I've used a few types of Nootropics (brain pills) and I think it depends on the quality of the Nootropic in question. I think the benefit also depends on other factors such as your nutritional intake and what you do throughout the day.

I've used this one and noticed a solid improvement towards my mental clarity, ability to retain information, and focus: Bulletproof CILTEP Nootropic Stack

The bulletproof site that that product is sold on also has some amazing knowledge for those seeking to improve their mind and body by natural means and I find the information especially valuable to those with mental illnesses who have had negative experiences with the psychiatric system and prescription medication.

Keep in mind that they are a bit pricey, however. I think they're amazing though and I wish I could afford more right now.