Attention-deficit/hyperactivity Disorder Symptoms In Children Research Articles

Adverse Childhood Experiences and ADHD Symptoms Among French College Students.

To examine the relationship between adverse childhood experiences (ACEs) and Attention-deficit Hyperactivity Disorder (ADHD) among college students. We investigated the association between ACEs and ADHD symptoms among French college students enrolled in the i-Share cohort using multivariate logistic regression models. The sample comprised of 1062 participants with a mean age of 20.3 (SD = 2.3) of which 30.6% had no ACEs exposure, 29.6% had 1 ACE, 19.2% had 2 ACEs, and 20.6% had ≥ 3 ACEs. After controlling for potential confounders, every increase in ACE exposure heightened the risk of ADHD symptoms with the respective adjusted Odds Ratios and 95% confidence intervals: 1 ACE: 2.1 (0.7-6.3) / 2 ACEs: 4.5 (2.6-12.8)/ ≥ 3 ACEs: 5.2 (1.8-14.8). Estimates for ADHD symptoms were higher with sexual abuse, emotional and physical neglect, and bullying. Findings suggest that ACEs heighten the risk for developing ADHD symptoms among college students and bear important implications for prevention and clinical practice.

Comparison of Horse and Cow Milk on the Symptoms of Attention Deficit Hyperactivity Disorder in Children: A Cross-Over Clinical Trial Study

Numerous researchers have examined the effect of diet on Attention Deficit Hyperactivity Disorder (ADHD). The purpose of this study is to compare the symptoms of ADHD in children fed horse milk versus conventionally fed cow's milk. Thirty patients aged 6 to 14 with ADHD were randomly selected and divided into two groups in this randomized double-blind crossover study. All patients completed a 45-day period of consuming 250 mL horse or cow milk, as well as continued Ritalin (1 mg/kg) treatment. The wash out period was considered one week. Symptoms are recorded using the Conners rating scale (CS). The CS of the parents decreased significantly (P value≤0.001) in the group that first received horse milk, but increased (P value=0.007) after consuming cow's milk. After consumption of horse milk, the parent's CS was significantly different from that of cow milk (P value= 0.001). Teachers' CS decreased significantly following horse milk consumption (P=0.001) and increased significantly following cow milk consumption (P=0.028) in this group. The average teacher's CS after cow milk differed significantly from that after horse milk (P value= 0.024). The CS of the parents did not change significantly (P value=0.913) in the group that first consumed cow's milk. However, it was significantly decreased (P value=0.004) after receiving horse milk. The CS of the teachers in this group did not change after the cow's milk (P value=0.282). However, following the administration of horse milk, the mean of CS decreased significantly (P=0.003). The average of the teacher's CS after consuming cow milk differed significantly from that of horse milk (P value= 0.010). In both groups, there was no significant difference in the mean of parents and teachers CS before and after the washout period (P>0.05). According to the study, horse milk consumption was significantly more effective than cow milk at lowering scores.

Feasibility and Efficacy of the Alert Program® for Children with Attention-Deficit/Hyperactivity Disorder.

This study explored the feasibility and initial efficacy of a sensorimotor intervention to improve symptoms of attention-deficit/hyperactivity disorder (ADHD). Twenty-seven children (ages 8-12years) with ADHD and their parents participated in an 8-week group intervention based on The Alert Program® for Self-Regulation (AP). Families were taught to recognize child arousal states and to use sensorimotor strategies to manage levels of alertness. Parent and teacher reports of child attention symptoms were collected at baseline, before and after intervention. Objective ratings of child problem behaviours and use of sensorimotor strategies during computerized tasks of visual and auditory attention were also coded before and after intervention. Parents and children endorsed high acceptability and satisfaction for the AP treatment. Parental ratings indicated increased knowledge and use of sensorimotor strategies, and decreased child ADHD symptoms at home from pre-AP to post-AP. However, no significant changes in child outcomes were reported by teachers. Unexpectedly, observed child problem behaviours during the visual attention task increased from pre-AP to post-AP. The AP was received positively by parents and children with improvements in regulation strategies and child attention at home, but more work needs to be done to generalize the effects to school and other peer settings.

