Astudent has difficulty sleeping regularly, has problems with paying attention in class and with learning and suffers from depression. this student may not have enough of the neurotransmitter (best answer):

I believe the answer is: Serotonin

The serotonin in our body would regulate the mood and desire that we felt on day to day basis, which might also influence our social behaviour. People who had low serotonin tend to had strong desire to achieve things in live, which may lead to lack of concentration in their job and higher chance of depression.

answer; deontological theory;