B.A Psychology

Yes, you can do Bachelors in Psychology with Commerce.
DU guidelines:
1. You can apply in DU if you opted for psychology in class 11th and 12th, you have to include it in BFS (best four subjects), else, you will face a deduction of some percentage.
2. You can apply even if you haven't studied psychology in high school but then you will face deduction in BFS.
Other institutes:
Universities like Christ Bangalore, Jamia Milia Islamia conduct entrance test and you can appear with commerce stream even without having studied psychology in high school. General Psychology is where you learn about the facets of the mind, various theories which have shaped the course of psychology, personality, memory, learning and so on. It teaches the problem and the solution only. Applied Psychology is a specialised stream of the field where one learns to put the theories and principles of psychology to practical and tangible use in the everyday world. It specialises you in any of the fields: Child Counselling, Industrial, Sports Psychology, etc. It teaches not only the problem-solution but also how to apply the solutions in real life.