Predicting childhood ADHD-linked symptoms from prenatal and perinatal data in the ABCD cohort.

This study investigates the capacity of pre/perinatal factors to predict attention-deficit/hyperactivity disorder (ADHD) symptoms in childhood. It also explores whether predictive accuracy of a pre/perinatal model varies for different groups in the population. We used the ABCD (Adolescent Brain Cognitive Development) cohort from the United States (N = 9975). Pre/perinatal information and the Child Behavior Checklist were reported by the parent when the child was aged 9-10. Forty variables which are generally known by birth were input as potential predictors including maternal substance-use, obstetric complications and child demographics. Elastic net regression with 5-fold validation was performed, and subsequently stratified by sex, race/ethnicity, household income and parental psychopathology. Seventeen pre/perinatal variables were identified as robust predictors of ADHD symptoms in this cohort. The model explained just 8.13% of the variance in ADHD symptoms on average (95% CI = 5.6%-11.5%). Predictive accuracy of the model varied significantly by subgroup, particularly across income groups, and several pre/perinatal factors appeared to be sex-specific. Results suggest we may be able to predict childhood ADHD symptoms with modest accuracy from birth. This study needs to be replicated using prospectively measured pre/perinatal data.

Association between attention-deficit/hyperactivity symptoms and sleep in preschoolers

IntroductionSleep problems are frequent in children with attention-deficit/hyperactivity disorder (ADHD). Some authors have tried to characterize paediatric sleep habits in Portugal, but none has focused on preschool-age children nor attempted to establish their association with ADHD. We aimed to assess the prevalence of ADHD symptoms in preschool-age children and to study their association with sleep habits. Material and methodsWe conducted a cross-sectional study. We distributed questionnaires to a random sample of caregivers of children enrolled in early childhood education centres in Porto. We collected data on sociodemographic characteristics, television watching and outdoor activities. We assessed ADHD symptoms and sleep habits with the Portuguese versions of the Conners’ Parents Rating Scale, Revised and the Children’s Sleep Habits Questionnaire (CSHQ-PT), respectively. ResultsThe study included 381 preschoolers (50.90% male). We found high scores for ADHD symptoms in 13.10%, with a higher prevalence in girls (14.40% vs. 11.85%; P = 0.276). In the CSHQ-PT, 45.70% of participants had a mean total score greater than 48, which is the cut-off point applied in the screening of sleep disturbances in the Portuguese population. There was a significant association between high scores for ADHD symptoms and a lower maternal education level (P < 0.001), a shorter sleep duration (P = 0.049), and higher scores on parasomnias (P = 0.019) and sleep disordered breathing (P = 0.002) in CSHQ-PT subscales. ConclusionsADHD and sleep disorders are common in preschoolers, in Porto, and this study suggests some clinical correlations between them. Since these interactions are complex and far from being elucidated, further studies are paramount to provide guidance for prevention and managing strategies in younger children at risk for ADHD.

Associations of neurodevelopmental risk factors with psychosis proneness: Findings from a non-clinical sample of young adults

