March 21, 2022
An international study team conducted the first meta-analysis of studies examining differences in time perception between persons with ADHD and normally developing controls. A systematic search of the peer-reviewed medical literature identified 55 studies that could be combined into various subgroups for meta-analysis.
A meta-analysis of 25 studies with a combined 1,633 participants looking at time discrimination found a medium effect size deficit among persons with ADHD in the number of correct comparisons between the length of two signals. There was little between-study heterogeneity and no sign of publication bias.
Turning to time estimation, a meta-analysis of eight studies with a combined 1,024 participants found a small-to-medium effect size increase in absolute errors (i.e., the absolute value of deviation between the specified and the estimated time interval, representing the absolute amount of error regardless of its direction) among persons with ADHD, compared to controls. Again, there was little between-study heterogeneity and no sign of publication bias.
A meta-analysis of seven studies with combined 380 participants looked at differences in time production, in which they had to produce a previously specified time interval by pressing and holding a button. In this case, those with ADHD manifested a small effect size increase in absolute error relative to their normally developing counterparts. There was moderate between-study heterogeneity and no sign of publication bias.
Finally, a meta-analysis of 26 studies with combined 2,364 participants examined differences in time reproduction, in which they had to reproduce the duration of a previously presented stimulus by pressing and holding a button. Here, those with ADHD exhibited a medium effect size increase in absolute error. There was moderate between-study heterogeneity and no indication of publication bias.
An acknowledged limitation of these meta-analyses was the inability to assess the effects of pharmacological treatment. In addition, 84% of the studies did not report the ethnicity of participants.
The team concluded, "We found meta-analytic evidence of significant deficits in individuals with ADHD across all timing paradigms ... individuals with ADHD have difficulties to discriminate stimuli that vary from each other for only several milliseconds, and they are more variable in their time estimates of several seconds irrespective of the paradigm examined, which may both be driven by their lowered alertness levels."
They suggested that this might eventually become a criterion to help diagnose ADHD: "Our findings have possible clinical implications, albeit not currently directly applicable to the clinical practice. As timing has been proposed as an independent neuropsychological pathway to ADHD, timing tasks should be considered in the clinical assessment of ADHD to better characterize the clinical profile of the patient... To characterize further the phenotype of the patient during the diagnostic process that may deserve clinical attention, we suggest developing a tool based on the time estimation paradigm. The time estimation accuracy score not only represents an intuitive score reflecting faster internal clock mechanisms in individuals with ADHD, but the paradigm also shows high internal consistency and test-retest reliability, allowing for a reliable assessment of developmental or interventional changes in timing abilities related to developmental factors or external interventions."
Ivo Marx, Samuele Cortese, Michael G Koelch, Thomas Hacker, "Meta-analysis: Altered Perceptual Timing Abilities in Attention-Deficit/Hyperactivity Disorder," Journal of the American Academy of Child and Adolescent Psychiatry (2021), published online,https://doi.org/10.1016/j.jaac.2021.12.004.
.png)
A recent study from Istanbul sheds light on how psychiatric admissions and diagnoses changed during the first few months of the pandemic compared to previous periods, offering critical insights for parents, clinicians, and policymakers.
This study, conducted by a team of researchers led by Ozalp Ekinci, examined psychiatric admissions among children and adolescents during 2019 and 2020.
By looking at diagnosis rates for various psychiatric conditions, the researchers aimed to pinpoint shifts in the mental health landscape as a direct response to the pandemic.
The analysis revealed several notable trends in psychiatric diagnoses among children and adolescents:
This study’s findings highlight some key takeaways that can guide mental health support efforts for children and adolescents:
As we continue to see the effects of the COVID-19 pandemic on mental health, studies like this one serve as important reminders of the unique mental health needs of young people. Supporting children and adolescents through proactive and targeted mental health services—especially during times of crisis—will be crucial to fostering resilience and well-being in future generations.
Adult ADHD has long been a subject of debate in the field of mental health, with previous estimates of its prevalence varying widely. To achieve a more precise understanding, an international team of researchers conducted a new umbrella review and meta-analysis, offering an updated estimate of adult ADHD rates worldwide.
