I was certainly going the right way for a stroke when I left Paris. I paid for it nicely afterwards! When I stopped drinking, when I stopped smoking so much, when I began to think again instead of trying not to think - Good Lord, the depression and the prostration of it! Work in these magnificent natural surroundings (Arles) has restored my morale, but even now some efforts are too much for me: my strength fails me...
Further Letters of Vincent Van Gogh to His Brother, 1886-1889 (ed. 1929)