Psychotic disorders often develop as the continuum of subclinical symptoms that include hallucination-like and delusion-like experiences, and are commonly referred to as psychotic-like experiences (PLEs). To date, a number of neurodevelopmental risk factors of psychosis have been detected, yet their mutual interplay remains unknown. Therefore, we aimed to investigate the additive association of childhood trauma history, reading disabilities and symptoms of attention-deficit/hyperactivity disorder (ADHD) with psychosis proneness. A total of 3000 young adults (58.3% females, aged 18–35 years) with a negative history of psychiatric treatment were recruited to the cross-sectional study through computer-assisted web interview. Self-reports were administered to measure childhood trauma history, ADHD symptoms and reading disabilities. Linear regression analyses revealed significant main associations of childhood trauma history and reading disabilities with higher levels of PLEs. There were no significant main associations of ADHD with the level of PLEs. However, the associations of all possible interactions between neurodevelopmental risk factors with the level of PLEs were significant. Our findings suggest that childhood trauma history and reading disabilities may additively increase a risk of psychosis. The present findings bring new implications for early intervention strategies in psychosis and posit the rationale of recording the accumulation of neurodevelopmental vulnerabilities in clinical practice.

ADHD Symptoms Increased During the Covid-19 Pandemic: A Meta-Analysis

Objective: Emerging research suggests that the Covid-19 pandemic has disproportionately and adversely affected children with Attention-Deficit/Hyperactivity Disorder (ADHD). The purpose of this meta-analysis is to consolidate the findings from studies that examined changes in ADHD symptoms from before to during the pandemic. Method: Database searches of PsycINFO, ERIC, PubMed, and ProQuest were used to identify relevant studies, theses, and dissertations. Results: A total of 18 studies met specific inclusion criteria and were coded based on various study characteristics. Twelve studies examined ADHD symptoms longitudinally and six studies assessed ADHD symptoms retroactively and during the pandemic. Data from 6,491 participants from 10 countries were included. Results indicated that many children and/or their caregivers reported an increase in child ADHD symptoms during the Covid-19 pandemic. Conclusions: This review points to a global increase in ADHD symptoms and has implications for the prevalence and management of ADHD during the post-pandemic recovery.

Methylphenidate dose–response in children with ADHD: evidence from a double-blind, randomized placebo-controlled titration trial

Methylphenidate (MPH) is highly efficacious in reducing symptoms of attention-deficit/hyperactivity disorder (ADHD) in children. Generally increased doses are found to result in better symptom control; however, it remains unclear whether this pattern can be observed at the individual level, given the large heterogeneity in individual dose–response relationships and observed placebo responses. A double-blind, randomized, placebo-controlled cross-over trial was used to compare weekly treatment with placebo and 5, 10, 15 and 20 mg of MPH twice daily on parent and teacher ratings of child ADHD symptoms and side effects. Participants were 5–13-year-old children with a DSM-5 diagnosis of ADHD (N = 45). MPH response was assessed at group and individual levels and predictors of individual dose–response curves were examined. Mixed model analysis showed positive linear dose–response curves at group level for parent and teacher rated ADHD symptoms and parent rated side effects, but not for teacher rated side effects. Teachers reported all dosages to improve ADHD symptoms compared to placebo, while parents only reported > 5 mg/dose as effective. At the individual level, most (73–88%) children, but not all, showed positive linear dose–response curves. Higher severity of hyperactive-impulsive symptoms and lower internalizing problems, lower weight, younger age and more positive opinions towards diagnosis and medication partly predicted steeper linear individual dose–response curves. Our study confirms that increased doses of MPH yield greater symptom control at a group level. However, large interindividual variation in the dose–response relationship was found and increased doses did not lead to greater symptom improvement for all children. This trial was registered in the Netherlands trial register (# NL8121).

DNA methylation is associated with prenatal exposure to sulfur dioxide and childhood attention-deficit hyperactivity disorder symptoms

