Exploring the latest clinical research on Attention-deficit hyperactivity disorder (ADHD) with Dr. Ray O’Connor
Attention-deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental condition. In the US, ADHD affects an estimated 9.8% of children and adolescents, and 4.4% of adults. This disorder is linked to various psychiatric and physical issues, as well as negative functional outcomes. Notably, individuals with ADHD face a doubled risk of premature death, primarily due to non-natural causes.
Dr Ray O’Connor
For individuals diagnosed with ADHD, pharmacological treatment involving stimulant and nonstimulant medications, in conjunction with nonpharmacological approaches, is recommended. A recent cohort study in Sweden1 aimed to assess if starting ADHD pharmacotherapy could lower the overall mortality risk in individuals with ADHD.
The study identified individuals aged six to 64 years with a new ADHD diagnosis between 2007 and 2018, who had not received ADHD medication before. Follow-up commenced from the ADHD diagnosis date until death, emigration, two years post-diagnosis, or December 31, 2020. The findings indicated that 148,578 individuals with ADHD (41.3% females and 56.7% males) began ADHD medication, with a median age of 17.4 years at diagnosis.
Those following the treatment initiation strategy had a lower two-year mortality risk (39.1 per 10,000 individuals) compared to those not following it (48.1 per 10,000 individuals), especially for non-natural causes of death.
What is the actual global prevalence of ADHD? Estimates vary significantly across studies. Previous reviews attribute this variability to methodological differences, such as diagnostic criteria, data sources, and impairment criteria for diagnosis.
In a systematic review and meta-analysis2, researchers analyzed studies reporting ADHD prevalence in representative samples of European and global children and adults. Out of 117 studies evaluated, the overall ADHD prevalence varied depending on study type.
Prevalence rates were 1.6% in register studies, 5.0% in survey studies, 4.2% in one-stage clinical studies, and 4.8% in two-stage clinical studies. The authors concluded that comparing prevalence data from studies with different methodologies necessitates consideration of these factors.
What contributes to the development of ADHD? Could family dynamics play a role? Parenting practices and family environment significantly impact child development, including executive function, attention, self-regulation, and the risk of developmental disorders like ADHD.
In a systematic review and meta-analysis3 on parenting and family environment as risk factors for ADHD in children, factors like parenting quality, maltreatment, parental relationship status, parental incarceration, and child media exposure were analyzed. All factors, except sensitivity/warmth, showed a direct association with ADHD outcomes. The findings suggest that parenting and family environment can influence ADHD symptoms and the likelihood of an ADHD diagnosis. The authors recommend interventions supporting parents to enhance children’s long-term development.
Concerns exist regarding the safety of current ADHD medications, particularly their cardiovascular effects and abuse potential. Therefore, there is a demand for safer and more effective ADHD treatments for adults. A review article4 identified 90 eligible randomized controlled trials (RCTs) from the clinical trials register.
Among these trials, 24 reported statistically significant results for primary efficacy endpoints. While various interventions showed superiority over the control condition in a single RCT, centanafadine (a norepinephrine, dopamine, and serotonin reuptake inhibitor) was the sole treatment demonstrating efficacy on core ADHD symptoms across multiple RCTs, with reasonable tolerability. The authors concluded that the existing RCTs for adults with ADHD are insufficient and advocate for the development and testing of additional effective and well-tolerated treatments.
Is a blood test on the horizon for diagnosing ADHD? Metabolomics offers a promising avenue by identifying biomarkers for precise diagnosis and targeted interventions. A systematic review5 examining metabolomic insights into ADHD found no simple blood test currently available for clinical use.
The review highlighted intricate connections between ADHD and altered amino acid metabolism, neurotransmitter imbalances (especially dopamine and serotonin), oxidative stress, and the kynurenine pathway affecting neurotransmitter balance. Distinct metabolic patterns, particularly in the kynurenine pathway, hold potential as future diagnostic markers.
References:
- Li L et al. ADHD Pharmacotherapy and Mortality in Individuals With ADHD. JAMA 2024 Mar 12;331(10):850–860. doi: 10.1001/jama.2024.0851
- Popit S et al. Prevalence of attention-deficit hyperactivity disorder (ADHD): systematic review and meta-analysis. European Psychiatry 2024, 67(1), e68, 1–23 https://doi.org/10.1192/j.eurpsy.2024.1786
- Claussen A et al. All in the Family? A Systematic Review and Meta‑analysis of Parenting and Family Environment as Risk Factors for Attention‑Deficit/Hyperactivity Disorder (ADHD) in Children. Prevention Science 2022 https://doi.org/10.1007/s11121-022-01358-4
- Veronesi G et al. Treatments in the pipeline for attention-deficit/hyperactivity disorder (ADHD) in adults. Neurosci Biobehav Rev 2024 Aug:163:105774. doi: 10.1016/j.neubiorev.2024.105774 Epub 2024 Jun 22.
- Predescu E et al. Metabolomic Markers in Attention-Deficit/Hyperactivity Disorder (ADHD) among Children and Adolescents—A Systematic Review. Int. J. Mol. Sci. 2024, 25, 4385. https://doi.org/10.3390/ijms25084385