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).
The bad news
Your doctor has warned you not to be in tense situations.
Listen to your doctor.
Like somewhere around 10-25% of the population, you have challenges to your mental health. Those are challenges you have to live with and work with. For that, you will benefit from medical support.
So listen to your doctor.
Doing a PhD is a lot of stress. A lot of stress.
From what you've written, according to your doctor, you are not in a position to take on that stress. So don't.
The good news
There are lots of ways forward from here. There's lots of good evidence-based psychology going on, in India (for example at the CARE Institute of Behavioural Sciences, Chennai) and elsewhere, that may be able to help you develop your own early intervention toolkit to help prevent any recurrence of your former ill health. Such a toolkit might conceivably give you the tools you need to take on a PhD in the future, and to deal with the other challenges that life offers.
Final caveat
And life will throw enough stress-inducing events at you anyway: there's no need to go seeking out additional ones, until you've got the tools you need to handle them, so don't.
Just listen to your doctor.
I'd love to tell you to pursue your dream, but it's not as easy. As Daniel said, a PhD (almost?) always leads to some tense situations. However, I wouldn't be as pessimistic (or at least as definite) as he was.
First, Jack's comment is right on spot: we cannot give medical advices. IMO, you should discuss this with your doctor. How much stress can you take? For how long would it be O.K. for you to lose sleep? As your PhD draws nearer to the end, the stress will rise, whether you want it or not, and you will get at least few sleepless nights. Is there some medication that can help you with that? A doctor should now that, as well as the risks.
Second, you should look for a potential advisor and talk to him/her. Explain your situation, see if there is something to be done (i.e., give you much looser deadlines), maybe even arrange to meet with both your doctor and your potential advisor together to discuss this. An advisor can point out the potential problems, and a doctor can address them.
Third, what would you do after getting a PhD? In many countries, a PhD is the first real step towards the research career. Such career, while relaxing in some aspects (flexible working hours, for example), is quite stressful in others (paper/conference deadlines, looking for grants, fighting for university positions, your own PhD students, problems in getting results and/or being unable to solve some problem,...). At that phase, you will not be able to have the world adapt to your needs. A journal will not postpone its next issue to wait for your paper, a conference will not be postponed for you, grants will not be just handed to you,... Is this the life you can handle? This is also to be discussed with your doctor (if possible, have someone with such experience along). If not, what does PhD give you and is it worth going for it?
Not to end in such grim tones, there might be alternatives. You can go for a "normal" (i.e., non-research) career, but talk to some researcher(s) and see if you can cooperate (see it as a hobby at first), so that you do some research, but without all the pressure. And, if that works out well, you can always discuss doing those additional steps.
But, do remember: communication is everything. Without consulting your doctor and at least one academic, I don't think you should go for a PhD.