To a remarkable degree, he coped successfully with "black dog," as he called his depressive spells. He sought flamboyant, stimulating, zestful company.
In a profound sense, he himself always remained the underdog. All his life he suffered spells of depression, sinking into the brooding depths of melancholia, an emotional state which, though little understood, resembles the passing sadness of the normal man as a malignancy resembles a canker sore. The depressive knew what Dante knew: that Hell is an endless, hopeless conversation with oneself. Every day he chisels his way through time, praying for relief. The etiology of the disease is complex, but is thought to include family history, childhood influences, biological deficiencies, and -- particularly among those of aggressive temperament -- feelings of intense hostility which the victim, lacking other targets, turns inward upon himself. Having chosen to be macho, Churchill became the pugnacious, assertive fighter ready to cock a snook at anyone who got in his way.
William Manchester
The Last Lion: Winston Spencer Churchill: Visions of Glory 1874-1932