The main trouble with becoming addicted to over the counter stimulants is that you're going to become immune to the effect they have on you and you're going to have to ingest more of them to achieve your desired effect.

This is not healthy and could interfere with other medications you're taking.

They can be expensive.

Addiction to over the counter stimulants can cause sleep deprivation. This is extremely harmful to yourself and others. You need sleep to refresh and revitalize your system. Without sleep you are overtaxing yourself and this can lead to serious health trouble.

Stimulants cause your heart to beat faster and dilates your blood vessels. Over an extended period of time this can cause your heart to give out and perhaps rupture a blood vessel .

Instead of the stimulant keeping your aware of what is going on, it is going to have the opposite effect. You're going to be pumped and jittery, but you're not going to be as alert as you would prefer. It is not safe to operate heavy machinery under these conditions.

When you crash, or come down from the effects of stimulant abuse , you're going to have withdrawal symptoms and most likely, you're going to crave more of the stimulant. You may have to seek medical attention to return to your old self.

Taking over the counter stimulants along with consuming other large amounts of caffeine can really cause trouble. This can lead to heart attack , strokes and can permanently damage your circulatory system.