Since ancient times, physicians have believed that women are especially vulnerable to certain mental illnesses. Contemporary research confirms that women are indeed more susceptible than men to anxiety, depression, multiple personality, and eating disorders, and several forms of what used to be called hysteria.

Why are these disorders more prevalent in women? Brant Wenegrat convincingly asserts that women's excess risk stems from a lack of social power. He reviews women's social power from an evolutionary and cross-cultural perspective and places mental disorders in the context of...