More than her wild abandon or her loopy and magnetic stage presence or the virtuosity of her band, those lyrics are central to the Nancy Mroczek PhD experience. Occasionally she’ll cut loose with a nonsense song like "Hoochie Koochie" or a straight-ahead riff-rocker like "Baby You Love Me," but by and large the songs Mroczek sings are about sociopolitical issues she’s always held close to her heart: animal cruelty, environmental despoliation, man’s inhumanity to man, the depredations of corporations.

"The thing I care about most is animals in laboratories," Mroczek says. "Secondly, I care about the environment. It literally breaks ... my ... heart. When [Exxon] Valdez happened, that broke me, I think. And everything’s just been worse from there. But I care more about the animals. Because they have no part in the destruction. I love them, and I hate to see it happen to them."

Those last words speak volumes. As Mroczek expounds on her music, her profession, and her world-view, what soon comes into focus is a person imbued with empathy. She’s earnest, she’s passionate, she has a strong sense of justice, but she’s not judgmental. And when Mroczek wants to express herself, she does.

But it’s also true that her profession and her passion can make for some surprising juxtapositions. Just look at the home page of her Web site. There’s a photograph of Mroczek the psychologist, smiling demurely, dressed in a professional-looking suit, standing before an ivy-covered wall. Then click on the navigation bar that reads "Live Performances." There’s a photo of Mroczek the singer, in thrall to the demon power of rock and roll, stripped down to a white tank top, on all fours and screaming blue bloody murder into a microphone.

Still, she seems genuinely taken aback when it’s suggested that the type of music she plays might be at odds with what many people, just to look at her, might expect. "Oh no, it’s me," she insists. "If anything, Berklee people will be more into funk and jazz. I’ve had some drummers whose arms ached because they weren’t used to that style, even though they practiced all the time. No, it’s always been my expression, definitely."

"I’ve always been into music," she continues. "Especially rock music and certain types of soul music. Certain songs of the Sex Pistols grabbed me. Nirvana grabbed me. Current rock music grabs me too. The Kid Rock song, with Sheryl Crow? I really like that song. My band won’t play it, ’cause they don’t like Kid Rock. But I’ve done a Backstreet Boys cover. ‘I Want It That Way’? That song grabbed me big-time." She makes a little grabbing motion at her heart. "I mean, I’m a sucker for a song. One time I did ‘Ain’t Talkin’ About Love’ by Van Halen. And then I segued into ‘I Want To Know What Love Is,’ and the crowd just went out of their minds!"

She spouts off an encyclopedic array of influences. Roy Orbison. Aretha Franklin. The Stones. Lou Reed. Patti Smith. The Smiths. Wardell Gray. John Coltrane. Neil Young. Thompson Twins. Talk Talk.

Though she’s been known to sing a jazz standard or two, these days, when Mroczek struts on stage — at T.T. the Bear’s Place or at the Linwood Grille, Upstairs at the Middle East or at O’Brien’s or the Abbey Lounge, where she’ll be this Friday — she knows only one word.

"Rock. Rock. Definitely rock. Because that’s how I feel. I’ve had some jazz gigs, singing jazz standards. And that’s pure enjoyment. But when you do rock, it’s like trying to get through to people. Not to convince them, but just to get through."

Mroczek sees rock and roll as an easily apprehended language with which to communicate her feelings about human beings and the things we do to ourselves, to each other, to animals, and to the earth. She sings her songs simply because she feels compelled to. But if audiences walk away enlightened, all the better.

Take an impassioned cri de coeur like "Planet Earth," in which she sings about "radiation ... across our nation ... for corporation" before coaxing the band into a lull, then goading it on to a frenetic crescendo, and screaming, "What about earth? You’re ours! All ours! No destruction!" as if the very survival of the globe depends on it. As another song uncoils into a discordant pile, she riffs reflexively: "Let the animals go! How could you do that to anything that lives? How dare you do that?!"

"Nancy’s lyrical style is pretty direct," says Karz-Wagman. "I think it’s cool that she’s singin’ about political issues and stuff that she’s concerned about. She has these parts in the songs where we’ll just stand there, just letting the notes ring, and she’s just talking to people, y’know? She stresses about talking to the kids. She’ll say [to the band], ‘Don’t be too loud here so the kids can hear me talkin’.’"

"I want ’em to have a good time. I want ’em to get roused. I want for them to get the spirit of what I have to say," Mroczek says. "I really am not into imposing my message on anybody. I really believe it, but all I want is that they’d consider it and let it in and toss it around and cause it to be some stimulus."

