October 5, 2023

Can Computers Train the Brain to Cure ADHD?

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.

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Meta-analysis finds little to no association between prenatal cannabis exposure and offspring ADHD

Meta-analysis Finds Little-to-No Association Between Prenatal Cannabis Exposure and Offspring ADHD

Prevalence of cannabis use among pregnant women is on the rise with the spread of legalization. The most frequently reported reasons for use are to relieve stress or anxiety, nausea or vomiting, pain, and for recreation.

Given that the primary psychoactive ingredient of cannabis, ∆9-tetrahydrocannabinol (THC) is a small fat-soluble molecule that can easily cross the placenta, an Israeli-U.S. research team conducted a systematic search of the peer-reviewed medical literature for studies exploring possible neuropsychiatric effects on offspring.  

They included not only studies evaluating likelihood of ADHD, but also autism spectrum disorder, anxiety, depression, and psychotic symptoms. For each of these, adjustment was made for known confounding variables.

With that adjustment, meta-analysis of six studies with a total of over half a million (503,661) participants reported a 13% increase in the odds of ADHD in offspring of mothers using cannabis during pregnancy compared with offspring of mothers not using cannabis while pregnant.

That is generally considered a small effect size increase in risk. But there are multiple reasons to question even this minimal finding:

  • It barely achieved statistical significance.
  • A few studies used more reliable clinical diagnoses, while most just used ADHD symptom rating scales.
  • It is virtually impossible to eliminate all confounding variables. Twin studies come closest to fully accounting for otherwise unmeasured environmental and genetic confounders, but no such studies were included.
  • The team made no effort to evaluate publication bias.  
  • Almost all the participants (497,821) were in a single study, and that study – which relied on clinical diagnoses – did not find a significant association.

Meta-analysis of two studies with a total of 741 individuals reported a 20% increase in offspring use of cannabis among mothers who used cannabis during pregnancy, but once again this was subject to methodological shortcomings:

  • Two studies do not make for a robust meta-analysis, even more so with only 741 participants.
  • The result barely achieved statistical significance.
  • Publication bias was unaddressed.
  • Small effect sizes are questionable due to the virtual impossibility of eliminating all confounding variables, especially without twin studies.

Some studies have suggested a link between cannabis and psychotic symptoms. But meta-analysis of four studies combining over nineteen thousand persons found no significant association between maternal cannabis use during pregnancy and offspring psychotic symptoms.

Many studies have pointed to commonalities in the etiology of ADHD and autism spectrum disorder (ASD). Yet meta-analysis of five studies encompassing over half a million participants found absolutely no association between maternal prenatal cannabis use and ASD.  

The remaining meta-analyses also reported no association with depression or anxiety.

With the caution that absence of evidence is not the same as evidence of absence, it is by no means clear from what is presently known that prenatal cannabis exposure has any significant neuropsychiatric effects on offspring. And if further research finds any effects, they are likely to be minor.

July 26, 2024

Meta-analysis Associates Dasotraline with Some Reduction in ADHD Symptoms

Meta-analysis Associates Dasotraline with Some Reduction in ADHD Symptoms

Dasotraline is a serotonin-norepinephrine-dopamine reuptake inhibitor (SNDRI) that had been under development by Sunovion for treating ADHD and binge eating disorder.  

An Indian research team conducted a systematic search of the peer-reviewed medical literature to perform meta-analyses of the quantitative outcomes of clinical trials. 

Meta-analysis of five double-blinded randomized clinical trials (RCTs) with a combined total of 1,498 participants reported a small-to-medium effect size reduction in ADHD symptoms in patients given dasotraline as opposed to those given placebo. 

There were, however, strong indications of publication bias. Using the trim-and-fill procedure to correct for that bias yielded a small effect size reduction in ADHD symptoms in patients given dasotraline compared with those given placebo. 

Insomnia were more than four times more frequent among patients given dasotraline than among those given placebo. There was no evidence of the frequency of insomnia being dose-dependent. 

Similarly, patients given dasotraline were more than four times more likely to report decreased appetite than those receiving placebo. In this case, however, the effect was clearly dose-dependent, rising from 3x for 2mg to 4x for 4mg to 5x for 6mg and almost 8x for 8mg. 

The authors concluded, “dasotraline can reduce the core symptoms of ADHD, that is, hyperactivity/impulsivity and inattentiveness, leading to an overall improvement of ADHD compared to placebo. Dasotraline can also improve clinician-determined patients’ global functioning compared to the placebo. The most common adverse drug reactions related to dasotraline were insomnia and decreased appetite. However, to fill the knowledge gap, multicentric randomized active-controlled clinical trials are warranted in this domain for a successful translation into clinical practice.” 

Weighing these less than impressive initial results against the cost of further RCTs, Sunovion withdrew its application for approval by the Food and Drug Administration, stating, “while Sunovion considers dasotraline to be a promising, novel treatment for binge eating disorder and ADHD, we believe that further clinical studies would be needed to support a regulatory approval for dasotraline in these indications.” 

July 25, 2024

Meta-Analysis: Young People with ADHD Experience Serious Social Cognition Impairments

Meta-analysis Concludes Children and Adolescents with ADHD Experience Serious Impairments in Social Cognition, Affecting Social Functioning

Children and adolescents with ADHD are known to have difficulties in relating to family members, peers, and teachers. Over the long run this can contribute to anxiety or even delinquency. 

Several cognitive functions that allow individuals to process social information and interact with others contribute to shaping everyday social interactions. These include: 

  • Theory of mind (ToM): Being able to attribute mental states to others, and thus explain and predict their behaviors. 
  • Empathy: Being able to feel an appropriate emotion in response to another person’s mental state, and thereby understand others’ feelings. 
  • Emotion recognition: Being able to identify emotions in facial expressions and other communication cues, such as voice and body position. 

A European research team performed a systematic search of the peer-reviewed medical literature to conduct meta-analyses of ToM, Empathy, Facial and Non-Facial Emotion Recognition in children and adolescents with ADHD when compared to typical development. As a comparison measure, they also included Everyday Social Skills (using self, parent, teacher, or clinician questionnaires/interviews of social skills) as an outcome. 

The search yielded 142 case-control studies (including dissertations) with a total of 16,283 participants. 

Meta-analysis of 82 studies with a combined total of 10,770 participants found a very large effect size impairment in everyday social skills among children and adolescents with ADHD when compared with typically developing peers. Adjusting for covariates only strengthened the finding. There was no sign of publication bias. 

This was mirrored in three out of five measures of social cognition: 

  • Theory of mind (ToM): Meta-analysis of 49 studies with a total of 2,449 participants identified a large effect size impairment among children and adolescents with ADHD when compared with typically developing peers. Adjusting for covariates made no difference in the outcome. There was no sign of publication bias. 
  • Empathy: Meta-analysis of twelve studies combining 916 individuals yielded a medium effect size impairment among children and adolescents with ADHD. But there were strong signs of publication bias, and the outcome lost significance after adjusting for covariates (perhaps because it became under-powered with three studies pooling only 151 persons). 
  • Facial emotion recognition: Meta-analysis of 43 studies with a total of 3,369 participants reported a medium effect size impairment among children and adolescents with ADHD after adjusting for covariates. There was absolutely no indication of publication bias. 
  • Non-facial emotion recognition: Meta-analysis of eight studies encompassing 707 persons reported a small effect size impairment with signs of publication bias that became insignificant after adjusting for covariates. 

The team concluded, “Our findings show that children and adolescents with ADHD have deficits in ToM, Facial Emotion Recognition, and Everyday Social Skills, three domains that warrant clinical attention.” 

July 22, 2024