22. Chronic pain / muscle tension in ADHD

Author: Ulrich Brennecke
Review (March 2024): Dipl.-Psych. Waldemar Zdero
Completely revised: December 2024

• 1. Chronic pain and ADHD
• 2. Axial pain and ADHD
• 3. Increased muscle tension in ADHD
• 4. Causal pathways for chronic pain, increased muscle tone and fibromyalgia

1. Chronic pain and ADHD¶

People with ADHD often show increased sensitivity to pain. High ADHD scores correlated with increased pain¹
Chronic pain and pain intensity in patients with ADHD are associated with muscular dysregulation.²

In children with chronic pain (without headaches) an ADHD prevalence of 15 to 25 %, i.e. 2 to 5 times higher (meta-analysis).³
72.5% of adults referred to a pain clinic for chronic pain and a probable somatic syndrome disorder met the diagnostic criteria for ADHD.⁴ Of 60 adults with chronic non-specific lower back pain, 31.5% had ADHD.⁵
Psychiatric patients with chronic pain show a higher prevalence of ADHD than psychiatric patients without chronic pain.²
Children with ADHD showed a prevalence of chronic pain of up to 66% (at least weekly pain for more than 3 months). Stimulant treatment reduced the rate of chronic pain. Another study found a reduced perception of pain in adolescents with ADHD, which disappeared with stimulant treatment.³
Of young women with ADHD and/or ASD, 76.6%⁶ and 75.9% reported chronic pain, respectively, compared to 45.7% of unaffected young women⁷.
80% of the people with ADHD studied reported chronic pain at .⁸

One study found ADHD in 25 of 30 patients with refractory orofacial pain (83.3%; women: 20).⁹
ADHD was associated with a 32% increased risk of migraine, while the risk of tension headaches was unchanged.¹⁰¹¹ Children with migraine had a 2.6-fold risk of ADHD, while the prevalence of migraine in children in general was 3.76%. Migraines correlated particularly with hyperactivity and impulsivity, not inattention.¹² Children with ADHD have a 2.6-fold risk of migraine in ADHD, whereas the prevalence of migraine in children in general was 9.9% in this study¹¹

2. Axial pain and ADHD¶

Chronic pain in patients with ADHD is characterized by widespread and axial pain that starts early. This “ADHD pain” is qualitatively different from chronic pain in patients without ADHD.²
Axial pain occurred in 86.6% of persons with ADHD, in 50% of those not diagnosed with ADHD, and in 21.4% of those who also did not have subclinical ADHD.
People with subclinical ADHD showed the same muscular dysregulation as people with ADHD.²
While ADHD is a predictor of “axial pain”, affective disorders, anxiety disorders or personality disorders were not.²

The axial muscles are:

• Head and neck muscles
• Spinal muscles
• Other trunk muscles
• Pelvic floor muscles

Axial muscles regulate and control posture and are constantly used to maintain the naturally unstable upright position. Muscular dysregulation has a significant impact here and could lead to high muscle tone with consequent widespread pain and lower back pain¹³

• Erector spinae
• Latissimus dorsi
• Iliopsoas
  • connects the lumbar spine with the lower limbs
  • Iliopsoas spasms can increase lumbar lordosis and lumbar pain¹⁴

Gene variants that correlate with neck or shoulder pain causally increase the risk of ADHD.¹⁵

3. Increased muscle tension in ADHD¶

ADHD is often associated with increased muscle tension. This is not an expression of hyperactivity or a fundamental motor dysfunction. There are high-performance athletes with ADHD; they are unlikely to have severe motor dysfunction. Nevertheless, increased muscle tension can also be observed in them.

Muscle tension, especially in the shoulder/neck area, occurs much more frequently with ADHD.
So far, we have been unable to find a plausible neurophysiological explanation for this.
An orthopaedist explained to us that during sleep, the muscles further away from the trunk (spine) relax first, while those on the spine relax last. These need undisturbed deep sleep in order to relax. Accordingly, muscle tension could also be a consequence of impaired sleep in ADHD.

With regard to fibromyalgia, which is often associated with greatly increased muscle tension, helpful treatment with very low-dose naltrexone is reported (0.5 to 4.5 mg instead of the usual 150 mg). The treatment is said to be virtually free of side effects.^1617181920 Naltrexone is a long-acting competitive opioid antagonist that is also used to treat alcohol and opioid dependence. One person with ADHD told us that the low-dose naltrexone also helped with the ADHD symptoms.
Paracetamol was repeatedly mentioned as a treatment option.
Magnesium is also helpful.
Myotonolytics (e.g. methocarbamol, tolperisone, tetrazepam, flupirtine, tizanidine, baclofen, pridinol, eperisone or methocarbamol) have a muscle-relaxing effect by inhibiting polysynaptic reflex conduction in the spinal cord and in subcortical centers. However, they are less suitable for long-term use and have significant side effects. Tizanidine and cyclobenzaprine have a sedative effect and can help with existing sleep problems.²¹ Methocarbamol and metaxalone are slightly less sedating, but probably also less effective. Dizziness and drowsiness are reported with all myotonolytics.

4. Causal pathways for chronic pain, increased muscle tone and fibromyalgia¶

According to Stray, motor disinhibition and increased muscle tone in ADHD are directly associated with dysregulation of the dopamine and noradrenaline systems.²²
It is fitting that the increased muscle tone in ADHD is reduced by methylphenidate²³ and that a noradrenaline reuptake inhibitor (orphenadrine, Norflex®) serves as a skeletal muscle relaxant. Noradrenaline reuptake inhibitors are also used as ADHD medication (atomoxetine, viloxazine).

One study reports an increased sphingomyelin/ceramide ratio in patients with lower back pain²⁴ (which is also a typical form of ADHD). The acid sphingomyelinase (ASM, sphingomyelin phosphodiesterase 1, encoded by the ADHD candidate gene SMPD1) Degrades sphingomyelin to ceramide. If sphingomyelin is high and ceramide is low, this indicates weak S-ASM. With this in mind, FIASMA (ASM inhibitors) could be detrimental and increase the risk of muscle tension. Whether this idea is supportive for ADHD remains to be seen

See also Chronic pain and muscle tension in ADHD - neurophysiological correlates