The remarkable Blücher was the major influence in the successful 1814 campaign in which eventually the Allies occupied Paris but he did have problems. At one stage after the 1806-7 defeat of Prussia by Napoleon he suffered a breakdown, a side effect of which was to have hallucinations about giving birth to an elephant!
In 1814 Blücher had another although less severe breakdown but fortunately recovered to be part of the entry into Paris, which led to Napoleon’s first abdication.
The 1813 and 1814 campaigns are not often reported on as they did not concern the British but both were fought by the fragile alliance of Russia, Prussia and Austria. They are very interesting and particularly well covered in Dominic Lieven’s book, “Russia against Napoleon“.