January 10, 2022

How effective and safe is transcranial direct current stimulation for treating ADHD?

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:

  •  Working memory was improved by anodal stimulation - but not cathodal stimulation - of the left dorsolateral prefrontal cortex. Anodal stimulation of the right inferior frontal gyrus had no effect.
  •  Response inhibition: Anodal stimulation of the left or right dorsolateral prefrontal cortex was more effective than anodal stimulation of the bilateral prefrontal cortex.
  • Motivational and emotional processing was improved only with stimulation of both the dorsolateral prefrontal cortex and orbitofrontal cortex.

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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South Korean Population Study Finds Child ADHD Impacts Maternal, but Not Paternal, Mental Health

Given the persistence of ADHD and its adverse effects on children and adolescents, one might expect caregivers to face greater parenting challenges, with potential effects on their own mental health. 

To what extent do parenting stress, depression, and – at the extreme – even suicidal ideation manifest themselves among caregivers of ADHD patients as opposed to caregivers of children and adolescents without ADHD? 

A pair of Korean researchers made use of their country’s single-payer health insurance system, which maintains records on virtually the entire population, to perform a nationwide population study. They used data from the Korean National Health and Nutrition Examination Surveys (KNHANES) covering the decade from 2011 to 2020. KNHANES is an annual survey using a sophisticated sampling design conducted by the Korean Ministry of Health and Welfare to represent the entire population of South Korea. 

The analysis included 14,428 individuals who had children younger than 19 at the time of participation. All were asked whether their child had ever been diagnosed with ADHD by a physician. The mental health problems of the parents were assessed in terms of perceived stress, depressive symptoms, and suicidality. 

Of the 14,428 participants, 8,298 (57.5 %) were mothers and 6,130 (42.5 %) were fathers. Of the mothers, 116 (1.4 %) had a child with ADHD, and of the fathers, 86 (1.4 %) had a child with ADHD. 

The researchers adjusted for the following confounders: age of caregiver, education level, household income, area of residence, employment status, alcohol consumption, smoking status, cohabitation status, number of children, and child’s age. 

After adjustment, mothers of ADHD patients fared significantly worse than mothers of typically developing children on all three categories of mental health problems. They were 67% more likely to report higher stress, three times as likely to report symptoms of depression, and 2.5 times more likely to report suicidal ideation.  

Yet that pattern did not carry over to fathers, where there was no significant difference in mental health indicators between fathers of children with ADHD and fathers of children without ADHD. 

The authors concluded, “Parents of children with ADHD, especially mothers, need community support and public health attention to help alleviate their mental health problems.” 

 

February 19, 2025

South Korean Nationwide Population Study Finds ADHD Diagnosis Associated With Greater Odds of Subsequent Diagnosis of Major Psychiatric Disorders

Background: 

ADHD is commonly accompanied by psychiatric comorbidities that complicate its diagnosis and treatment. Roughly two out of three affected children and adolescents have one or more comorbid psychiatric disorder. 

Because the peak age of ADHD onset is typically a decade or more earlier than those for schizophrenia, depressive disorder, or bipolar disorder, it is essential to explore these comorbidities over an extended period. Populations studies help researchers identify broader patterns and trends within an entire population and includes adults as well as children. This type of study provides unique insights into the population at large, rather than a sample group.

In earlier studies the maximum follow-up period was twelve years, insufficient in view of the roughly ten years between onset of ADHD and onset of major psychiatric disorders. Also, previous nationwide population studies have included less than 150,000 participants. 

The Study:

This study, relying on data from South Korea’s universal single-payer health insurance system, included over one and a half million individuals. Persons previously diagnosed with depression, bipolar disorder, tic disorder, or schizophrenia were excluded. 

382,434 individuals had been diagnosed with ADHD, while 1,169,279 were without an ADHD diagnosis.  

Propensity score matching ensured that potential confounders, both sociodemographic and clinical, were equalized for the ADHD and control groups. After matching, there were 353,898 individuals in each group. 

After these adjustments, individuals in the ADHD group were at least an order of magnitude more likely to subsequently be diagnosed with  psychiatric disorders than their peers without an ADHD diagnosis: 

  • Almost eleven times more likely to be diagnosed with depressive disorder. 
  • More than twelve times as likely to be diagnosed with bipolar disorder. 
  • Over thirteen times more likely to be diagnosed with schizophrenia. 

Conclusion:

The Korean study team concluded, “Overall, our findings suggest that upon prolonged examination, the risk of subsequent diagnoses of other psychiatric disorders in individuals with ADHD appears to be higher than that reported previously. … Therefore, patients with ADHD should be carefully screened for the presence of other psychiatric symptoms on a regular basis from an earlier age … It is advisable to have a follow-up period extending beyond 10 years to sufficiently identify the occurrence of comorbid disorders in patients with ADHD.” 

February 18, 2025

NEWS STUDY: Focus Group Study of Primary Teachers' Perceptions of Children with ADHD who Struggle Socially

Children with ADHD often face challenges in social interactions, leading to long-term consequences if not properly addressed. While various interventions exist, many fail to consider the broader social context in which these children interact. A recent study conducted in Bergen, Norway, explored how primary school teachers perceive their role in supporting children with ADHD who struggle socially and the strategies they use to assist them.

Investigating Teacher Perspectives

Researchers conducted semi-structured interviews with five focus groups of primary school teachers. Using reflexive thematic analysis, they identified two major themes:

  1. Understanding Individual Needs in Context – Teachers emphasized that every child is unique, and ADHD should not define a student's social struggles. They highlighted the importance of considering the child’s specific social challenges within their broader environment.
  2. Adapting Strategies Through Continuous Assessment – Teachers described their work as a dynamic and flexible process, adjusting their approaches based on the child's evolving needs. This included providing subtle background support as well as direct guidance in social interactions.
A Personalized Approach to Social Support

Rather than relying on standardized interventions, teachers tailored their strategies to foster an inclusive and supportive social environment. Their methods included both active participation in social situations and behind-the-scenes efforts to encourage peer inclusion and understanding.

Rethinking ADHD and Social Development

This study underscores the need to move beyond labels and recognize children with ADHD as individuals with distinct social needs. Teachers play a crucial role in shaping these children’s experiences, using flexible and personalized approaches to promote positive social interactions. By integrating social context and individualized support, educators can help children with ADHD build meaningful connections and navigate their social world more effectively.

February 12, 2025