22. 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 any fundamental motor dysfunction. Nevertheless, increased muscle tension can also be observed in them.

According to Stray, motor disinhibition and increased muscle tone in ADHD are directly associated with dysregulation of the dopamine and noradrenaline systems.¹
It is fitting that the increased muscle tone in ADHD is reduced by methylphenidate² 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).

The reticular system is involved in³

• Regulation of the arousals
• Maintaining muscle tone.

The reticular formation can ³

• activate several muscles at the same time
• Modulate body position adjustments for balance
• this can affect the stabilizing muscles (the proximal limb muscles and muscles that stabilize the spine).

The reticulospinal system (the entirety of the descending fibers from the reticular formation) is important for³

• Regulation of posture control
• Regulation of movements
• Reduction in muscle activity during REM sleep

Muscle tension, particularly 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. This means that muscle tension could also be a consequence of impaired sleep in ADHD.