A recent study found patients with fibromyalgia syndrome (FMS) have a higher rate of co-occurring adult attention-deficit/hyperactivity disorder (ADHD).
FMS is a chronic pain disorder that impacts a patient’s functioning. Symptoms may include musculoskeletal pain, chronic fatigue, sleep disturbance, and cognitive impairment. Cognitive impairment, or dyscognition, may include symptoms such as difficulty with concentration and attention, forgetfulness, and problems with word-finding and word fluency. These issues, sometimes called “fibro-fog,” may be more disabling than the chronic pain, but they are mostly under-recognized, the study authors wrote.
Patients with FMS have altered neurotransmitter activity involved in pain sensitivity, such as dopamine, serotonin, and noradrenaline. Likewise, ADHD is a chronic neurodevelopmental disorder also associated with impaired cognition and altered neurotransmitters.
In this cross-sectional observational study, 123 patients with FMS from a chronic pain clinic in South Africa were screened for adult ADHD using the World Health Organization Adult ADHD Self Report scale v1.1. The Revised Fibromyalgia Impact Questionnaire (FIQ-R) was used to assess the impact of FMS. Cognitive assessment was based on self-report in accordance with the 2011 modified American College of Rheumatology criteria and the FIQ-R, respectively.
Of the 123 participants, 44.72% (n = 55) screened positive for adult ADHD. Participants with both FMS and a positive adult ADHD screening test scored higher on the FIQ-R score (64.74, SD = 17.66, vs 54.10, SD = 17.10). Self-reported cognitive impairment was rated higher in the combined group (odds ratio [OR] = 10.61, 95% CI; 3.77–29.86, P
These results, published in Pain Medicine
, suggest that the co-occurrence of adult ADHD in FMS may be highly prevalent and may also worsen FMS. Patients with FMS should be assessed for the presence of adult ADHD.
“There are many aspects of fibromyalgia syndrome (FMS) that we do not yet fully understand, such as the exact pathophysiology, and the association with numerous other conditions,” Dr Roland van Rensburg, the lead author of the study, told The American Journal of Managed Care®
). “Most of these comorbidities have been well described, but in our practice we have noticed several patients with inattention and impaired cognition out of keeping with what is seen in most FMS patients. We then proceeded with a study to ascertain whether the cognitive impairment could be due to FMS with associated ADHD, based on underlying shared neurotransmitter dysfunctions.”
In an e-mail exchange with AJMC®
, he said that the key shared symptom of FMS and adult ADHD, impaired cognition, is the dominant feature in adult ADHD—more than the hyperactivity that is more frequently seen in childhood ADHD. Both of these conditions have underlying neurotransmitter dysfunctions, primarily dopamine and serotonin. FMS appears to be driven by polygene polymorphisms involving catechol-O-methyltransferase, serotonin transporters, and D4 dopamine receptor genes (DRD4), while adult ADHD involves polymorphisms in the DRD4 genes as well as dopamine transporter genes.
The main limitation of this study was that a self-screening questionnaire was used to identify adult ADHD. Although the WHO ASRS self-report questionnaire has been validated and shown to have excellent total classification accuracy of 97.9%, van Rensburg said, future studies should include a comprehensive clinical assessment to confirm ADHD. Another limitation is that none of the FMS participants in this study were treatment naÏve.
The diagnosis and management of FMS is shifting from the specialist to the general practitioner, van Rensburg said, citing 2012 Canadian Guidelines for the diagnosis and management of fibromyalgia syndrome
. He said the key takeaway for healthcare providers is for general practitioners “be equipped with simple, fast, and accurate screening tools to identify FMS, and to treat or refer patients as appropriate. Clinicians, especially those in primary healthcare, should screen all FMS patients for the presence of associated ADHD, and have a high index of suspicion for FMS in ADHD patients who have chronic pain or unexplained fatigues”
He plans future studies to see how ADHD stimulant medications affect not only cognitive impairment in FMS, but also chronic pain. An observational case study by Young et al suggested this when they found that ADHD patients with unexplained fatigue, widespread musculoskeletal pain, or a preexisting diagnosis of chronic fatigue syndrome or FMS, not only had improved symptoms of ADHD on stimulant medication, but also improvement of pain and fatigue, van Rensburg wrote.
Van Rensburg, R, Pieter Meyer, H, Hitchcock, SA, et al; Screening for Adult ADHD in Patients with Fibromyalgia Syndrome. Pain Med
. 2017; 0:1-7. Published November 1, 2017. Accessed December 28, 2017. doi.org/10.1093/pm/pnx275