Epigenetic influence plays a role in the association between exposure to air pollution and attention deficit hyperactivity disorder (ADHD); however, research regarding sulfur dioxide (SO2) is scarce. Herein, we investigate the associations between prenatal SO2 exposure and ADHD rating scale (ARS) at ages 4, 6 and 8 years repeatedly in a mother–child cohort (n = 329). Whole blood samples were obtained at ages 2 and 6 years, and genome-wide DNA methylation (DNAm) was analyzed for 51 children using the Illumina Infinium HumanMethylation BeadChip. We analyzed the associations between prenatal SO2 exposure and DNAm levels at ages 2 and 6, and further investigated the association between the DNAm and ARS at ages 4, 6 and 8. Prenatal SO2 exposure was associated with ADHD symptoms. From candidate gene analysis, DNAm levels at the 6 CpGs at age 2 were associated with prenatal SO2 exposure levels. Of the 6 CpGs, cg07583420 (INS-IGF2) was persistently linked with ARS at ages 4, 6 and 8. Epigenome-wide analysis showed that DNAm at 6733 CpG sites were associated with prenatal SO2 exposure, of which 58 CpGs involved in Notch signalling pathway were further associated with ARS at age 4, 6 and 8 years, persistently. DNAm at age 6 was not associated with prenatal SO2 exposure. Changes in DNAm levels associated with prenatal SO2 exposure during early childhood are associated with increases in ARS in later childhood.

The role of single trial variability in event related potentials in children with attention deficit hyperactivity disorder

ObjectiveChildren with attention deficit hyperactivity disorder (ADHD) show attenuated mean P3 component amplitudes compared to typically developing (TD) children. This finding may be the result of individual differences in P3 amplitudes, P3 latencies, and/or greater single trial variability (STV) in amplitude or latency, suggesting neural “noise.” MethodsEvent related potentials (ERPs) from 75 children with ADHD and 29 TD children were recorded with electroencephalography (EEG). Caregivers provided ratings on child ADHD symptoms. Single-trial ERP amplitudes and latencies were extracted from the P3 component time window during a visual oddball task. Additionally, we computed individual-centered and trial-centered P3 amplitudes to account for inter-individual and inter-trial variability in the timing of the P3 peak. ResultsIn line with prior research, greater ADHD symptom severity was associated with reduced mean P3 amplitude. This correlation was no longer significant after correcting for inter-trial differences in P3 latency. In contrast, greater ADHD symptom severity was associated with reduced STV in P3 amplitude. ConclusionsOur results suggest that attenuated average P3 amplitude in ADHD samples is due to a consistent reduction in strength of the neurophysiological signal at the single trial level, as well as increased inter-trial variability in the timing of P3 peak amplitudes. The traditional method of extracting P3 amplitudes based on a single time window for all trials may not adequately capture variability in P3 latencies associated with ADHD. SignificanceInter- and intra-individual differences in brain signatures should be considered in models of neurobiological differences in neurodevelopmental samples.

Epilepsy severity mediates association between mutation type and ADHD symptoms in tuberous sclerosis complex.

The association between attention-deficit/hyperactivity disorder (ADHD) and tuberous sclerosis complex (TSC) is widely reported, with support for the role of epilepsy, yet the mechanisms underlying the association across development are unclear. The Tuberous Sclerosis 2000 Study is a prospective longitudinal study of TSC. In Phase 1 of the study, baseline measures of epilepsy, cortical tuber load, and mutation were obtained with 125 children ages 0-16 years. In Phase 2, at an average of 8 years later, ADHD symptoms were measured for 81 of the participants. Structural equation modeling revealed an indirect pathway from genetic mutation, to cortical tuber load, to epileptic spasm severity in infancy, to ADHD symptoms in middle childhood and adolescence, in addition to a pathway linking current seizure severity to ADHD symptoms. Findings were retained when intelligence quotient (IQ) was entered as a correlated factor. The findings support a cascading developmental pathway to ADHD symptoms mediated by early-onset and severe epilepsy in the first 2 years of life. This warrants detailed investigation of seizure characteristics and cognitive and behavioral sequelae associated with ADHD from early in life, to further the understanding of the association between ADHD and early-onset epilepsy across syndromic and non-syndromic populations.

