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October 31, 2025
Background:
Pharmacotherapies, such as methylphenidate, are highly effective for short-term ADHD management, but issues remain with medication tolerability and adherence. Some patients experience unwanted side effects from stimulant medications, leaving them searching for alternative ADHD treatments. Alternative treatments such as cognitive training, behavioral therapies, psychological interventions, neurofeedback, and dietary changes have, so far, shown limited success. Thus, there is a critical need for non-pharmacological options that boost neurocognitive performance and address core ADHD symptoms.
First— What Are NIBS (Non-Invasive Brain Stimulation) Techniques?
Non-invasive brain stimulation (NIBS) techniques, including transcranial direct current stimulation (tDCS), transcranial random noise stimulation (tRNS), transcranial alternating current stimulation (tACS), and repetitive transcranial magnetic stimulation (rTMS) are generating growing attention within the scientific community.
NIBS techniques are methods that use external stimulation, such as magnets or electrical currents, to affect brain activity without any invasive procedures. In transcranial alternating current stimulation (tACS), for example, small electrodes are placed on the scalp of the patient, and a weak electrical current is administered.
The theory behind these techniques is that when a direct current is applied between two or more electrodes placed on specific areas of the head, it makes certain neurons more or less likely to fire. This technique has been successfully used to treat conditions like depression and anxiety, and to aid recovery from stroke or brain injury.
The Study:
Previous meta-analyses have produced conflicting indications of efficacy. A Chinese research team consisting of sports and rehabilitative medicine professionals has just published a network meta-analysis to explore this further, through direct comparison of five critical outcome domains: inhibitory control, working memory, cognitive flexibility, inattention, hyperactivity and impulsivity.
To be included, randomized controlled trials needed to have participants diagnosed with ADHD, use sham control groups, and assess ADHD symptoms and executive functions – such as inhibitory control, working memory, cognitive flexibility, inattention, hyperactivity, and impulsivity – using standardized tests.
A total of thirty-seven studies encompassing 1,615 participants satisfied the inclusion criteria. It is worth noting, however, that the authors did not specify the number of randomized controlled trials nor the number of participants included in each arm of the network meta-analysis.
Furthermore, the team stated, “We checked for potential small study effects and publication bias by conducting comparison-adjusted funnel plots,” but did not share their findings. They also did not provide information on outcome variation (heterogeneity) among the RCTs.
Results:
Ultimately, none of the interventions produced significant improvements in ADHD symptoms, whether in inattention symptoms or hyperactivity/impulsivity symptoms. Likewise, none of the interventions produced significant improvements in inhibitory control. Some tDCS interventions enhanced working memory and cognitive flexibility, but details about trial numbers and participants were missing. The team concluded, “none of the NIBS interventions significantly improved inhibitory control compared to sham controls. … In terms of working memory, anodal tDCS over the left DLPFC plus cathodal tDCS over the right DLPFC … and anodal tDCS over the right inferior frontal cortex (rIFC) plus cathodal tDCS over the right supraorbital area ... were associated with significant improvements compared to sham stimulation. For cognitive flexibility, only anodal tDCS over the left DLPFC plus cathodal tDCS over the right supraorbital area demonstrated a statistically significant benefit relative to sham. ... Compared to the sham controls, none of the NIBS interventions significantly improved inattention. ... Compared to the sham controls, none of the NIBS interventions significantly improved hyperactivity and impulsivity.”
How Should We Interpret These Results?
In a word, skeptically.
If one were to read just the study’s abstract, which states, “The dual-tDCS and a-tDCS may be considered among the preferred NIBS interventions for improving cognitive function in ADHD”, it might seem that the takeaway from this study is that this combination of brain stimulation techniques might be a viable treatment option for those with ADHD. Upon closer inspection, however, the results do not suggest that any of these methods significantly improve ADHD symptoms. Additionally, this study suffers from quite a few methodological flaws, so any results should be viewed critically.
Xinwen Liang, Xiaoyu Wei, Yan Huang, Jing Li, Huan Feng, Jingyuan Fan, Longguo Zhang,
Zhijiang Wang, Xin Zhao, Weimin Pan, and Rui Liu, “Comparative efficacy of non-invasive
brain stimulation for attention-deficit/hyperactivity disorder: a systematic review and network
meta-analysis,” Frontiers in Neurology (2025), https://doi.org/10.3389/fneur.2025.1650154
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 ..."
It sounds like science fiction, but scientists have been testing computerized methods to train the brains of ADHD people to reduce both ADHD symptoms and cognitive deficits such as difficulties with memory or attention.
Two main approaches have been used: cognitive training and neurofeedback. Cognitive training methods ask patients to practice tasks aimed at teaching specific skills, such as retaining information in memory or inhibiting impulsive responses.
