Adjective
impressionable - Easily influenced by somebody or something, usually due to being inexperienced or naïve.

Because children tend to be very impressionable, their use of the internet should be monitored, so that they are kept away form undesirble influences.
frazzled - To feel completely exhausted and worn out, and unable to think straight, after a great deal of mental or physical effort
After being up two nights in a row writing a 60 page history paper, and drinking 60 cups of coffee, Simon's mind felt frazzled.