Is it wise for a BPAD (bi-polar affective disorder) recovered student to enrol for PhD?
I'll start with the basics: doing a PhD usually implies a lot of stress, and the process is both very competitive and tense. However, it depends a lot on the environment around the student. Therefore, without knowing your specific medical situation (and not being a medical expert, even if I knew all about you), you may not get a more useful answer than: yes, it is possible, but you have to be very careful about ensuring that this is done in an environment compatible with your condition, and be prepared to quit if you have to choose between your health and your job (recognize early on that failure is always an option). It will be hard, but I don't think it's impossible.

If you are to enroll in a PhD (or graduate program, I don't know the details of India’s graduate-level education system), it has to meet certain conditions:


Make sure that the people taking you on as advisor and department head know of your condition, and wholeheartedly embrace the idea of you having special needs
Discuss it with the doctor that follows you regularly. Also bring into the discussion your future institution's resident doctor, because he is (in most countries, by law) the person who will mediate between you and your institution if problems arise.
Realize that if you love research, it's not only a PhD, but already think of your career ahead.


A last note of hope: in many countries, people with disabilities are allowed by law to obtain work adjustments from their employers. This is more commonly done for people with physical disabilities, but I know at least one person who successfully obtained very specific (and very large) adjustments to his PhD program because of his mental health (this is in France, if it makes any difference).