A therapeutic target is the specific structure in the body, such as a receptor, enzyme or transporter, that a medicine is designed to act on to produce its effect.
For stimulant ADHD medication, the main targets are the transporters that move dopamine and noradrenaline back into nerve cells. Atomoxetine targets the noradrenaline transporter. Guanfacine targets a noradrenaline receptor.
Knowing the target explains why medicines differ. Two medicines with different targets can help the same person in different ways, or one can suit someone the other didn't. That is one reason a second medicine is sometimes tried when the first does not suit.
In research, the term also describes something a treatment aims to change, such as a specific skill or difficulty. A coaching programme might target starting tasks rather than ADHD as a whole.