Association Between Single-Dose and Longer Term Clinical Response to Stimulants in Attention-Deficit/Hyperactivity Disorder: A Systematic Review of Randomized Controlled Trials.

Objectives: Stimulants, such as methylphenidate (MPH) and amphetamines, represent the first-line pharmacological option for attention-deficit/hyperactivity disorder (ADHD). Randomized controlled trials (RCTs) have demonstrated beneficial effects at a group level but could not identify characteristics consistently associated with varying individual response. Thus, more individualized approaches are needed. Experimental studies have suggested that the neurobiological response to a single dose is indicative of longer term response. It is unclear whether this also applies to clinical measures. Methods: We carried out a systematic review of RCTs testing the association between the clinical response to a single dose of stimulants and longer term improvement. Potentially suitable single-dose RCTs were identified from the MED-ADHD data set, the European ADHD Guidelines Group RCT Data set (https://med-adhd.org/), as updated on February 1, 2024. Quality assessment was carried out using the Cochrane Risk of Bias (RoB) 2.0 tool. Results: A total of 63 single-dose RCTs (94% testing MPH, 85% in children) were identified. Among these, only a secondary analysis of an RCT tested the association between acute and longer term clinical response. This showed that the clinical improvement after a single dose of MPH was significantly associated with symptom improvement after a 4-week MPH treatment in 46 children (89% males) with ADHD. The risk of bias was rated as moderate. A further RCT used near-infrared spectroscopy, thus did not meet the inclusion criteria, and reported an association between brain changes under a single-dose and longer term clinical response in 22 children (82% males) with ADHD. The remaining RCTs only reported single-dose effects on neuropsychological, neuroimaging, or neurophysiological measures. Conclusion: This systematic review highlighted an important gap in the current knowledge. Investigating how acute and long-term response may be related can foster our understanding of stimulant mechanism of action and help develop stratification approaches for more tailored treatment strategies. Future studies need to investigate potential age- and sex-related differences.

Case Report: Treatment of Akinetic Mutism after Unilateral Anterior Cerebral Artery Infarction with Methylphenidate and Levodopa/Benserazide.

Introduction: Akinetic mutism is a severe state of impaired volition that can result from a stroke. Its therapeutic evidence relies on single case reports that used atomoxetine or levodopa with variable latency and efficacy. Case Presentation: We present the case of a 54-year-old woman who developed akinetic mutism after infarction in the territory of the right anterior cerebral artery, successfully treated with methylphenidate and levodopa/benserazide. Clinical examination showed a patient lacking any spontaneous speech and movement while opening her eyes and fixating. Suspecting akinetic mutism after a comprehensive diagnostic work-up, we started an individual therapy attempt with methylphenidate 10 mg and levodopa/benserazide 100/25 mg twice daily. Both drugs affect the dopaminergic and noradrenergic transmission in the frontal-subcortical circuit, compromised in akinetic mutism. We saw rapid and sustained improvement in her volitional actions, devoid of side effects. Finally, the patient was actively communicating and moving her limbs. Conclusion: We discuss the patient's favorable clinical course in response to the synergistic combination of methylphenidate and levodopa/benserazide, emerging as a promising treatment strategy, and provide a brief literature review of treatment options in akinetic mutism following stroke.

Growing evidence of pharmacotherapy effectiveness in managing attention-deficit/hyperactivity disorder in young children with or without autism spectrum disorder: a minireview.

Many children with autism spectrum disorder (ASD) also have attention-deficit/hyperactivity disorder (ADHD). ADHD in children is associated with increased risk of negative outcomes, and early intervention is critical. Current guidelines recommend psychosocial interventions such as behavioral training as the first line of therapy in managing ADHD symptoms in children with or without ASD. Where symptoms are refractory to these interventions, medications such as stimulants, α2-adrenergic agonist inhibitors, selective norepinephrine reuptake inhibitors, and second-generation antipsychotics are recommended. However, these pharmacotherapies do not have regulatory approval for use in children of preschool age, and evidence on their safety and efficacy in this population has historically been very limited. Since publication of the current guidelines in 2020, several new randomized controlled trials and real-world studies have been published that have investigated the efficacy and tolerability of these medications in preschool children with ADHD, with or without comorbid ASD. Here, we provide a review of the key findings of these studies, which suggest that there is growing evidence to support the use of pharmacological interventions in the management of ADHD in preschool children with comorbid ASD.

