It’s been a dismal season for freshman comedies on the networks, based on ratings. That’s the industry’s general perception, which is unfortunate, because it overshadows some notable efforts to break the sitcom mold. The most promising trend might be called the heart attack — shows that deftly add dollops of emotional depth, feel-good moments and real-world conflicts to their mix of one-liners and pratfalls.

NBC’s “About a Boy” and Fox’s “Enlisted” are good examples of how to weave heart into the fabric of a comedy in a way that doesn’t make you groan and doesn’t scream “Very Special Episode.” Credit the skill of showrunners Jason Katims (“Boy”) and Mike Royce (“Enlisted”) for deftly guiding their laffers along that fine line. ABC’s “The Goldbergs” also has a pleasingly pulmonary touch. This is a welcome improvement after too many years of shows that were inane or too wink-wink clever by half, with no laughs.

But the comedy that has impressed me the most this year is CBS’ “Mom.” The Anna Faris-Allison Janney starrer from the Chuck Lorre/Warner Bros. TV shop has proven its willingness to paint a portrait of a single mother with more flaws than virtues. Faris’ Christy is a recovering alcoholic struggling to earn enough as a waitress to take care of her two kids and battle the questionable influence of her own mother, Bonnie, who was a role model in all the wrong ways but also trying to stay on the wagon now.

In the course of the season so far, Christy has dealt with her daughter turning up pregnant, her dopey decision to sleep with her boss, and her descent into questionable behavior brought on by a bad-influence boyfriend. Then there was the arrest and conviction of her friend (played with sass by Octavia Spencer) for embezzlement, and Christy’s discovery of her biological father who abandoned Bonnie when she was pregnant. Christy’s not exactly Walter White, but she’s no Carol Brady either.

“Mom” was inspired by the desire to examine the notion of redemption for a woman whose life is a mess mostly due to her own bad choices. The series was created by Lorre, Eddie Gorodetsky and Gemma Baker. Faris and Janney easily could have wound up aping “Absolutely Fabulous” — but they didn’t. “Brave” is a word thrown around a lot to describe actors’ work, but in this case, it fits.

With all due respect to the writers, it’s the two leads — individually and through their screen chemistry — that make the show’s tricky balance of funny and serious work. Janney, who is never short of double-entendre zingers, cries after coming to grips with her own relapse into drinking again. Christy hops around on one foot after hurting her ankle because she can’t afford to go find out if it’s broken. Without the heart and the serious comedy chops that those two bring to their performances, the show would be uncomfortably awkward.

“I am so proud of what we’ve been able to do this season in dealing with heavy issues,” Baker says. “It’s not like we had a list of Issues to Tackle, but we went after those our characters would naturally face. Christy can’t be working as a waitress with two kids and not have money problems.”

The question of how far is too far and what might be too maudlin has been a constant focus for the “Mom” writing team, Baker admits. But as they challenged one another to go deep and think about what Christy would face in the real world, they gained insight.

“The more emotional the story is, the easier it is to find the funny around it,” Baker says.

That’s motherly advice worth taking to heart.