President Trump is often called a narcissist—and experts have debated that diagnosis—but many other presidents weren't exactly paragons of mental well-being, the BBC reports. Presidents from John Adams to Theodore Roosevelt to Bill Clinton have been called mentally ill, and that's not just on the campaign trail. "The pressures of such a job can trigger issues in someone that have been latent," says Jonathan Davidson, who led a 2006 Duke University study into the psychological health of presidents. "Being president is extremely stressful and nobody has unlimited capacity to take it forever and ever." That study found Wilson and James Madison probably had depression, while Roosevelt and Adams had bipolar disorder. For more: