Adderall is a combination of amphetamine and dextroamphetamine, two central nervous stimulants that improve focus and reduce impulsivity by increasing dopamine and norepinephrine levels in the brain.
Since Adderall has ensured that dopamine remains present, the brain will make less of it. When Adderall then leaves the bloodstream and dopamine levels drop, the good feelings will also disappear.
Adderall has been used as an off-label treatment for depression in patients who experience depression in combination with ADHD. Because stimulants can increase alertness, attention, and energy, they can feel like mood boosters for those experiencing depression.