Effects of 2 months of methylphenidate on energy expenditure in individuals with obesity: A randomized, double-blind, placebo-controlled pilot study.

Methylphenidate (MPH) has been previously shown to increase resting energy expenditure (REE) in individuals of normal weight; however, the effects on individuals living with obesity are currently unknown. Ten individuals living with obesity were randomly assigned to undergo 60 days of MPH administration with a daily dose of 0.5 mg/kg body weight or a placebo control. REE was measured before and after the 60-day intervention. There was a trend toward significance for group × time interaction on REE (p = 0.082) with a large effect size (η2 = 0.331), with MPH administration increasing REE compared to a decrease in placebo control. Preliminary findings from this pilot study show that MPH has the potential to counter the adaptive thermogenic process commonly seen in weight loss. This is a unique finding among pharmacotherapies, as no approved obesity drugs measurably impact REE.

Effects of methylphenidate on mitochondrial dynamics and bioenergetics in the prefrontal cortex of juvenile rats are sex-dependent.

Methylphenidate (MPH) is a central nervous system stimulant drug and a first order prescription in the treatment of Attention Deficit Hyperactivity Disorder (ADHD). Although MPH biochemistry in neurodevelopment is not completely understood, studies showed it alters energy metabolism in rat brains. ADHD prevalence during neurodevelopment is related to males and the investigation has been mainly done in these subjects, therefore, little is known about MPH action in females and, consequently, about sexual dimorphism. In the present study we evaluated markers of mitochondrial dynamics (DRP1 and MFN2, fission and fusion, respectively), biogenesis (mtTFA) and bioenergetics (respiratory chain complexes) in prefrontal cortex of male and female juvenile rats submitted to exposure to MPH to better understand MPH effect during postnatal neurodevelopment. ATP and oxidative stress levels were also evaluated. Wistar rats received intraperitoneal injection of MPH (2.0 mg/kg) or control (saline), once a day, from 15th to 45th day of age. Results showed that MPH increased DRP1 and decreased MFN2, as well as increased mtTFA in prefrontal cortex of male rats. In female, MPH decreased NRF1 and increased Parkin, which are mitochondrial regulatory proteins. Respiratory chain complexes (complex I, SDH, complexes III and IV), ATP production and oxidative stress parameters were altered and shown to be sex-dependent. Taken together, results suggest that chronic MPH exposure at an early age in healthy animals changes mitochondrial dynamics, biogenesis and bioenergetics differently depending on the sex of the subjects.

Graph analysis uncovers an opposing impact of methylphenidate on connectivity patterns within default mode network sub-divisions.

BACKGROUND: The Default Mode Network (DMN) is a central neural network, with recent evidence indicating that it is composed of functionally distinct sub-networks. Methylphenidate (MPH) administration has been shown before to modulate impulsive behavior, though it is not yet clear whether these effects relate to MPH-induced changes in DMN connectivity. To address this gap, we assessed the impact of MPH administration on functional connectivity patterns within and between distinct DMN sub-networks and tested putative relations to variability in sub-scales of impulsivity. METHODS: Fifty-five right-handed healthy adults underwent two resting-state functional MRI (rs-fMRI) scans, following acute administration of either MPH (20 mg) or placebo, via a randomized double-blind placebo-controlled design. Graph modularity analysis was implemented to fractionate the DMN into distinct sub-networks based on the impact of MPH (vs. placebo) on DMN connectivity patterns with other neural networks. RESULTS: MPH administration led to an overall decreased DMN connectivity, particularly with the auditory, cinguloopercular, and somatomotor networks, and increased connectivity with the parietomedial network. Graph analysis revealed that the DMN could be fractionated into two distinct sub-networks, with one exhibiting MPH-induced increased connectivity and the other decreased connectivity. Decreased connectivity of the DMN sub-network with the cinguloopercular network following MPH administration was associated with elevated impulsivity and non-planning impulsiveness. CONCLUSION: Current findings highlight the intricate effects of MPH administration on DMN rs-fMRI connectivity, uncovering its opposing impact on distinct DMN sub-divisions. MPH-induced dynamics in DMN connectivity patterns with other neural networks may account for some of the effects of MPH administration on impulsive behavior.

