Coffee and chewing gum are the only habits Ms. Baker allows herself after a stretch of addictive behavior with cigarettes, alcohol and drugs in her teens — experiences that figure in the songs on both of her albums. For the interview, she ordered her fourth coffee of the day: organic, iced, with almond milk.

When Ms. Baker initially released the songs from “Sprained Ankle” online in 2014, she was a student at Middle Tennessee State University, writing music she only expected a few friends to hear. The recordings, made in three days, were stark solo tracks with a handful of overdubs; they often used only a few picked guitar notes tolling behind her voice, as she sang troubled, at times suicidal thoughts. But the independent label 6131 discovered the songs, signed her and issued the album, in mastered form, in October 2015. By the end of the year, Ms. Baker had reached listeners nationwide. Jon Caramanica of The New York Times chose “Sprained Ankle” as one of the best albums of 2015.

“Sprained Ankle,” was a measured cry in the wilderness, a distillation of solitary despair. Just two years later, “Turn Out the Lights” is the work of a songwriter who has resonated with an international audience and who is moving beyond the apocalyptic self-absorption of adolescence. It’s the rare second album that, despite new self-consciousness, stretches beyond an unspoiled debut to reach for even bigger things, with all its passion intact.

“Once we finished recording it, in January, there was a lot of anxiety for me,” Ms. Baker said. “Is it too similar? Is it too different? How can you be afraid of both of those things at the same time?” She laughed. “But I somehow was.”