Side effects of stimulants include which of the following?

• A. Insomnia
• B. Sleep improvement
• C. Lower heart rate
• D. Weight gain

Answer: (A)

Stimulants boost brain and body arousal by increasing neurotransmitter activity, which makes you more awake and alert. This heightened arousal can interfere with the ability to fall asleep, especially if the stimulant is taken later in the day, so insomnia is a common side effect.

Sleep improvement isn’t typical because the same arousal that keeps you awake won’t help you sleep. A lower heart rate is unlikely since stimulants usually raise heart rate and blood pressure through sympathetic activation. Weight gain also doesn’t fit, as stimulants often suppress appetite and can lead to weight loss rather than gain.