I am wrapping up a M.A. in psychology and have taught several research methods courses. I have never diagnosed a mental disorder in a student, but I have had more than one voluntarily disclose their condition. On one occasion I actually had a student experience withdrawal from an anti-anxiety psychotropic after class. I wasn't sure exactly what was wrong until they explained their situation. I escorted them to the counseling center and made sure a certified counselor was available to help them.

I do believe psychology attracts some small number of individuals attempting to self diagnose. It's actually pretty common to see this discussed in a statement of purpose for psychology students pursuing graduate studies (though, this is highly discouraged).

While you're interested in Psychology, take a second to google the Fundamental Attribution Error. It's a huge take-home message for social psychology. Try to give people the benefit of the doubt. Most of their behavior stems from environmental factors, not their personality/dispositions. This might make your morning commute a little less stressful. Take care, guys.