Hello dear..For Psychologist MBBS degree is not necessary.

MBBS prepare you for Psychiatrist not Psychologist.

you can pursue B.A or B.Sc and later your masters in Organizational Behavior or Industrial and Organizational Psychology.

To pursue your profession as Psychologist you have to do bachelor's and master's  degree in psychology and other certified degree and diploma courses. Psychologist are also expected to do internships in related field. Psychologist ae trained to administer psychological tests.

Hope you got your answer.

Good luck

Dear Spurti,
For pursuing a career in industrial and organisational psychology, there is no need of  MBBS.
The minimum requirement for working as an I/O psychologist is a master's degree. To become an Organizational Psychologist, one must meet the criteria for a general psychologist's licence: 3 years studying bachelor's degree in Psychology, 4th year Honours degree or Postgraduate Diploma in Psychology, and two-year full-time supervised practice.
Since, there are very limited job opportunities for industrial or organizational psychologists holding only bachelors degrees, though, the majority of these professionals will also go on to earn advanced degrees. Those with masters degrees in this area will often be able to start their industrial and organizational psychology careers in entry level positions. Those with Ph.D.'s, however, will usually be considered for even more employment opportunities in this field, and they will have an edge over the competition. Hence, for better employment opportunities you may complete your PHD for the same too.
Cheers!
Hope it helps.