Currently, results from ADHD brain studies suggest that the ADHD brain is not very different from the non-ADHD brain, but that ADHD leads to small differences in the structure, organization, and functioning of the brain. The idea behind cognitive training is that the brain can be reorganized to accomplish tasks through a structured learning process. Cognitive retraining helps people who have suffered brain damage, so it was logical to think it might help the types of brain differences seen in ADHD people. Several software packages have been created to deliver cognitive training sessions to ADHD people.
Neurofeedback was applied to ADHD after it had been observed, in many studies, that people with ADHD have unusual brain waves as measured by the electroencephalogram (EEG). We believe that these unusual brain waves are caused by the different ways that the ADHD brain processes information. Because these differences lead to problems with memory, attention, inhibiting responses, and other areas of cognition and behavior, it was believed that normalizing the brain waves might reduce ADHD symptoms.
In a neurofeedback session, patients sit with a computer that reads their brain waves via wires connected to their heads. The patient is asked to do a task on the computer that is known to produce a specific type of brain wave. The computer gives feedback via sound or a visual on the computer screen that tells the patient how 'normal' their brainwaves are. By modifying their behavior, patients learn to change their brain waves. The method is called neurofeedback because it gives patients direct feedback about how their brains are processing information.
Both cognitive training and neurofeedback have been extensively studied. If you've been reading my blogs about ADHD, you know that I play by the rules of evidence-based medicine. My view is that the only way to be sure that a treatment works is to see what researchers have published in scientific journals. The highest level of evidence is a meta-analysis of randomized controlled clinical trials. This ensures that many rigorous studies have been conducted and summarized with a sophisticated mathematical method.
Although both cognitive training and neurofeedback are rational methods based on good science, meta-analyses suggest that they do not help reduce ADHD symptoms. They may be helpful for specific problems, such as problems with memory, but more work is needed to be certain if that is true. The future may bring better news about these methods if they are modified and become more effective. You can learn more about non-pharmacologic treatment for ADHD from a book I recently edited: Faraone, S. V. &Antshel, K. M. (2014). ADHD: Non-Pharmacologic Interventions. Child Adolesc Psychiatr Clin N Am 23, xiii-xiv.
Noting that "despite a lack of solid evidence for their use, rTMS [repetitive transcranial magnetic stimulation]and tDCS [transcranial direct current stimulation] are already offered clinically and commercially in ADHD," and that a recent meta-analysis of ten tDCS studies found small but significant improvements in outcomes, but had several methodological shortcomings and did not include two studies reporting mostly null effects, a team of British neurologists performed a meta-analysis of all twelve sham-controlled, non-open-label, studies found in a comprehensive search of the peer-reviewed literature.
Ten of the twelve randomized-controlled trials used anodal stimulation of the dorsolateral prefrontal cortex, while the other two used anodal stimulation of the right inferior frontal cortex.
The trials explored several measures of cognition. The research team carried out a meta-analysis of all twelve trials, with a total of 232 participants, and found no significant improvement in attention scores from CDC, relative to sham stimulation. A second meta-analysis, of eleven trials with a total of 220 participants, assessed the efficacy of tDCS on improving inhibition scores, and again found no significant effect. A third meta-analysis, encompassing eight trials with a total of 124 participants, evaluated the efficacy of tDCS on improving processing speed scores, once again finding no significant effect.
The latter two meta-analyses approached the border of significance, prompting the authors to speculate that larger sample sizes could bring the results just over the threshold of significance. Even so, effect sizes would be small.
It is also possible that the trials focused on regions of the brain suboptimal for this objective, and thus the authors "cannot rule out the possibility that stimulation of other prefrontal regions (such as the right hemispheric inferior frontal cortex or dorsolateral prefrontal cortex or parietal regions), multiple session tDCS or tDCS in combination with cognitive training could improve clinically or cognitive functions in ADHD."
As to concerns about safety, on the other hand, "stimulation was well-tolerated overall."
The authors concluded that based on current evidence, tDCS of the dorsolateral prefrontal cortex cannot yet be recommended as an alternative Neurotherapy for ADHD.
Background:
Sleep is more than simple rest. When discussing sleep, we tend to focus on the quantity rather than the quality, how many hours of sleep we get versus the quality or depth of sleep. Duration is an important part of the picture, but understanding the stages of sleep and how certain mental health disorders affect those stages is a crucial part of the discussion.
Sleep is an active mental process where the brain goes through distinct phases of complex electrical rhythms. These phases can be broken down into non-rapid eye movement (NREM) and rapid eye movement (REM). The non-rapid eye movement phase consists of three stages of the four stages of sleep, referred to as N1, N2(light sleep), and N3(deep sleep). N4 is the REM phase, during which time vivid dreaming typically occurs.