Amphetamine and methylphenidate potential on the recovery from stroke and traumatic brain injury: a review.

The prevalence of stroke and traumatic brain injury is increasing worldwide. However, current treatments do not fully cure or stop their progression, acting mostly on symptoms. Amphetamine and methylphenidate are stimulants already approved for attention deficit hyperactivity disorder and narcolepsy treatment, with neuroprotective potential and benefits when used in appropriate doses. This review aimed to summarize pre-clinical and clinical trials testing either amphetamine or methylphenidate for the treatment of stroke and traumatic brain injury. We used PubMed as a database and included the following keywords ((methylphenidate) OR (Ritalin) OR (Concerta) OR (Biphentin) OR (amphetamine) OR (Adderall)) AND ((stroke) OR (brain injury) OR (neuroplasticity)). Overall, studies provided inconsistent results regarding cognitive and motor function. Neurite outgrowth, synaptic proteins, dendritic complexity, and synaptic plasticity increases were reported in pre-clinical studies along with function improvement. Clinical trials have demonstrated that, depending on the brain region, there is an increase in motor activity, attention, and memory due to the stimulation of the functionally depressed catecholamine system and the activation of neuronal remodeling proteins. Nevertheless, more clinical trials and pre-clinical studies are needed to understand the drugs' full potential for their use in these brain diseases namely, to ascertain the treatment time window, ideal dosage, long-term effects, and mechanisms, while avoiding their addictive potential.

Effect of methylphenidate on oculomotor function in individuals with multiple sclerosis: a pilot randomized placebo-controlled trial.

Introduction: Individuals with multiple sclerosis (MS) frequently experience visual and oculomotor symptoms that may impact and confound neuropsychological assessments of information processing speed (IPS). In this study, we examined the effect of the psychostimulant methylphenidate on oculomotor function and the association between change in oculomotor speed and change in information processing speed. Methods: We used a repeated measures crossover design in which a sample of 11 participants with MS were randomly assigned to one of two treatment arms: one that received methylphenidate for 4 weeks and another that received a placebo for 4 weeks. After a 7-day washout period, the treatments were crossed over. The King Devick test, the Symbol Digit Modalities Test, and the Paced Auditory Serial Addition Test were administered at baseline and after each of the two study arms. Results: We found a significant improvement in oculomotor speed in the methylphenidate condition as compared to placebo. This improvement was significantly correlated with improvement on a visuomotor assessment of IPS (Symbol Digit Modalities Test), but no such association was found for an auditory-verbal assessment of IPS (Paced Auditory Serial Addition Test). Discussion: These findings suggest that individuals with MS experience improved oculomotor speed while taking methylphenidate, which may, in turn, improve performance on assessments of IPS with visuomotor demands.

Use of methylphenidate and reporting of valvular heart disease: Global pharmacovigilance analysis in children and adults.

