How does GABA affect ADHD?
GABA is an inhibitory or ‘calming’ neurotransmitter while glutamate is the excitatory or ‘stimulating’ neurotransmitter. Recent research has revealed that an imbalance of these two neurotransmitters may increase the risk of developing ADHD. GABAergic interneurons, which help regulate brain activity, are now understood to play a part in the underlying causes of ADHD. When these neurons don’t work as they should, the balance between brain stimulation and brain calm is disrupted, potentially leading to symptoms such as inattention, impulsivity, and hyperactivity.
GABAergic interneurons are special types of brain cells that help control the flow of signals in the brain. They release GABA to help slow brain activity and regulate the firing of other neurons. Think of GABAergic interneurons as traffic controllers for brain signals, helping to keep everything in balance.
When neurons in the brain become too active, GABAergic interneurons send out GABA to reduce this activity, which keeps excitability under control and prevents overstimulation. This balance is essential for attention, mood, and various cognitive functions. In conditions like ADHD, disruptions in these cells' functioning can lead to difficulties with focus, impulsivity, and other symptoms.
Neuroimaging studies reveal that basal GABA levels are reduced in specific brain regions of ADHD patients. 2
Children with ADHD are found to have significantly reduced GABA concentration as well as reduced short intercortical inhibition. Cerebral cortical inhibitory function depends on GABAergic transmission and is vital for filtering sensory information and selecting appropriate behavioral responses. 3
A 2002 study comparing levels of GABA between people with and without ADHD found that while resting levels are similar, tasks requiring attention control are not. People with ADHD show smaller increases in GABA compared to those without ADHD, as well as poorer task performance. This may indicate that impaired GABAergic responses in key brain areas may contribute to the attention control challenges seen in ADHD. 4