Prevalence of Attention Deficit Hyperactivity Disorder and Sluggish Cognitive Tempo Symptoms in Children Presenting with Foreign Body Ingestion: A Case-Control Study

Foreign body ingestion (FBI) is one of the common causes of emergency admissions in infancy and childhood. Although the large majority of children who present with the FBI have no psychiatric diagnosis, present studies demonstrate that attention deficit hyperactivity disorder (ADHD) and related psychiatric problems might be a risk factor for FBI. This study aimed to compare the demographic variables and attention deficit hyperactivity disorder levels and sluggish cognitive tempo symptoms (ADHD-SCT) in children who ingested foreign bodies with healthy children. Also, we aimed to address the relationship between ADHD-SCT symptoms and the age of FBI. The FBI group comprised 44 children (age 2-8, median age: 5, 68.2% boys) admitted to the emergency, pediatric surgery, and pediatric gastroenterology department after FBI, and the healthy control group comprised 30 children (age 3-8, median age: 6, 56.7% boys). We administered the sociodemographic information form, SNAP-IV ADHD rating scale, and Barkley’s child SCT ratings scale to both groups of parents. Our results demonstrated that maternal education level was significantly lower in the FBI group, although other demographic characteristics of the samples were similar (p=0.023). In addition, ADHD-hyperactivity/impulsivity scores were significantly higher in the FBI group (p=0.01). Still, there were no significant differences in ADHD-inattention, SCT-daydreaming, and SCT-sluggishness scores (for all, p&gt;0.05). We found positive-moderate relationships between SCT-daydreaming and sluggishness symptoms and FBI age (r=0.314, r=0.348, respectively). This means that higher SCT scores are related to an older FBI age. In conclusion, for the first time, we evaluated the ADHD and SCT symptoms in young children against FBI and found that ADHD-hyperactivity, but not ADHD-inattention symptoms, were significantly higher in the FBI group, and SCT symptoms increase the risk of FBI at an older age. In addition, we found that a lower maternal education level could be an additional risk factor for FBI. Despite the high hyperactivity in the FBI group, the low rate of child psychiatry evaluation should be considered when evaluating a child.

Research Review: A systematic review and meta-analysis of infant and toddler temperamentaspredictors of childhood attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with onset as early as preschool and impairment across the lifespan. Temperament factors, specifically those that theoretically map onto ADHD symptoms, may be early markers of risk for developing later childhood ADHD that could be identifiable in infancy or toddlerhood. This meta-analysis examined the associations between these early temperamental factors and later symptoms and diagnosis of ADHD and mapped early temperament constructs onto the three ADHD symptom dimensions. A systemic review of the literature was conducted to identify prospective longitudinal studies that included theoretically relevant temperament constructs (sustained attention, activity level, inhibition, and negative emotionality) examined from birth to 36 months old and ADHD (symptoms or diagnosis) in preschool or childhood. The association between each temperament construct and ADHD outcomes was examined using pooled standardized estimates in meta-analyses. Forty-eight articles (n=112,716 infants/toddlers) prospectively examined temperament and the relation to childhood ADHD symptoms or diagnosis. Activity level (k=18) in infancy and toddlerhood was moderately associated with childhood ADHD (r=.39, CI=0.27, 0.51, p < .001). Moderate effect sizes were also observed for sustained attention (k=9; r=-.28, CI=-0.42, -0.12, p < .001) and negative emotionality (k=33; r=.25, CI=0.16, 0.34, p < .001) with ADHD. The specificity of each temperament construct for later ADHD symptom dimensions was such that activity level and negative emotionality were predictive of all three symptom dimensions (i.e., inattention, hyperactivity/impulsivity, and combined), whereas sustained attention was only associated with combined symptoms. Infant and toddler temperament is an early risk factor for the development of childhood ADHD that could be utilized for early intervention identification. Yet, this systematic review found that relatively few prospective longitudinal studies have examined sustained attention (k=9) and inhibition (k=15) in infancy and toddlerhood in relation to later ADHD highlighting the need for further research.