INTRODUCTION: Methylphenidate (MPH) is a common treatment of attention-deficit/hyperactivity disorder (ADHD). Concern has been raised regarding its cardiovascular safety, partly in relation with its micromolar affinity for the 5-HT2B receptor, whose activation may result in valvular heart disease (VHD). METHODS: To explore the association between the use of MPH and VHD reporting, we performed a disproportionality analysis within the WHO global safety database (VigiBase) using data, since inception until March 6th 2024, from: (i) the full database and (ii) different age groups (children/adolescents 6-17 years; adults 18-64 years). To avoid competition bias, safety reports with amphetamine-like appetite suppressants were excluded. Disproportionality was expressed using reporting odds-ratio (ROR) and its 95% confidence interval (CI). RESULTS: Of 29 129 spontaneous reports with MPH, 23 VHD cases (7.9 per 10 000 reports) were identified, including 13 adults and 10 children. Most cases concerned injury on the mitral valve. A disproportionate reporting was observed overall (ROR 1.6, 95% CI 1.1-2.4). Analysis according to age group found that disproportionality in VHD reporting was found in adults only (ROR 2.7, 95% CI 1.6-4.7) but not in children/adolescents (ROR 1.7, 95% CI 0.9-3.2). Furthermore, amongst MPH users only, VHD reporting was higher in adults compared to children (ROR 2.7, 95% CI 1.2-6.3). CONCLUSION: VHD reporting appears rare with MPH compared to other adverse events and is increased in adults only. Our findings support a potential safety signal of VHD in adults exposed to MPH. A risk in that population cannot be excluded and requires further assessment.

Differential Roles of Key Brain Regions: Ventral Tegmental Area, Locus Coeruleus, Dorsal Raphe, Nucleus Accumbens, Caudate Nucleus, and Prefrontal Cortex in Regulating Response to Methylphenidate: Insights from Neuronal and Behavioral Studies in Freely Behaving Rats.

A total of 3102 neurons were recorded before and following acute and chronic methylphenidate (MPD) administration. Acute MPD exposure elicits mainly increases in neuronal and behavioral activity in dose-response characteristics. The response to chronic MPD exposure, as compared to acute 0.6, 2.5, or 10.0 mg/kg MPD administration, elicits electrophysiological and behavioral sensitization in some animals and electrophysiological and behavioral tolerance in others when the neuronal recording evaluations were performed based on the animals' behavioral responses, or amount of locomotor activity, to chronic MPD exposure. The majority of neurons recorded from those expressing behavioral sensitization responded to chronic MPD with further increases in firing rate as compared to the initial MPD responses. The majority of neurons recorded from animals expressing behavioral tolerance responded to chronic MPD with decreases in their firing rate as compared to the initial MPD exposures. Each of the six brain areas studied-the ventral tegmental area, locus coeruleus, dorsal raphe, nucleus accumbens, prefrontal cortex, and caudate nucleus (VTA, LC, DR, NAc, PFC, and CN)-responds significantly (p < 0.001) differently to MPD, suggesting that each one of the above brain areas exhibits different roles in the response to MPD. Moreover, this study demonstrates that it is essential to evaluate neuronal activity responses to psychostimulants based on the animals' behavioral responses to acute and chronic effects of the drug from several brain areas simultaneously to obtain accurate information on each area's role in response to the drug.

Are all ADHD medications created equal? Exploring the differences that enable evening dosing.

With more than 30 available stimulant medications, choosing among therapeutic options for attention-deficit/hyperactivity disorder (ADHD) has become increasingly complex and patient specific. All ADHD stimulants owe their action to variants of either amphetamine or methylphenidate, yet formulation and delivery system differences create unique pharmacokinetic and clinical profiles for each medication. A benefit of the diversity within ADHD pharmacotherapy is that it facilitates tailoring treatment to meet patient needs. Historically, there has been a constant among long-acting stimulant options, regardless of formulation, which was morning dosing. The introduction of delayed-release and extended-release methylphenidate (DR/ER-MPH) is the first long-acting stimulant that patients take in the evening, with the clinical effect delayed until awakening in the morning. This paradigm shift has generated questions among clinicians and continued interest in real-world experience and data. This review used available clinical data, real-world evidence, emerging analyses, and clinical experience to evaluate the characteristics of DR/ER-MPH and its clinical utility within the greater context of ADHD medications and to provide clinicians with practical guidance on the use of DR/ER-MPH in children, adolescents, and adults with ADHD.

Adverse effects of methylphenidate for apathy in patients with Alzheimer's disease (ADMET2 trial).

