"Of course, we can become psychologically unhinged for many reasons that are common to all, like personal traumas, social upheavals or biochemical imbalances in our brains. Modern science has begun to reveal these causes. Whatever the trigger, however, the ill individual and those around him invariably rely on cultural beliefs and stories to understand what is happening. Those stories, whether they tell of spirit possession, semen loss or serotonin depletion, predict and shape the course of the illness in dramatic and often counterintuitive ways. In the end, what cross-cultural psychiatrists and anthropologists have to tell us is that all mental illnesses, including depression, P.T.S.D. and even schizophrenia, can be every bit as influenced by cultural beliefs and expectations today as hysterical-leg paralysis or the vapors or zar or any other mental illness ever experienced in the history of human madness. This does not mean that these illnesses and the pain associated with them are not real, or that sufferers deliberately shape their symptoms to fit a certain cultural niche. It means that a mental illness is an illness of the mind and cannot be understood without understanding the ideas, habits and predispositions — the idiosyncratic cultural trappings — of the mind that is its host."