From the Guidelines
In ADHD, dopamine and norepinephrine levels are generally decreased in specific brain regions, which is supported by the mechanism of action of medications used to treat the condition, such as methylphenidate and amphetamine, that work by increasing the availability of these neurotransmitters in the brain 1. The primary medications used to treat ADHD, such as methylphenidate (Ritalin, Concerta) and amphetamine-based medications (Adderall, Vyvanse), work by increasing the availability of dopamine and norepinephrine in the brain.
- Methylphenidate primarily blocks the reuptake of dopamine and norepinephrine,
- while amphetamines both block reuptake and increase their release. Non-stimulant medications like atomoxetine (Strattera) specifically target norepinephrine reuptake, and by doing so, also increase dopamine levels in the prefrontal cortex, as dopamine transporters are scarce in this region 1. The effectiveness of these medications in reducing ADHD symptoms supports the theory that the condition involves insufficient dopamine and norepinephrine signaling, particularly in the prefrontal cortex and associated neural circuits that regulate attention and behavior. Key points to consider when treating ADHD include:
- The use of stimulant medications, such as methylphenidate and amphetamine, as first-line treatments
- The potential for non-stimulant medications, such as atomoxetine, to be effective in treating ADHD, particularly in patients who cannot tolerate stimulant medications
- The importance of monitoring patients for potential side effects, such as changes in appetite, sleep disturbances, and increased blood pressure and heart rate. Overall, the current evidence suggests that dopamine and norepinephrine levels are decreased in ADHD, and that medications that increase the availability of these neurotransmitters can be effective in reducing symptoms of the condition 1.
From the Research
Dopamine and Norepinephrine Levels in ADHD
- Dopamine and norepinephrine levels are modulated by medications used to treat ADHD, such as methylphenidate and amphetamines 2, 3, 4, 5, 6.
- These medications increase synaptic dopamine levels, with amphetamines being the most robust agents in doing so 2, 3, 4.
- Methylphenidate and amphetamines also block the reuptake of norepinephrine, increasing its levels in the brain 2, 3, 4, 6.
- The increase in dopamine and norepinephrine levels is thought to contribute to the therapeutic effects of these medications in treating ADHD symptoms 2, 3, 4, 5, 6.
Baseline Dopamine and Norepinephrine Levels in ADHD
- The studies provided do not directly address whether dopamine and norepinephrine levels are decreased or increased in individuals with ADHD compared to those without the disorder.
- However, the fact that medications that increase dopamine and norepinephrine levels are effective in treating ADHD symptoms suggests that these neurotransmitters may play a role in the pathophysiology of the disorder 2, 3, 4, 5, 6.