately effective both against the core ADHD symptoms (standardized mean difference [SMD], 0.49; 95% confidence interval [CI], 0.35-0.64), and the accompanying emotion regulation deficits (SMD, 0.34; 95% CI, 0.23-0.45). The most common adverse events related to long-term treatment with MPH are decreased appetite (~ 20%), dry mouth (15%), heart palpitations (13%), gastrointestinal infections (~ 10%), and agitation/feeling restless (~ 10%).

CONCLUSIONS

There is substantial body of evidence to suggest that MPH is an effective and safe treatment option for adults with ADHD.

Treatment of Adolescents with Concurrent Substance Use Disorder and Attention-Deficit/Hyperactivity Disorder: A Systematic Review

Childhood attention-deficit/hyperactivity disorder (ADHD) is a risk factor for the development of substance abuse and substance use disorders (SUD) in adolescence and (early) adulthood. ADHD and SUD also frequently co-occur in treatment-seeking adolescents, which complicates diagnosis and treatment, and is associated with poor treatment outcomes. In this study, we provide a systematic review of controlled studies on the effectiveness of pharmacological, psychosocial, and complementary treatments of ADHD in adolescents with and without comorbid SUD. In addition, we review the longitudinal association between pharmacotherapy for childhood ADHD and the development of SUD in adolescence and early adulthood. We conducted a systematic review of the research literature published since 2000 using Medline, PsycINFO, and the Cochrane Database of Systematic Reviews databases to select randomized clinical trials, observational studies, and meta-analyses. The quality of the evidence from each study was rated using the SIGN grading system. Based on the limited evidence available, strong clinical recommendations are not justified, but provisionally, we conclude that stimulant treatment in children with ADHD may prevent the development of SUD in adolescence or young adulthood, that high-dose stimulant treatment could be an effective treatment for adolescents with ADHD and SUD comorbidity, that cognitive behavior therapy might have a small beneficial effect in these patients, and that alternative treatments are probably not effective. More studies are needed to draw definitive conclusions that will allow for strong clinical recommendations.

Utilization of Drugs for Attention-Deficit Hyperactivity Disorder Among Young Patients in China, 2010-2019

OBJECTIVE

The use of attention-deficit hyperactivity disorder (ADHD) medication is increasing worldwide, but its status in China is unknown. This research aimed to assess the trends of ADHD medication use in young Chinese patients between 2010 and 2019.

METHODS

Dispensing data related to ADHD medication use were extracted from the Hospital Prescription Analysis Cooperative Project of China. The trends in the yearly prescription number of ADHD drugs and corresponding cost were analyzed. We further stratified the data by age, sex, and specific drug.

RESULTS

From 2010 to 2019, sampled prescriptions for ADHD medication increased from 902 to 4531, and the total expenditure increased rapidly from 276,580 to 2,412,308 Chinese Yuan. Prescriptions for males were almost fourfold more than that for females. Patients aged 6-11 years had the highest number of prescriptions for ADHD medication each year, accounting for more than 50% of the total number of prescriptions. The percentage of methylphenidate prescriptions decreased from 91.9% in 2010 to 76.9% in 2019, and the corresponding cost declined from 77.3% to 66.8%. In contrast, atomoxetine prescriptions increased progressively and accounted for about 24.5% of the total prescriptions at the end of the study.

CONCLUSIONS

The use of ADHD drugs and the corresponding cost increased rapidly in China, and methylphenidate was the most frequently prescribed medicine. The increase in ADHD prescriptions requires attention to ensure that it reflects appropriate use, especially in patients aged 6-11 years.