Latent class analysis (LCA) is a statistical procedure used to identify qualitatively different subgroups within populations who often share certain outward characteristics. The assumption underlying ...LCA is that membership in unobserved groups (or classes) can be explained by patterns of scores across survey questions, assessment indicators, or scales. The application of LCA is an active area of research and continues to evolve. As more researchers begin to apply the approach, detailed information on key considerations in conducting LCA is needed. In the present article, we describe LCA, review key elements to consider when conducting LCA, and provide an example of its application.
Impulsivity has a strong genetic component and is considered an endophenotype in many psychiatric disorders. Impulsivity in adult ADHD has become a focus of interest more recently because of its ...suggested prominence in this age. Objective: This study aimed to access self-reported impulsivity levels in biological parents of ADHD offspring, according to their status: non-ADHD (controls), remitted, nonremitted. Method: Impulsivity levels of 155 parents of ADHD children were compared according to their status using the Barratt Impulsiveness Scale (BIS-11). Results: The ADHD group presented the highest levels of impulsivity compared with all other groups. The remitted ADHD and control groups showed no significant differences in impulsivity levels. Conclusion: Impulsivity tended to remit alongside ADHD symptoms in remitters and to persist in those presenting with the residual form of adult ADHD suggesting it should not be considered as an endophenotype. Only the attentional dimension was impaired, cautioning against Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) impulsivity proposed criteria.
In the last two decades, there has been a growing body of research that identified sex-related differences in attention-deficit hyperactivity disorder (ADHD). Our objective was to quantify whether ...these sex differences are based on altered functional brain connectivity profiles. In addition, we investigated whether the presence of comorbid disorders, including depression, substance use disorder (SUD) and overweight, influenced these sex differences. A seed-based connectivity analysis of the external globus pallidus (GPe), an important inhibitory relay hub of the fronto-thalamo-striatal-loop, was performed. In a first step, we searched for sex-related differences in ADHD patients (
N
= 137) and separately in healthy controls (HC) (
N
= 45), after that, we compared an equal group of HC and ADHD patients to compare sex-related differences in ADHD patients and HC. In a second step, we studied whether the neural basis of comorbidity patterns is different between male and female patients. We observed that male ADHD patients demonstrated a decrease in functional connectivity (FC) from the GPe to the left middle temporal gyrus compared to female ADHD patients. Moreover, within the full ADHD group (
N
= 137), there was a lower FC in male patients from GPe to the right frontal pole/middle frontal gyrus compared to female patients. Male ADHD patients with depression demonstrated decreased FC from the GPe to parts of the occipital cortex compared to female ADHD patients with depression. No such effect was demonstrated for overweight or SUD. The current study reveals different FC profiles in males and females with ADHD, which are centered around altered connectivity with the GPe. An improved understanding of sex-differences in ADHD, and the role of comorbid disorders, therein can result in improved diagnostic and therapeutic opportunities for ADHD patients.
Attention deficit/hyperactivity disorder (ADHD) is characterized as a neurodevelopmental disorder. However, data from several recent studies suggest that there may be adults who meet current criteria ...for ADHD, yet did not experience symptoms until adulthood (i.e., “adult-onset ADHD”). This systematic review evaluated and synthesized the empirical evidence on adult-onset ADHD to answer the question:
Is the extant literature strong enough to evaluate adult-onset ADHD?
Nine studies met strict inclusion/exclusion criteria. Results suggest that the methodologies of the extant studies were not strong enough to evaluate adult-onset ADHD. Insufficient methodologies provide presently unclear information about the nature of late-onset symptoms. These symptoms seem to exist but their source could be (1) adult-emergent symptoms that were previously surpassed due to lower environmental demands/supportive facilitators, (2) mimics that were not properly assessed, or (3) childhood-onset symptoms that were not detected earlier due to failure to come to clinical attention. Future directions, clinical recommendations, and limitations of the literature and the current review are discussed.
