Did she quit it completely all at once, or did she try to gradually reduce the dose over the course of a few months until finally quitting it totally?
Usually with those kinds of medicine, it messes with the chemical processes in the nerves and cells, to where certain processes are altered or even halted entirely in order to prevent certain behaviors or emotional triggers, etc. (Apologies for a very layman's explanation).
If suddenly this medicine stops being taken, then the previous alterations to the chemical processes in the brain and nerves which have become normalized through long term use of the medicine, will be entirely out of whack and can cause severe reactions as suddenly things which had been repressed by the medicine are overdosing the nerves or brain.
Reducing the dose in small stages, such as reducing it by 1/4th, or even 1/8th at a time, every few weeks, can allow the body to slowly adjust to this chemical change and allow someone to quit taking medicines like that safely.
Of course, it goes without saying one should consult with a doctor on this (just let her go to a regular doctor first and explain what happened and that she wants to quit the medicine, they should be able to give decent advice).
Also, it would help if you could look online about the specific medicines side effects and other things that can happen with long term use and also when one tries to quit the medicine.
You may give the name here as well and we can help you look for this too.
As a general rule, when quitting these kinds of medicines, never quit them all at once cold turkey so to speak, as this often caused severe adverse affects to the body like she experienced.