NEET is the entrance examination for admission to MBBS,BDS, Ayush and Veterinary courses across India. But if you want to study Psychology in your Graduation, you needn't have to appear for NEET. You can take up Humanities or Science subjects in your 12th and then take up B.Sc Psychology. There is BA Psychology and then there is B.Sc Pscyhology. BA Psychology deals with Social aspect of Human Mind and Behaviour whereas B.Sc Psychology deals the Science and Mathematical aspect of Human Mind and Behaviour. So depending on your interest, you have to choose between BA Psychology or B.Sc Psychology. But just to answer your question, NEET is not necessary if you want to study Psychology. If you take up Psychology in your Bachelor's degree, you can become a Psychologist. But if you want to become a Psychiatrist, for that you need to study MBBS and then take up Psychiatry. For that you will need to appear for NEET. And to be eligible for NEET, you should have completed your 12th, passed in all subjects and secure a minimum aggregate of 50% in Physics, Chemistry and Biology. It is 50% for General Category, 45% for PWD and 40% for OBC,SC,ST.