OBJECTIVES: To examine clinically important adverse events (AEs) associated with methylphenidate (MPH) treatment of apathy in Alzheimer's Disease (AD) versus placebo, including weight loss, vital signs, falls, and insomnia. METHODS: The Apathy in Dementia Methylphenidate Trial 2 (ADMET2) trial was a multicenter randomized, placebo-controlled trial of MPH to treat apathy in individuals with apathy and AD. Participants in ADMET2 had vital signs and weight measured at monthly visits through 6 months. AEs, including insomnia, falls, and cardiovascular events, were reported at every visit by participants and families using a symptom checklist. RESULTS: The study included 98 participants in the MPH group and 101 in the placebo group. Participants in the MPH group experienced greater weight loss on average than the placebo through the 6-month follow-up, with a difference in change between MPH and placebo of 2.8 lb (95% confidence interval, CI: 0.7, 4.9 lb). No treatment group differences in change during the trial were found in systolic and diastolic blood pressure. More participants in the MPH group reported falls during the follow-up, 10 versus 6 in MPH and placebo groups, respectively. No differences in post-baseline insomnia were observed between the treatment groups. No participants reported instances of myocardial infarction, congestive heart failure, arrhythmia, stroke, or cardiomyopathy throughout the study period. CONCLUSIONS: MPH use in AD patients for treating apathy is relatively safe, particularly notable given the many medical comorbidities in this population. There was a statistically significant but modest weight loss associated with MPH use, and clinicians are thus advised to monitor weight during MPH treatment.

Erratum: Role of environmental enrichment on social interaction, anxiety, locomotion, and memory in Wistar rats under chronic methylphenidate intake.

[This corrects the article DOI: 10.3389/fnbeh.2023.1251144.].

Repetitive mild traumatic brain injury impairs norepinephrine system function and psychostimulant responsivity.

Traumatic brain injury (TBI) is a complex pathophysiological process that results in a variety of neurotransmitter, behavioral, and cognitive deficits. The locus coeruleus-norepinephrine (LC-NE) system is a critical regulator of arousal levels and higher executive processes affected by TBI including attention, working memory, and decision making. LC-NE axon injury and impaired signaling within the prefrontal cortex (PFC) is a potential contributor to the neuropsychiatric symptoms after single, moderate to severe TBI. The majority of TBIs are mild, yet long-term cognitive deficits and increased susceptibility for further injury can accumulate after each repetitive mild TBI. As a potential treatment for restoring cognitive function and daytime sleepiness after injury psychostimulants, including methylphenidate (MPH) that increase levels of NE within the PFC, are being prescribed "off-label". The impact of mild and repetitive mild TBI on the LC-NE system remains limited. Therefore, we determined the extent of LC-NE and arousal dysfunction and response to therapeutic doses of MPH in rats following experimentally induced single and repetitive mild TBI. Microdialysis measures of basal NE efflux from the medial PFC and arousal measures were significantly lower after repetitive mild TBI. Females showed higher baseline PFC-NE efflux than males following single and repetitive mild TBI. In response to MPH challenge, males exhibited a blunted PFC-NE response and persistent arousal levels following repetitive mild TBI. These results provide critical insight into the role of catecholamine system dysfunction associated with cognitive deficits following repeated injury, outcome differences between sex/gender, and lack of success of MPH as an adjunctive therapy to improve cognitive function following injury.

The effects of chronic administration of stimulant and non-stimulant medications on executive functions in ADHD: A systematic review and meta-analysis.

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with executive function deficits that are improved with medications. However, meta-analyses of stimulant effects on cognition have mostly tested single-dose effects, and there is no meta-analysis of non-stimulant effects. This systematic review and meta-analysis tested the clinically more relevant longer-term effects of Methylphenidate (20 studies; minimum 1 week) and Atomoxetine (8 studies; minimum 3 weeks) on reaction time, attention, inhibition, and working memory, searching papers on PubMed, Embase, Ovid MEDLINE, and PsycINFO. The meta-analysis of 18 studies in 1667 subjects showed that methylphenidate was superior to placebo in all cognitive domains with small to medium effect sizes (Hedges g of 0.34-0.59). The meta-analysis of atomoxetine included 7 studies in 829 subjects and showed no effects in working memory, but superior effects in the other domains with medium to large effect sizes (Hedge's g of 0.36-0.64). Meta-regression analysis showed no drug differences on cognitive effects. The meta-analyses show for the first time that chronic Methylphenidate and Atomoxetine have comparable effects of improving executive functions in people with ADHD.

