welcome to HealthcareMagic
Since you are on Citalopram
you may not experience the withdrawal symptoms
much.As far as using nicotine patch
is concerned you can use it because if you are smoking
then you are already combining nicotine with citalopram.I would suggest you to stop smoking without using nicotine patch because please understand it is like going from one addiction to another so it is not beneficial.Stopping smoking is difficult but if you WILL then you can.
All the best.