Dopamine is the primary neurotransmitter involved in the regulation of attention, motivation, and reward, which are all impaired in ADHD.

Stimulants, such as methylphenidate and amphetamine, are the most commonly prescribed and effective medications for ADHD.

Stimulants increase the levels of dopamine and norepinephrine in the brain, which improves attention, focus, and behavior in individuals with ADHD.

Methylphenidate, dextroamphetamine, and lisdexamfetamine are all psychostimulants commonly used to treat ADHD in children and adolescents.

Insomnia is the most common side effect of psychostimulants in individuals with ADHD, particularly when taken in the late afternoon or evening.

Atomoxetine, clonidine, and guanfacine are all nonstimulant medications commonly used to treat ADHD in children and adults.

Atomoxetine inhibits the reuptake of norepinephrine in the brain, which improves attention, focus, and behavior in individuals with ADHD.

Increased appetite is not a common side effect of atomoxetine, unlike nausea, vomiting, and constipation.

Clonidine is commonly used to treat ADHD in children and adolescents with comorbid tics, as it can help to reduce the severity of tics.

Clonidine activates alpha-2 adrenergic receptors in the brain, which leads to decreased sympathetic nervous system activity and improved attention and behavior in individuals with ADHD.

Increased heart rate is not a common side effect of clonidine, unlike drowsiness, dry mouth, and constipation.

Lisdexamfetamine is a psychostimulant that is commonly used to treat ADHD in adults due to its long duration of action and reduced risk of abuse compared to other stimulants.

Guanfacine activates alpha-2 adrenergic receptors in the brain, which leads to decreased sympathetic nervous system activity and improved attention and behavior in individuals with ADHD.

Increased heart rate is not a common side effect of guanfacine, unlike drowsiness, dry mouth, and constipation.

Methylphenidate is the only medication approved by the FDA for the treatment of ADHD in preschool-aged children.