By Gustavo Arellano
By R. Scott Moxley
By Alfonso Delgado
By Courtney Hamilton
By Joel Beers
By Peter Maguire
By Charles Lam
By Charles Lam
The brain of someone who does not have the disorder operates at a baseline of stimulation, so psychostimulants would put them in a state of overstimulation, resulting in the rush drug abusers seek. But when an ADHD patient is given a stimulant, he or she drops dramatically to a state of understimulation for a few minutes, then gradually reaches a baseline of normal stimulation that allows him or her to concentrate.
The area of the brain most responsible for stimulation from drugs is the nucleus accumbens in the midbrain; it’s one of the structures popularly referred to as the Pleasure Center. It is abundant in dopamine receptors, where the many micro-pleasure parties take place.
Most people think of dopamine as a chemical or transmitter responsible for stimulation or excitement. It’s actually an inhibitory transmitter that tries to stop any excitement from occurring. The nucleus accumbens is where excitement occurs when bursts of dopamine are sustained to inhibit cells that release another inhibitory transmitter called GABA. By inhibiting the inhibitor, dopamine excites the nucleus accumbens.
Nearly all abused drugs increase dopamine release in the nucleus accumbens, but psychostimulants directly stimulate this part of the Pleasure Center. Ritalin does so in a short, intense fashion, while Adderall increases and decreases its effects gradually and sustains them over a longer period of time.
In large doses, Adderall produces the same chemical effects in the brain as amphetamines, while producing an intense feeling that more of the drug is needed to sustain the high. This is due to another event that happens in the brain with amphetamines: the blocking of the natural process where dopamine recycles itself.
Normally, when dopamine is released by a neuron, it stimulates another neuron, giving the excitement effect. When it is finished, dopamine returns to the original neuron and is recycled so it may be released again. This is known as “reuptake.” Amphetamines and ADHD drugs block reuptake; after overstimulating the second neuron, dopamine is washed away, never to be used again.
This eventually results in a low amount of dopamine in each neuron, despite the drug communicating with the brain to release all it has. The user will take more of the drug in hopes of experiencing the dopamine excitement, but there isn’t enough dopamine to create the rush.