There's a song on Aimee Mann's new album called "Philly Sinks."

The Mental Illness track doesn't concern plumbing in the City of Brotherly Love. Nor is it about houses being sucked into the earth in the Logan section of the city.

"It's about a guy who is a sober alcoholic," the singer-songwriter says on the phone from Los Angeles. She is to play Friday at the Keswick Theatre in Glenside. "Now that he doesn't drink, he has issues with women. If he's going down, you're going down, too."

The "Philly" in the title refers to the city of birth of the toxic individual, one of many sad sacks depicted on the 11 quietly lovely songs on Mental Illness. "It's his nickname," Mann says. "I got that from a boxing gym, where they call everybody from the town you're from." (Her 2005 release, The Forgotten Arm, is a concept album about the Sweet Science.) "Once you leave Philadelphia, that's your identity."

Mann, 56, grew up in Virginia. After attending the Berklee School of Music, she made her name as leader of Boston band 'Til Tuesday, who scored one big 1980s radio hit with "Voices Carry."  Mental Illness, produced by Jonathan Coulton, is the ninth solo album she has released since 1993, not including the soundtrack to the 1999 Paul Thomas Anderson movie Magnolia, which featured several of her songs. (She also plays a nihilist with nine toes in the Coen Brothers' 1998 movie The Big Lebowski.)

"The seedy underbelly of Los Angeles" is explored in Mental's "Patient Zero," which makes reference to Carmen Sternwood, the carefree killer in The Big Sleep. "I was writing about someone coming to Hollywood and encountering this world of blackmail and backbiting and decadence, and I kept thinking of Raymond Chandler."

Mann is married to Michael Penn, the songwriter who also had one big hit -- with "No Myth" in 1989 -- and has gone on to scoring movies and TV shows like Masters of Sex and Girls. Before Mental Illness, Mann branched out with The Both, a power trio she cofronted (while playing bass) with Jersey rocker Ted Leo. They headlined the first show in 2013 at the reopened Boot & Saddle in South Philly.

After that departure, the excellent Mental Illness sounds very much like a minimalist Aimee Mann record, playing to her strengths with carefully shaped, disconsolate songs marked by sharp wit and enticing melody.

That's by design. "It's partly because I'm coming off a project that was a rock band." (Mann hopes to continue to work with Leo.) "But another thing was: Look, if nobody buys records anymore anyway, then I really don't have to think for one second about what would sell. ...  So I felt like now I can do whatever I feel like doing."

The title came about when Coulton, who will open the Keswick show, joked that that was what Mann's failed-relationship songs are really about. "That really made me laugh," she says. "Because it's true, a lot of them are about mental illness, or at least severe dysfunction." Her character sketches are usually composites of real people. "As soon as you start writing, you have to change details, or invent details to make it more real even."

In October, Mann recorded "Can't You Tell," a song written from the perspective of a presidential candidate who doesn't really want the job but is obsessed with "winning." She's sorry that the song, which was a standout on the 30 Days 30 Songs protest project, was completed too late to be included on the album.

Other than that, Mann couldn't be more pleased with the finished product. When she was a guest on Marc Maron's WTF podcast, the host suggested that Mental Illness was her best album.  She's inclined to agree.

"The songs are finished in a way I like them to be finished," she says. "Paul Bryan did a great job with the strings. It's exactly how I wanted it to sound."

Aimee Mann with Jonathan Coulton, at 8 p.m. Friday at the Keswick Theatre, 291 N. Keswick Ave., Glenside. $29-$49, 215-572-7650,