Executive dysfunction has been shown to be a promising endophenotype in neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD). This ...article reviewed 26 studies that examined executive function comparing ASD and/or ADHD children. In light of findings from this review, the ASD + ADHD group appears to share impairment in both flexibility and planning with the ASD group, while it shares the response inhibition deficit with the ADHD group. Conversely, deficit in attention, working memory, preparatory processes, fluency, and concept formation does not appear to be distinctive in discriminating from ASD, ADHD, or ASD + ADHD group. On the basis of neurocognitive endophenotype, the common co-occurrence of executive function deficits seems to reflect an additive comorbidity, rather than a separate condition with distinct impairments.
The Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale (SWAN) measures the full spectrum of attention and activity symptoms, not just the negative end of the distribution. Previous ...studies revealed strong psychometric properties of the parent and teacher report versions; however, there is little research on the new self-report form of the SWAN. Therefore, our research aimed to explore the psychometric characteristics of the SWAN self-report. A non-clinical sample of young women ( N = 664, mean age: 20.01 years, SD : 3.08 years) completed the SWAN self-report, the Strengths and Difficulties Questionnaire (SDQ) and the Mental Health Continuum Short Form (MHC-SF). We tested several models using confirmatory factor analyses to assess the factorial validity of the SWAN self-report. Distributional characteristics, convergent, and predictive validity were assessed. A bifactor model with a general factor and a specific inattention factor (bifactor-1) provided the best fit in our data (CFI = 0.977, TLI/NFI = 0.972, RMSEA = 0.053 90% CI: 0.047 – 0.059, SRMR = 0.061, ω = 0.90). The reliability of the general ADHD factor was good (ω h = 0.87), and the specific inattention factor was acceptable (ω h = 0.73). The distribution of the SWAN self-report scores did not differ from the normal distribution. A strong correlation between the SWAN and the SDQ Hyperactivity subscale was found. The analyses revealed good predictive validity. Our results suggest that the SWAN self-report is a valuable tool for assessing symptoms of ADHD in adolescents and young adults.
Environmental lead exposure has been a much-discussed risk factor for the development of ADHD for decades. However, due to methodological shortcomings, the existing research on this topic is highly ...inconsistent. We will attempt to clarify this question by performing a meta-analysis based on a systematic literature search until February 2024 including different databases such as Pubmed and Google Scholar. The effects of environmental lead exposure were synthesized by odds ratios. A random effects model was deployed with a Paule-Mandel estimator using Hedges' invariance weighting. In addition, we carried out sensitivity analyses to examine the robustness of effects, including the detection of outliers, publication bias, p-hacking and moderating variables. In total, 14 studies with 14 effect sizes were included which had investigated the effects of lead exposure on the development of ADHD. The analyses were based on a final sample size of N = 7618 with n = 2554 ADHD cases (33,53 %) and n = 5064 healthy controls (66.47 %). Our results show that lead exposure was significantly associated with a higher risk of ADHD development. Regression analyses demonstrated that increased age of participants and increased lead significantly enhanced the risk of ADHD. Summing up we present novel results concerning the relationship between environmental lead exposure and the development of ADHD, while discussing underlying pathomechanisms as well as limitations. Finally, we provide recommendations for future studies and public health policies.
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•Previous studies show the neurotoxic effects of lead, influencing neuronal development.•ADHD development in children/adolescents is associated with environmental lead exposure.•We found a significant relationship between age-adjusted blood lead levels and risk of ADHD.•Increased lead exposure and increased participant age result in a higher risk of ADHD.
Attention deficit hyperactivity disorder (ADHD) is a common pediatric neurodevelopmental disorder. The core symptoms include a functionally significant level of inattentiveness and distractibility. ...The aim of the present study is to detect the abnormalities in clinical andpolysomnography (PSG) studies in children with ADHD. It aims at finding the relation between ADHD symptoms severity and results of sleep studies, and exploring the correlations between them.
