Thursday, 8.30pm, Bio A tough as nails series about staging interventions in a desperate, last-ditch effort to save the lives of people severely addicted to drugs, or in some cases with compulsive disorders. It’s not pretty. Tonight you’ll meet Tiffany, a former beauty contestant now on the road to ruin. ‘‘ She used to be such a beautiful person, now she looks like the walking dead,’’ sister Megan says. Tiffany is into what’s known as polysubstance abuse, though her main addiction is methamphetamine. This means she ingests a variety of drugs including benzodiazepines and GHB (an anaesthetic known on the street as ‘‘ fantasy’’) at the same time. Tiffany has agreed to be in a documentary about addiction but doesn’t know she will soon face a classic intervention staged by concerned family and friends, orchestrated by one of five specialists in the field. She is furious and feels betrayed. ‘‘ All of you lied to me,’’ she yells. But before we get to the intervention, via interviews to camera, many of them tearful, the program offers insight into the pain and distress suffered by those close to a person whose addiction is out of control. The intervention, when it comes, is emotional but calmer than you may expect, a testament to a family’s unconditional love.