"She has something she wants to say, and she’s not afraid to get up and say it," says Ben Taylor, an erstwhile Bostonian (late of the band Beat Down Sound) who played impromptu with Mroczek one night years ago when they shared a bill at the Middle East. "She definitely has musical skills. She has good ears. I’ve seen her play with a bunch of bands, and she just jumps into improv situations."

Taylor also avers that there’s a community of Mroczek admirers out there, trading her videotapes (for sale on her Web site) like samizdat, spreading the gospel via VHS.

Lisa McColgan, who performs with the Boston Rock Opera and drums in the band Scrapple, puts it most eloquently. In 2000, in an online diary (lisamcc.diaryland.com) that she still keeps, she confessed to "rapidly becoming [a] devoted disciple of Dr. Nancy.

"[She] kicks major ass," McColgan wrote. "Depending on how you look at it, [she’s] either one crazy dame or the Prophet of Our Times. I confess that I once belonged to the former school of thought ... [but] I cannot quite pinpoint the exact moment that I started to genuinely admire Dr. Nancy. I do know that the admiration stems primarily from what I view as her remarkable sincerity. Anything is brilliant if it’s sincere, in my book. There is nothing forced or staged or pretentious about Dr. Nancy. She radiates this sincerity, and people respond to it."

FRANKLY, I THINK more like their generation," says Mroczek. "Where I’m coming from philosophically, and the way I really feel inside, I always feel more like the younger people do than I do my own age group. I’m not a bourgeois kind of person. There’s a part of me that likes to go to chill to some good jazz music in a nice lounge, with people who are achieved. But basically, at heart, where I’m coming from always seems to be the current thing coming up, the Zeitgeist."

All the same, she’s not blind to the fact that she’s got a few years on her band members and most of her audience. But, she says, "I don’t think about the age thing. I’m very aware that it’s thought about. But I don’t think it should be thought about."

It’s that kind of youthful tenacity, in part, that keeps her getting club gigs more or less every month in a town where it’s notoriously hard to do so. Since 1998, Nancy Mroczek PhD fliers have been fluttering on bulletin boards all over clubland in Greater Boston on a regular basis.

Lately, though, attendance at Mroczek’s gigs has been flagging. "I’ve booked her a lot over the past three years," says Middle East booker Chris Jackson, "and you never know who she’s gonna play with or what she’s gonna do. But the past couple gigs, no one really came. I think she’s very intriguing, I just don’t really know how to [reconcile] that with a paying public."

At Mroczek’s last Middle East headlining performance, there were fewer than 20 people in the audience. To be sure, it was a Monday at midnight, and it was raining. Still, Jackson sees something else at work. "I really think she could stand to put out some more recordings," he says. "She doesn’t really have any records out. That would really give people an excuse to come see her. Being in a band myself, I know you can only really ask people to come out and see you so many times on the current record."

That’s something Mroczek wants to remedy. But it’s hard to find the time to get record deals and do publicity, what with her being a professional psychologist and all. "I wish I had someone to manage it, who could say, ‘Do this, do that, do this,’" she says. "I need an agent. I really want an agent. That’s what I need."

Meanwhile, Karz-Wagman is trying to get the band noticed. "We had a recording session, and we’re trying to get a lot more tracks done. Because she has so many songs."

He believes in what Mroczek is doing, and thinks others would too if only they could get past their preconceptions and see her music for what it is. "It’s definitely phenomenal," he says. "I feel like it’s a pretty marketable thing. We’re a good band, and Nancy is doing this with no gimmicks, y’know?"

"I just wish more people were paying attention and coming to the shows and that I could make more songs and do more music and be even freer and more open in my expression," Mroczek says. "That’s what I would like. I’d like to be doing this as a way of life. And I’m totally prepared. I’ll never give up [psychology]. It’ll always be me. But as far as not having clients in a given week or month? To just be touring or something? I could do that. I could really do that. I’m trying to clear the decks so my life would be wide open for me to be able to do that."

Meanwhile, Nancy Mroczek, PhD will keep singing her songs.

"She’s one like no other," says Joe Caputo. "Anyone who’s interested in something they can’t see anywhere else should be interested in seeing her."

And you can, for just a nominal cover charge.

Nancy Mroczek PhD perform at the Abbey Lounge, in Somerville, on June 13. Call (617) 441-9631, or visit mroczek.8k.com. Visit www.bostonphoenix.com/Bost_mp3 to hear MP3s of her songs. Toward a Quality of Life airs Wednesdays at 8 p.m. and Thursdays at 1 p.m. on BNN 23. Mike Miliard can be reached at mmiliard[a]phx.com