Two of the most important measurable brain rhythms occur during non-rapid eye movement (NREM) sleep. These electrical rhythms are referred to as slow waves and sleep spindles. Slow waves reflect deep, restorative sleep, while spindles are brief bursts of brain activity that support memory and learning.
The Study:
A new research review has compiled data on how these sleep oscillations differ across psychiatric conditions. The findings suggest that subtle changes in nightly brain rhythms may hold important clues about a range of disorders, from ADHD to schizophrenia.
The Results:
People with ADHD showed increased slow-spindle activity, meaning those brief bursts of NREM activity were more frequent or stronger than in people without ADHD. Why this happens isn’t fully understood, but it may reflect differences in how the ADHD brain organizes information during sleep. Evidence for slow-wave abnormalities was mixed, suggesting that deep sleep disruption is not a consistent hallmark of ADHD.
Among individuals with autism spectrum disorder (ASD), results were less consistent. However, some studies pointed to lower “spindle chirp” (the subtle shift in spindle frequency over time) and reduced slow-wave amplitude. Lower amplitude suggests that the brain’s deep-sleep signals may be weaker or less synchronized. Researchers are still working to understand how these patterns relate to sensory processing, learning differences, or daytime behavior.
People with depression tended to show reduced slow-wave activity and fewer or weaker sleep spindles, but this pattern appeared most strongly in patients taking antidepressant medications. Since antidepressants can influence sleep architecture, researchers are careful not to overinterpret the changes. Nevertheless, these changes raise interesting questions about how both depression and its treatments shape the sleeping brain.
In post-traumatic stress disorder (PTSD), the trend moved in the opposite direction. Patients showed higher spindle frequency and activity, and these changes were linked to symptom severity which suggests that the brain may be “overactive” during sleep in ways that relate to hyperarousal or intrusive memories. This strengthens the idea that sleep physiology plays a role in how traumatic memories are processed.
The clearest and most reliable findings emerged in psychotic disorders, including schizophrenia. Across multiple studies, individuals showed: Lower spindle density (fewer spindles overall), reduced spindle amplitude and duration, correlations with symptom severity, and cognitive deficits.
Lower slow-wave activity also appeared, especially in the early phases of illness. These results echo earlier research suggesting that sleep spindles, which are generated by thalamocortical circuits, might offer a window into the neural disruptions that underlie psychosis.
The Take-Away:
The review concludes with a key message: While sleep disturbances are clearly present across psychiatric conditions, the field needs larger, better-standardized, and more longitudinal studies. With more consistent methods and longer follow-ups, researchers may be able to determine whether these oscillations can serve as reliable biomarkers or future treatment targets.
For now, the take-home message is that the effects of these mental health disorders on sleep are real and measurable.
Many studies have shown that ADHD is associated with increased risks of suicidal behavior, substance misuse, injuries, and criminality. As we often discuss in our blogs, treatments for ADHD include medication and non-medication options, such as CBT (Cognitive Behavioral Therapy). While non-drug approaches are often used for young children or mild cases of ADHD, medications – both stimulants and non-stimulants – are common for adolescents and adults.
Global prescriptions for ADHD drugs have risen significantly in recent years, raising questions about their safety and effectiveness. Randomized controlled trials have demonstrated that medication can help reduce the core symptoms of ADHD. However, research from these trials still offers limited or inconclusive insights into wider and more significant clinical outcomes, such as suicidal behavior and substance use disorder.
An international study team conducted a nationwide population study using the Swedish national registers. Sweden has a single-payer national health insurance system, which covers nearly every resident, enabling such studies. The researchers examined all Swedish residents aged 6 to 64 who received their first ADHD diagnosis between 2007 and 2018. Analyses of criminal behavior and transport accidents focused on a subgroup aged 15 to 64, since individuals in Sweden must be at least 15 years old to be legally accountable for crimes or to drive.
The team controlled for confounding factors, including demographics (age at ADHD diagnosis, calendar year, sex, country of birth, highest education (using parental education for those under 25), psychiatric and physical diagnoses, dispensations of psychotropic drugs, and health care use (outpatient visits and hospital admissions for both psychiatric and non-psychiatric reasons).
Time-varying covariates from the previous month covered diagnoses, medication dispensations, and healthcare use. During the study, ADHD treatments licensed in Sweden included amphetamine, atomoxetine, dexamphetamine, guanfacine, lisdexamphetamine, and methylphenidate.