Effects of Catecholaminergic and Transcranial Direct Current Stimulation on Response Inhibition.

BACKGROUND: The principle of gain control determines the efficiency of neuronal processing and can be enhanced with pharmacological or brain stimulation methods. It is a key factor for cognitive control, but the degree of how much gain control may be enhanced underlies a physical limit. METHODS: To investigate whether methylphenidate (MPH) and transcranial direct current stimulation (tDCS) share common underlying mechanisms and cognitive effects, we administered MPH and anodal tDCS (atDCS) over the right inferior frontal gyrus both separately and combined, while healthy adult participants (n = 104) performed a response selection and inhibition task. The recorded EEG data were analyzed with a focus on theta band activity, and source estimation analyses were conducted. RESULTS: The behavioral data show that MPH and atDCS revealed interactive effects on the ability to inhibit responses. Both MPH and atDCS modulated task-related theta oscillations in the supplementary motor area when applied separately, making a common underlying mechanism likely. When both stimulation methods were combined, there was no doubling of effects in the supplementary motor area but a shift to inferior frontal areas in the cortical network responsible for theta-driven processing. CONCLUSIONS: The results indicate that both MPH and atDCS likely share a common underlying neuronal mechanism, and interestingly, they demonstrate interactive effects when combined, which are most likely due to the physical limitations of gain control increases. The current study provides critical groundwork for future combined applications of MPH and non-invasive brain stimulation.

Methylphenidate, but not citalopram, decreases impulsive choice in rats performing a temporal discounting task.

Introduction: Drugs targeting monoamine systems remain the most common treatment for disorders with impulse control impairments. There is a body of literature suggesting that drugs affecting serotonin reuptake and dopamine reuptake can modulate distinct aspects of impulsivity - though such tests are often performed using distinct behavioral tasks prohibiting easy comparisons. Methods: Here, we directly compare pharmacologic agents that affect dopamine (methylphenidate) vs serotonin (citalopram) manipulations on choice impulsivity in a temporal discounting task where rats could choose between a small, immediate reward or a large reward delayed at either 2 or 10s. In control conditions, rats preferred the large reward at a small (2s) delay and discounted the large reward at a long (10s) delay. Results: Methylphenidate, a dopamine transport inhibitor that blocks reuptake of dopamine, dose-dependently increased large reward preference in the long delay (10s) block. Citalopram, a selective serotonin reuptake inhibitor, had no effect on temporal discounting behavior. Impulsive behavior on the temporal discounting task was at least partially mediated by the nucleus accumbens shell. Bilateral lesions to the nucleus accumbens shell reduced choice impulsivity during the long delay (10s) block. Following lesions, methylphenidate did not impact impulsivity. Discussion: Our results suggest that striatal dopaminergic systems modulate choice impulsivity via actions within the nucleus accumbens shell, whereas serotonin systems may regulate different aspects of behavioral inhibition/impulsivity.

Qualitative study of the lived experience of methylphenidate prescribed for children with a fetal alcohol spectrum disorder.

