Last year, 425 people died of extreme heat in Phoenix. Stephan Goodwin was one of them. Today, why people who suffer from schizophrenia are more vulnerable to a hotter climate. And, what can be done to better protect them.Read more:Climate change is warming the planet and breaking heat index records across the globe. For people with mental illness, scorching temperatures can be especially deadly. That was true for Stephan Goodwin, a 33-year-old man who spent his last moments of life in the sweltering heat in Phoenix last year. Goodwin had schizophrenia, an illness that is often characterized by  hallucinations and paranoia. One study of heat wave deaths in British Columbia found that 8 percent of the people who had died in the heat had been diagnosed with schizophrenia — rendering it more dangerous, when combined with heat, than any other condition studied.Climate reporter Shannon Osaka recently went to Phoenix to meet Goodwin’s mother, Darae Goodwin, and to better understand why people with this condition are so vulnerable to a hotter climate. Shannon and guest host Rachel Siegel discuss how the physical, mental and social toll the disease takes can exacerbate an already dangerous situation, and what can be done to better protect this population.