Adult ADHD disturbs subjective parameters of sleep, but its effects on objective patterns are less clear, according to a recent meta-analysis published in Neuroscience and Biobehavioral Reviews.
“While some studies reported an association between ADHD and sleep onset latency, poor sleep efficiency, high nocturnal motor activity, and restless legs syndrome in adults, others failed to find significant difference in important objective sleep parameters such as sleep latency, number of sleep awakenings, and total time in bed,” wrote the authors, led by Amparo Díaz-Romána, PhD; Mind, Brain and Behavior Research Center; University of Granada; Granada; Spain.
Emerging research suggests that children with ADHD present with significantly increased subjective complaints, as well as some objective changes exhibited on actigraphy and polysomnography. Moreover, these changes are not due to psychiatric comorbidity or ADHD drugs. Nevertheless, in light of developmental changes, findings in children may not necessarily translate to adults.
The authors note that the assessment and treatment of sleep issues in people with ADHD may help counteract impairment secondary to ADHD and help alleviate ADHD symptoms. However, to figure out how to help these people sleep better, experts must identify the mechanisms underlying these sleep issues. Thus, the authors performed a novel systematic review and meta-analysis of subjective and objective sleep changes in adults with ADHD.
In this study, the authors looked at a pool of 8,812 references, and retained a total of 13 studies for review. They employed random-effects models for each sleep variable to calculate standard mean differences (SMDs) with 95% CIs—correcting for bias secondary to sample size. They analyzed study quality using a state-of-practice tool called the Newcastle-Ottawa scale.
When compared with adults without ADHD, adults with ADHD demonstrated the following significant findings on analysis:
- Longer sleep onset latency (SMD: 0.67; 95% CI: 0.41, 0.92; P < 0.01)
- Increased psychosomatic symptoms during sleep onset (SMD: 0.64; 95% CI: 0.21, 1.07; P=0.04)
- More night awakenings (SMD: 0.56; 95% CI: 0.40, 0.73; P < 0.01)
- More general sleep problems (SMD: 1.55; 95% CI: 0.72, 2.39; P=0.003)
- Decreased sleep quality (SMD: 0.69; 95% CI: 0.38, 0.99; P < 0.01)
- Decreased sleep efficiency (SMD: –0.55; 95% CI: –0.83, –0.27; P=0.01)
- Increased daytime sleepiness (SMD: 0.75, 95% CI: 0.29, 1.21; P=0.01)
Adults with ADHD exhibited similar sleep duration and reported restorative value of sleep as compared with these parameters in adults without ADHD.
With respect to objective measures, according to actigraphic measures, adults with ADHD demonstrated significantly increased sleep onset latency (SMD: 0.80; 95% CI: 0.46, 1.14; P < 0.001) and significantly decreased sleep efficiency (SMD –0.68, 95% CI: –1.03, –0.34, P=0.001). Of note, the researchers observed no significant differences in polysomnographic parameters.
“It is not surprising that findings from this meta-analysis were different for subjective vs objective parameters, as these relate to different measures/constructs,” the researchers reflected. “Overall, our findings might be interpreted according to the ‘sleep-state misperception’ phenomenon, described in patients with primary or psychophysiological insomnia, who, despite subjective complaints of sleep problems, do not present with any significant alteration in polysomnographic parameters.”
One important limitation of this study is that the researchers did not adjust for psychiatric comorbidities and medication status, which may have played a role in the high heterogeneity of results observed in the study.
“Whereas subjectively reported sleep problems are significantly associated with ADHD in adults and should be systematically screened during the clinical interview,” concluded the researchers, “additional research is needed to understand if they are underpinned by objective sleep alterations.”
To read more about this study, click here.