Given Lindsay Lohan’s latest bout of bad behavior it’s hard to tell where the acting begins and the real-life drama ends in the graphic thriller “I Know Who Killed Me.”

Lohan, who recently turned 21, was arrested this week for driving under the influence of alcohol only 11 days after leaving rehab. The paparazzi darling pulls a Dr. Jekyll and Mr. Hyde as Aubrey Flemming, a popular high school senior who goes missing.

Aubrey has everything a girl could want: an attractive and attentive boyfriend, early acceptance to Yale University and talent as both a pianist and writer. Everything she owns is shrouded in blue, from her room to her car, a contrived color scheme meant to indicate her purity and innocence.

All that, of course, is shattered when she disappears for several weeks and is feared dead. A serial killer with a penchant for hacking off the limbs of victims is on the loose, and the film leaves nothing to the viewer’s imagination.

Miraculously, Aubrey is found alive by the side of a road. The teen, however, insists her name is Dakota Moss, and that she supports herself through exotic dancing and other unsavory means because of her mother’s crack habit.

This is not the first time Lohan has played a dual role. Remember the remake of “The Parent Trap,” in which she played an English-raised girl and her spunky American twin sister?

It is clear from the opening scenes of this film that the focus is on seeing Lohan hyper-sexualized and tortured, not on her acting ability.

As Dakota fights with authorities and Aubrey’s parents (Neal McDonough and Julia Ormond) lengthy montages of her working the pole at a strip club takes the place of actual plot or character development.

Next to stage and screen veteran Ormond as Aubrey’s distraught and frustrated mother, Lohan’s attempts to portray gruffness and anguish are as substantial as cardboard.

Does Aubrey have amnesia? Does she have a look-alike? Is it a dream or one of her short stories? Frankly my dear, I don’t give a damn.

“I Know Who Killed Me” feels incomplete and campy. Perhaps this film needs a stint in rehab.

At AMC Loews Boston Common, AMC Fenway Stadium and suburban theaters.