After accounting for covariates, individuals diagnosed with ADHD who received medication treatment showed better outcomes than those who did not. Specifically:
-Suicidal behaviors dropped by roughly 15% in both first-time and recurrent cases.
-Initial criminal activity decreased by 13%, with repeated offences falling by 25%.
-Substance abuse initiation declined by 15%, while recurring substance abuse was reduced
by 25%.
-First automotive crashes were down 12%, and subsequent crashes fell by 16%.
There was no notable reduction in first-time accidental injuries, and only a marginally significant 4% decrease in repeated injuries.
The team concluded, “Drug treatment for ADHD was associated with beneficial effects in reducing the risks of suicidal behaviours, substance misuse, transport accidents, and criminality, but not accidental injuries when considering first event rate. The risk reductions were more pronounced for recurrent events, with reduced rates for all five outcomes.”
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Background:
Pharmacotherapies, such as methylphenidate, are highly effective for short-term ADHD management, but issues remain with medication tolerability and adherence. Some patients experience unwanted side effects from stimulant medications, leaving them searching for alternative ADHD treatments. Alternative treatments such as cognitive training, behavioral therapies, psychological interventions, neurofeedback, and dietary changes have, so far, shown limited success. Thus, there is a critical need for non-pharmacological options that boost neurocognitive performance and address core ADHD symptoms.
First— What Are NIBS (Non-Invasive Brain Stimulation) Techniques?
Non-invasive brain stimulation (NIBS) techniques, including transcranial direct current stimulation (tDCS), transcranial random noise stimulation (tRNS), transcranial alternating current stimulation (tACS), and repetitive transcranial magnetic stimulation (rTMS) are generating growing attention within the scientific community.
NIBS techniques are methods that use external stimulation, such as magnets or electrical currents, to affect brain activity without any invasive procedures. In transcranial alternating current stimulation (tACS), for example, small electrodes are placed on the scalp of the patient, and a weak electrical current is administered.
The theory behind these techniques is that when a direct current is applied between two or more electrodes placed on specific areas of the head, it makes certain neurons more or less likely to fire. This technique has been successfully used to treat conditions like depression and anxiety, and to aid recovery from stroke or brain injury.
The Study:
Previous meta-analyses have produced conflicting indications of efficacy. A Chinese research team consisting of sports and rehabilitative medicine professionals has just published a network meta-analysis to explore this further, through direct comparison of five critical outcome domains: inhibitory control, working memory, cognitive flexibility, inattention, hyperactivity and impulsivity.
To be included, randomized controlled trials needed to have participants diagnosed with ADHD, use sham control groups, and assess ADHD symptoms and executive functions – such as inhibitory control, working memory, cognitive flexibility, inattention, hyperactivity, and impulsivity – using standardized tests.
A total of thirty-seven studies encompassing 1,615 participants satisfied the inclusion criteria. It is worth noting, however, that the authors did not specify the number of randomized controlled trials nor the number of participants included in each arm of the network meta-analysis.
Furthermore, the team stated, “We checked for potential small study effects and publication bias by conducting comparison-adjusted funnel plots,” but did not share their findings. They also did not provide information on outcome variation (heterogeneity) among the RCTs.
Results:
Ultimately, none of the interventions produced significant improvements in ADHD symptoms, whether in inattention symptoms or hyperactivity/impulsivity symptoms. Likewise, none of the interventions produced significant improvements in inhibitory control. Some tDCS interventions enhanced working memory and cognitive flexibility, but details about trial numbers and participants were missing. The team concluded, “none of the NIBS interventions significantly improved inhibitory control compared to sham controls. … In terms of working memory, anodal tDCS over the left DLPFC plus cathodal tDCS over the right DLPFC … and anodal tDCS over the right inferior frontal cortex (rIFC) plus cathodal tDCS over the right supraorbital area ... were associated with significant improvements compared to sham stimulation. For cognitive flexibility, only anodal tDCS over the left DLPFC plus cathodal tDCS over the right supraorbital area demonstrated a statistically significant benefit relative to sham. ... Compared to the sham controls, none of the NIBS interventions significantly improved inattention. ... Compared to the sham controls, none of the NIBS interventions significantly improved hyperactivity and impulsivity.”
How Should We Interpret These Results?
In a word, skeptically.
If one were to read just the study’s abstract, which states, “The dual-tDCS and a-tDCS may be considered among the preferred NIBS interventions for improving cognitive function in ADHD”, it might seem that the takeaway from this study is that this combination of brain stimulation techniques might be a viable treatment option for those with ADHD. Upon closer inspection, however, the results do not suggest that any of these methods significantly improve ADHD symptoms. Additionally, this study suffers from quite a few methodological flaws, so any results should be viewed critically.
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