Mariam, this sounds natural and clear as it is. An alternative is:
After his suggestion at the 1936 II Congress of Psychiatrists and Neuropathologists to exempt psychopathic persons from criminal responsibility, he was accused of counter-revolutionary activity, even despite his outstanding achievements in the Soviet study of forensic psychiatry.
I think both work. The option connects his action (suggestion) and the response (accusation) together. It depends on the preceding and trailing sentences.
In some ways I would err towards the way I suggest, but this gets down to context and personal choice of expression and writing style. This way, the "Despite outstanding...." clause is placed in a trailing position of secondary contribution to the main point of the sentence. This sounds like a very interesting subject!