The impact of neurofeedback training on midbrain activity and symptoms of attention- deficit/hyperactivity disorder (ADHD) in early childhood: a review study

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterized by hyperactivity, inattention, and impulsivity symptoms that can significantly impair a child's functioning and quality of life. Neurofeedback, a form of biofeedback, has emerged as a promising therapeutic approach for ADHD, utilizing real-time feedback of brain activity to help individuals self-regulate their brain function. This review paper examines the existing literature on the impact of neurofeedback training on midbrain activity and symptoms of ADHD in young children. The review begins with an overview of ADHD and its current treatment approaches, including medication and behavioural interventions. Then it delves into neurofeedback and how it works, focusing on targeting midbrain activity as a potential modality for ADHD treatment. The review discusses findings from empirical studies that have investigated the impact of neurofeedback training on midbrain activity and symptoms of ADHD in young children, including randomized controlled trials (RCTs), quasi-experimental studies, and case studies. Further, critically evaluated the methodological rigor and limitations of the studies, including sample size, study design, and outcome measures used. It also highlights the findings and trends in the literature, including the potential benefits of neurofeedback training in improving midbrain activity and reducing ADHD symptoms in young children. Then, underlying mechanisms of neurofeedback and its potential as a non- pharmacological intervention for ADHD, including long-term effects and the need for further research are discussed. Finally, the researcher summarizes the findings and implications for clinical practice, highlighting the potential of neurofeedback training as an adjunct or alternative treatment for ADHD in young children. The limitations and future directions for research in this area are discussed to establish the efficacy and safety of neurofeedback training for young children with ADHD.)

Efficacy and tolerability of psychostimulants for symptoms of attention-deficit hyperactivity disorder in preschool children: A systematic review and meta-analysis.

There was no previous meta-analysis investigating the efficacy/tolerability of psychostimulants for symptoms of attention-deficit hyperactivity disorder (ADHD) in preschool children. Databases including PubMed, the Cochrane Library, EMBASE, ScienceDirect, and ClinicalTrials.gov were searched from inception to March 2022 for randomized controlled trials (RCTs) on therapeutic efficacy of psychostimulants against ADHD symptoms in preschool children (age ≤6 years) compared with placebos. Primary outcomes were (a) changes in ADHD symptoms evaluated by validated rating scales from parents'/teacher's observation, or (b) post-intervention improvements in neuropsychological performance. Secondary outcomes were risks of adverse events. Meta-analysis of nine eligible trials including 544 preschool children (mean age=4.86 years, female=11.98%, median treatment duration=4.33 weeks) supported the efficacy of psychostimulants against global symptoms from observations of parents (Hedges' g=0.6152, p<0.0001) and teachers (Hedges' g=0.6563, p=0.0039). Efficacy of psychostimulants was also noted against symptoms of inattention and hyperactivity/impulsivity, especially the latter (i.e., main symptoms in preschool children). Moreover, male gender, older age, and longer treatment duration were associated with better efficacy. Regarding adverse events, only the risk of poor appetite was higher in the psychostimulant group (odds ratio [OR]=2.39). However, the qualities of evidence were low to very low, indicating potential discrepancy between the true and estimated effect. Our results showed that psychostimulants might be beneficial for preschool children with ADHD, especially hyperactivity/impulsivity from teachers' observation, with tolerable side effects. Nevertheless, the true magnitude of the effect needs to be confirmed with more research due to low to very low certainty of the evidence.

Prenatal smoking, drinking, or caffeine does not affect ADHD symptoms in offspring

A recent study has found that in contrast to some previously published studies, maternal prenatal substance use with legal substances is not associated with offspring attention‐deficit hyperactivity disorder (ADHD). For the study, researchers measured associations between prenatal smoking, alcohol, and caffeine consumption with childhood ADHD symptoms. They took into consideration shared familial factors.

