January 10, 2022
ADHD is hypothesized to arise from 1) poor inhibitory control resulting from impaired executive functions which are associated with reduced activation in the dorsolateral prefrontal cortex and increased activation of some subcortical regions; and 2)hyperarousal to environmental stimuli, hampering the ability of the executive functioning system, particularly the medial frontal cortex, orbital and ventromedial prefrontal areas, and subcortical regions such as the caudate nucleus, amygdala, nucleus accumbens, and thalamus, to control the respective stimuli.
These brain anomalies, rendered visible through magnetic resonance imaging, have led researchers to try new means of treatment to directly address the deficits. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that uses a weak electrical current to stimulate specific regions of the brain.
Efficacy:
A team of researchers from Europe and ran performed a systematic search of the literature and identified fourteen studies exploring the safety and efficacy of tDCS. Three of these studies examined the effects on ADHD symptoms. They found a large effect size for the inattention subscale and a medium effect size for the hyperactivity/impulsivity. Yet, as the authors cautioned, "a definite conclusion concerning the clinical efficacy of tDCS based on the results of these three studies is not possible."
The remaining studies investigated the effects on specific neuropsychological and cognitive deficits in ADHD:
The fact that heterogeneity in the methodology of these studies made meta-analysis impossible means these results, while promising, cannot be seen as in any way definitive.
Safety:
Ten studies examined childhood ADHD. Three found no adverse effects either during or after tDCS. One study reported a feeling of "shock" in a few patients during tDCS. Several more reported skin tingling and itching during tDCS. Several also reported mild headaches.
The four studies of adults with ADHD reported no major adverse events. One study reported a single incident of acute mood change, sadness, diminished motivation, and tension five hours after stimulation. Another reported mild instances of skin tingling and burning sensations.
To address side effects such as tingling and itching, the authors suggested reducing the intensity of the electrical current and increasing the duration. They also suggested placing electrodes at least 6 cm apart to reduce current shunting through the ski. For children, they recommended the use of smaller electrodes for better focus in smaller brains.
The authors concluded, "The findings of this systematic review suggest at least a partial improvement of symptoms and cognitive deficits in ADHD by tDCS. They further suggest that stimulation parameters such as polarity and site are relevant to the efficacy of tDCS in ADHD. Compared to cathodal stimulation, Anodal tDCS seems to have a superior effect on both the clinical symptoms and cognitive deficits. However, the routine clinical application of this method as an efficient therapeutic intervention cannot yet be recommended based on these studies ..."
Mohammad AliSalehinejad, Vahid Nejati, Mohsen Mosayebi-Samani, Ali Mohammadi, MilesWischnewski, Min-Fang Kuo, AllesioAvenanti, Carmelo M. Vicario & Michael A.Nitsche, "Transcranial Direct Current Stimulation in ADHD: A Systematic Reviewof Efficacy, Safety, and Protocol-induced Electrical Field Modeling Results," NeuroscienceBulletin(2020),https://doi.org/10.1007/s12264-020-00501-x.
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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.
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