This large-scale analysis combined five systematic reviews and meta-analyses, incorporating data from 57 unique primary studies. Altogether, the research synthesized findings from a pooled total of over 21 million participants. This comprehensive approach provided a more accurate estimate of the global prevalence of ADHD in adults.
The study concluded that the worldwide prevalence of adult ADHD is 3.1%, with a 95% confidence interval ranging from 2.6% to 3.6%. This estimate falls within the range of earlier reports but provides a more targeted understanding of the rate at which ADHD affects adults globally.
The researchers described this prevalence rate as “relatively high.” They noted that it is only slightly lower than the estimated prevalence of major mental health conditions like schizophrenia (4%) and major depressive disorder (5%)—disorders that have historically received significant attention and resources worldwide.
Moreover, the prevalence of adult ADHD is higher than that of several other well-known mental health conditions, including bipolar disorder (1%), as well as anxiety disorders such as PTSD (Post-Traumatic Stress Disorder), OCD (Obsessive-Compulsive Disorder), GAD (Generalized Anxiety Disorder), and panic disorders.
This updated estimate emphasizes that ADHD is a significant global mental health concern in adults, comparable to or exceeding the prevalence of other disorders that are often more widely recognized. These findings underscore the need for greater awareness, research, and treatment options for adult ADHD, which is still frequently misunderstood or overlooked in the broader discourse of mental health.
By providing a clearer picture of how prevalent ADHD is in adult populations around the world, this study contributes valuable data that could shape future research, policy, and clinical approaches.
Attention-Deficit/Hyperactivity Disorder (ADHD) remains a prevalent condition among children and adolescents in the United States. A recent analysis based on the National Health Interview Survey (NHIS), conducted by the National Center for Health Statistics at the CDC, provides an updated look at ADHD prevalence from 2018 to 2021. Here’s a closer look at what the data reveals.
The NHIS is an annual survey primarily conducted through face-to-face interviews in respondents’ homes. Telephone interviews are used as a substitute in cases where travel is impractical. For each family interviewed, one child aged 3-17 is randomly selected for the survey through a computer program. Over the four years studied (2018-2021), a total of 26,422 households with children or adolescents participated.
The analysis found that 9.5% of children and adolescents in the United States had been diagnosed with ADHD, based on reports from family members. However, the prevalence varied significantly with age:
The increase in ADHD diagnosis with age underscores the importance of monitoring children’s developmental needs as they progress through school and adolescence.
The survey revealed a notable difference in ADHD prevalence between genders, with 12.4% of males diagnosed compared to 6.6% of females—nearly a two-to-one gap. This aligns with previous research indicating that ADHD is more frequently diagnosed in boys than girls, though awareness of how ADHD presents differently across genders is growing.
Family income played a significant role in ADHD prevalence, particularly among lower-income groups:
This pattern suggests that socioeconomic factors might influence the diagnosis and management of ADHD, with lower-income families possibly experiencing greater barriers to early diagnosis or consistent treatment.
Geographic location also impacted ADHD rates. Prevalence was highest in the South (11.3%), followed by the Midwest (10%), the Northeast (9.1%), and significantly lower in the West (6.9%). These variations could reflect regional differences in healthcare access, diagnostic practices, or cultural attitudes towards ADHD.
Despite these variations in demographics, the overall prevalence of ADHD remained relatively stable across the study period from 2018 to 2021, showing no significant changes by year.
The findings from this updated analysis provide a clearer picture of ADHD’s prevalence across different demographic groups in the United States. They highlight the need for tailored approaches to diagnosis and care, taking into account factors like age, gender, income, and geographic location. With ADHD being a common condition affecting nearly 1 in 10 children, ongoing research and support for families are crucial to ensure that those with ADHD receive the care and resources they need.
This study reinforces the importance of awareness and early intervention, especially for families in underserved regions or those facing economic challenges. As clinicians and educators continue to support children with ADHD, understanding these demographic trends can help in creating more equitable access to diagnosis and treatment.
_logo%201.svg)