The Mediatory Role of Executive Functioning on the Association Between Sleep and Both Everyday Memory and ADHD Symptoms in Children and Youth With Down Syndrome.

People with Down syndrome (DS) commonly experience challenges with sleep, executive functioning, everyday memory, and symptoms of attention deficit hyperactivity disorder (ADHD). A path analysis was conducted to determine if executive function mediated the relationship between sleep problems and both everyday memory and ADHD symptoms. Parents of 96 children and youth with DS completed questionnaires related to sleep, executive functioning, everyday memory, and ADHD symptoms. Results showed that executive functioning fully mediated the relation between sleep and both everyday memory and ADHD symptoms. Implications for education and intervention for children and youth with DS are discussed.

Maternal use of substances while pregnant does not affect ADHD symptoms in offspring

A recent study has found that in contrast to some previously published studies, maternal prenatal substance use with legal substances is not associated with offspring attention‐deficit hyperactivity disorder (ADHD). For the study, researchers measured associations between prenatal smoking, alcohol, and caffeine consumption with childhood ADHD symptoms. They took into consideration shared familial factors.

The Impact of Maternal Depression on Internet-Parent–Child Interaction Therapy for Child Attention-Deficit/Hyperactivity Disorder: A Case Study

Conduct disorders and attention-deficit/hyperactivity disorder (ADHD) are highly comorbid, with an estimated prevalence rate of 51.5% for children between 2–17 years of age (Centers for Disease Control and Prevention, 2020). Parent–Child Interaction Therapy (PCIT) is an empirically supported behavioral parent training program for children with disruptive behavior. PCIT research consistently demonstrates decreases in disruptive behaviors and increases in positive parenting strategies among families of young children with ADHD; however, PCIT has yet to become widely recognized as a treatment for ADHD. This case study presents the treatment of a 6-year-old boy with ADHD and severe behavior problems. The case was further impacted by the single mother’s depressive symptoms and internet delivery of PCIT during the COVID-19 pandemic. Findings from this case report documented an improvement in disruptive child behaviors and emotion regulation and increased positivity during parent–child interactions, despite worsening maternal depressive symptoms. This case study highlights the utility of PCIT to improve child disruptive behaviors and ADHD symptoms in the midst of several complicating factors.

Relación entre los síntomas de déficit de atención/hiperactividad y el sueño en preescolares

IntroductionSleep problems are frequent in children with attention-deficit/hyperactivity disorder (ADHD). Some authors have tried to characterize paediatric sleep habits in Portugal, but none has focused on preschool-age children nor attempted to establish their association with ADHD. We aimed to assess the prevalence of ADHD symptoms in preschool-age children and to study their association with sleep habits. Material and methodsWe conducted a cross-sectional study. We distributed questionnaires to a random sample of caregivers of children enrolled in early childhood education centres in Porto. We collected data on sociodemographic characteristics, television watching and outdoor activities. We assessed ADHD symptoms and sleep habits with the Portuguese versions of the Conners’ Parents Rating Scale, Revised and the Children's Sleep Habits Questionnaire (CSHQ-PT), respectively. ResultsThe study included 381 preschoolers (50.90% male). We found high scores for ADHD symptoms in 13.10%, with a higher prevalence in girls (14.40% vs. 11.85%; P=.276). In the CSHQ-PT, 45.70% of participants had a mean total score greater than 48, which is the cut-off point applied in the screening of sleep disturbances in the Portuguese population. There was a significant association between high scores for ADHD symptoms and a lower maternal education level (P<.001), a shorter sleep duration (P=.049), and higher scores on parasomnias (P=.019) and sleep disordered breathing (P=.002) in CSHQ-PT subscales. ConclusionsADHD and sleep disorders are common in preschoolers, in Porto, and this study suggests some clinical correlations between them. Since these interactions are complex and far from being elucidated, further studies are paramount to provide guidance for prevention and managing strategies in younger children at risk for ADHD.