Fetal Alcohol Spectrum Disorders (FASD) refer to physical, cognitive, and behavioural symptoms in an individual whose mother consumed alcohol during pregnancy. It is the leading cause of non-genetic avoidable mental disability, with an estimated worldwide prevalence of 1%. Attention Deficit Hyperactivity Disorder (ADHD) diagnostic criteria are met for 50-80% of patients with FASD. Methylphenidate (MPH) is the first-line pharmacological treatment for ADHD. This study aims to explore the lived experience of children with FASD taking MPH and their caregivers to adapt prescribing modalities by considering different ways to administer the drugs. We hope to improve the therapeutic alliance between the children and their caregivers by gaining an insiders' view of the medication perception. Semi-structured interviews with children and their caregivers were conducted in this qualitative study. Data collection by purposive sampling continued until we reached theoretical sufficiency. Data were analysed using interpretative phenomenological analysis. We conducted 16 semi-structured interviews: 8 with the children aged 7-12, 5 boys and 3 girls and 8 with their caregivers. The analysis showed that inadequate palatability and capsule form experiences were the leading causes of children's non-adherence to the treatment. MPH appeared to be a valuable aid for caregivers even if they had concerns about its potential toxicity. However, it is necessary to identify caregivers' expectations concerning MPH to adapt the prescription in terms of choice of specialty and intake modalities. Regular support was required to reduce caregivers' fears of dependence, personality transformation and long-term adverse effects. Information on palatability should be given when prescribing MPH to children with ADHD as well as its possible side effects or toxicity. It highlights the need for further studies of the experience of palatability of drugs prescribed to children. When prescribing a treatment, children should be more involved in medical counselling and it is necessary to understand the child's perspectives to co-construct common representations for better therapeutical adherence.

A Post-Hoc Analysis of Emotional Lability With Delayed-Release/Extended-Release Methylphenidate in Children Aged 6 to 12 Years of Age Participating in Two Phase 3 Clinical Trials.

OBJECTIVE: DR/ER-MPH (formerly HLD200) is an evening-dosed delayed-release and extended-release methylphenidate approved for the treatment of ADHD in patients ≥6 years. Post hoc analyses of two pivotal Phase 3 trials: HLD200-107 (NCT02493777) and HLD200-108 (NCT02520388) evaluated emotional lability (EL) with DR/ER-MPH treatment. METHODS: Differences in Conners Global Index-Parent (CGI-P) EL subscale scores and age- and gender-adjusted T-scores over an open-label titration phase (HLD200-107) and between treatment and placebo groups at endpoint (HLD200-108) were evaluated. RESULTS: In HLD200-107 (N = 117) mean CGI-P EL subscale scores improved from 5.3 to 1.3 (p < .0001) after 6 weeks; in HLD200-108 significant improvements were observed in the treatment group (n = 81) versus placebo (n = 80; 3.11 vs. 4.08; p = .0053). T-scores showed an improvement with DR/ER-MPH treatment in both trials. Few emotional adverse events (AEs) were reported. CONCLUSION: DR/ER-MPH treatment resulted in statistically significant improvements in EL to the level of non-ADHD peers as contextualized by T-scores.

Developmental exposure to 17-α-hydroxyprogesterone caproate disrupts decision-making in adult female rats: A potential role for a dopaminergic mechanism.

The synthetic progestin, 17α-hydroxyprogesterone caproate (17-OHPC), is administered to pregnant individuals at risk for preterm birth and is likely transferred from mother to fetus. Yet, there is little information regarding the potential effects of 17-OHPC administration on behavioral and neural development in offspring. In rats, neonatal 17-OHPC exposure altered dopaminergic fiber distribution and density in the prelimbic medial prefrontal cortex (mPFC) in neonates and adolescents, respectively. Additionally, neonatal 17-OHPC exposure in male rats increased response omissions in a delay discounting task of impulsive decision-making. Because developmental 17-OHPC exposure has differential effects in males and females, investigating the effects of 17-OHPC on impulsive decision-making in female rats is necessary. The present study tested the effects of developmental 17-OHPC exposure (P1-P14) in a delay discounting task in which female rats chose between a small immediate reward and a larger delayed (0, 15 30, or 45 s) reward. 17-OHPC-exposed females made more omissions than controls. There was no effect of 17-OHPC on large reward preference nor on response time, and omissions were similar during both free- and forced-choice trials. The present study also aimed to investigate the neural mechanisms underlying omissions in 17-OHPC-exposed female rats. The dopamine transporter inhibitor, methylphenidate (MPH), was administered prior to delay discounting testing. MPH treatment did not reduce omissions in 17-OHPC-exposed females. If anything, MPH increased omissions in control females nearly fourfold during the longest delays. These results suggest that developmental 17-OHPC exposure increased omissions without affecting impulsivity or slowing decision-making. Furthermore, omissions may be regulated, at least in part, by dopaminergic mechanisms.