Now in its third season, “Celebrity Rehab with Dr. Drew” (9 p.m., VH1) leaves me with more questions than answers. “Rehab” chronicles Dr. Drew, a real doctor, as he counsels the well known or formerly notorious through detox, withdrawal and rehabilitation. The end goal here is supposed to be sobriety. But the means and the medium point to darker motivations.

If you accept the given that Dr. Drew is a doctor and that doctors treat the sick and take oaths to help them and to “first do no harm,” then how could a doctor exploit his patients for publicity, celebrity and money? And how could corporate sponsors help him do it? And why would viewers find this “entertaining”?

If Dr. Drew is to be believed, his charges are very sick people. This season his ward welcomes Mackenzie Phillips, Heidi Fleiss, Tom Sizemore, Dennis Rodman, Mindy McCready, Lisa D’Amato, Mike Starr and Joey Kovar.

Some may contend that the above-mentioned are merely publicity hounds and that they appear of their own free will. But many sick people have to be protected from self-destructive impulses, including the desire to exhibit their illness for money and camera time.

Call me old-fashioned, but even Sizemore has a right to privacy, and a doctor has a duty to protect even Sizemore from his worst inclinations. Instead, Dr. Drew, the so-called addiction expert, appears to be “enabling” him in all the worst ways.

Put it another way. What if Dr. Drew’s cast wasn’t well-known, and presume VH1 merely trolled mental wards for anonymous subjects with “entertaining” symptoms? Would that be so different from this? What’s next? Will VH1 scour the streets and skid rows of America asking us to laugh at homeless schizophrenics? Would it be any less appalling than what goes on here? It would be almost as appalling as “Hoarders,” A&E’s popular showcase for exhibiting and exploiting mentally ill people for ratings and advertising dollars.

• “Planet of the Apps: A Hand-Held Revolution” (9 p.m., CNBC) examines the billion-dollar business of developing and marketing applications for iPhones, smartphones and other hand-held devices.

Like many technology boomlets that preceded it, the “apps” business has a gold-rush feel about it. “Planet” visits with successful entrepreneurs and also explains just how difficult it can be to turn a profit in this field.

• “Chuck” fans who can’t wait for it to return to NBC on Sunday can spend five hours with the hapless secret agent during the five-hour “Chuck” (4 p.m., Syfy) marathon.

Tonight’s other highlights

• On two episodes of “CSI” (CBS), three cases in one night (7 p.m.), Langston and Riley are taken hostage (8 p.m.).

• Alabama and Texas meet in the BCS championship game (7:30 p.m., ABC).