Which of the following is a key effect of amphetamines?

The key effect of amphetamines, particularly in the context of their medical use, is improved symptoms of ADHD. Amphetamines work by increasing the levels of certain neurotransmitters in the brain, such as dopamine and norepinephrine. This action helps to enhance focus, attention, and impulse control, which are often challenging for individuals with Attention Deficit Hyperactivity Disorder (ADHD).

While amphetamines can indeed lead to various side effects such as increased energy levels and potential for misuse, their primary therapeutic role is to provide a beneficial effect in managing ADHD symptoms. This use is supported by numerous clinical studies demonstrating that amphetamines can significantly improve concentration and reduce hyperactive behavior in individuals diagnosed with ADHD.