The study included 40 ADHD patients and 40 healthy control children. All patients and controls were subjected to history taking, clinical examination, psychaitric assessment, and then to electrophysiological studies including overnight long-term electroencephalography (EEG) and PSG. Results: EEG results showed increased theta activity, central sharp waves and generalized spikes, sharp and slow waves. PSG studies revealed statistically significant increased nocturnal movements and greater night-to-night variability in sleep patterns among children with ADHD, with otherwise inconsistent differences in sleep architecture between children with and without ADHD. Discussion: Some of our results came in agreement with other simulating researches, however, video monitoring may be used in future studies to detect any subtle events.
ADHD is frequently associated with sleep-disordered breathing and limb movement disorder.
EEG abnormalities and sleep abnormalities can play a role in the etiology or even accentuation of ADHD. Aiming at their treatment can ameliorate the symptoms of the disease.
Autism and attention deficit hyperactivity disorder (ADHD) are heterogeneous neurodevelopmental conditions with complex underlying neurobiology that is still poorly understood. Despite overlapping ...presentation and sex-biased prevalence, autism and ADHD are rarely studied together, and sex differences are often overlooked. Population modelling, often referred to as normative modelling, provides a unified framework for studying age-specific and sex-specific divergences in brain development.
Here we used population modelling and a large, multi-site neuroimaging dataset (N = 4255 after quality control) to characterise cortical anatomy associated with autism and ADHD, benchmarked against models of average brain development based on a sample of over 75,000 individuals. We also examined sex and age differences, relationship with autistic traits, and explored the co-occurrence of autism and ADHD (autism+ADHD).
We observed robust neuroanatomical signatures of both autism and ADHD. Overall, autistic individuals showed greater cortical thickness and volume, that was localised to the superior temporal cortex, whereas individuals with ADHD showed more global increases in cortical thickness, but lower cortical volume and surface area across much of the cortex. The autism+ADHD group displayed a unique pattern of widespread increases in cortical thickness, and certain decreases in surface area. We also found evidence that sex modulates the neuroanatomy of autism but not ADHD, and an age-by-diagnosis interaction for ADHD only.
These results indicate distinct cortical differences in autism and ADHD that are differentially impacted by age, sex, and potentially unique patterns related to their co-occurrence.
The histamine H3 receptor is a favourable target for the treatment of cognitive deficits. Here we report the in vitro and in vivo profile of RGH-235, a new potent, selective, and orally active H3 ...receptor antagonist/inverse agonist developed by Gedeon Richter Plc. Radioligand binding and functional assays were used for in vitro profiling. Procognitive efficacy was investigated in rodent cognitive tests, in models of attention deficit hyperactive disorder (ADHD) and in cognitive tests of high translational value (rat touch screen visual discrimination test, primate fixed-foreperiod visual reaction time task). Results were supported by pharmacokinetic studies, neurotransmitter release, sleep EEG and dipsogenia. RGH-235 displayed high affinity to H3 receptors (Ki = 3.0–9.2 nM, depending on species), without affinity to H1, H2 or H4 receptors and >100 other targets. RGH-235 was an inverse agonist (35S GTPγS binding) and antagonist (pERK1/2 ELISA), showing favourable kinetics, inhibition of the imetit-induced dipsogenia and moderate effects on sleep-wake EEG. RGH-235 stimulated neurotransmitter release both in vitro and in vivo. RGH-235 was active in spontaneously hypertensive rats (SHR), generally considered as a model of ADHD, and revealed a robust pro-cognitive profile both in rodent and primate tests (in 0.3–1 mg/kg) and in models of high translational value (e.g. in a rodent touch screen test and in non-human primates). The multiple and convergent procognitive effects of RGH-235 support the view that beneficial cognitive effects can be linked to antagonism/inverse agonism of H3 receptors.
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