"Depression is the flaw in love. To be creatures who love, we must be creatures who can despair at what we lose, and depression is the mechanism of that despair. When it comes, it degrades one's self and ultimately eclipses the capacity to give or receive affection. It is the aloneness within us made manifest, and it destroys not only connection to others but also the ability to be peacefully alone with oneself.
Love, though it is no prophylactic against depression, is what cushions the mind and protects it from itself. Medications and psychotherapy can renew that protection, making it easier to love and be loved, and that is why they work. In good spirits, some love themselves and some love others and some love work and some love God: any of these passions can furnish that vital sense of purpose that is the opposite of depression. Love forsakes us from time to time, and we forsake love. In depression, the meaninglessness of every enterprise and every emotion, the meaninglessness of life itself, becomes self-evident. The only feeling left in this loveless state is insignificance," – Andrew Solomon.