Christian Jarrett, ’It is possible to find happiness again after major depression’, https://digest.bps.org.uk/2016/08/24/it-is-possible-to-find-happiness-again-after-major-depression/, Research Digest, British Psychological Society (August 24, 2016).
So what was different about the (…) people who’d had depression but were now fully recovered, compared with those who continued to have problems? The single most important factor seemed to be having supportive relationships. (…) Other important factors were related to physical health, such as experiencing good sleep, being pain free and being physically capable. (…) A promising message from the research was that the duration of earlier depressive episodes was not related to chances of being completely recovered.