On Showcase's new Canadian cop show Shattered, the title refers in part to the brain of Callum Keith Rennie's police detective Ben Sullivan who suffers from Dissociative Identity Disorder, the disease formerly known as Multiple Personality Disorder (and incorrectly known as schitzo). The fact that this homicide investigator could inadvertently flip to another personality at any given moment -- as happens in the premiere when a more ruthless alter-ego arises, resulting in an unarmed suspect's death at the hands of his totally freaked out new partner -- gives Shattered an edge lacking in most police procedurals. Most... but not all. 

Shattered is actually the latest in a line of pedigreed detective dramas to feature mentally unbalanced cops. So let's take a look at the police lineup:

Norman "Stan" Stansfield, The Professional (1994)
Gary Oldman has played plenty a whack-job in his day, but his psychotic DEA agent in French director Luc Besson's mob movie was a perfect counterpoint to Jean Reno's reserved hit-man Léon and Natalie Portman's precocious protege Mathilda who swore vengeance after Stansfield gleefully murdered her entire family, whistling Beethoven all the while.

 

Adrian Monk, Monk (2002-2009)
Technically, Tony Shaloub's Emmy-winning character isn't a cop -- at least not anymore. After his wife died in a car bombing, homicide investigator Monk went crazy. But a helpful kinda crazy. His obsessive-compulsive disorder helps him fight crime, albeit awkwardly. Monk's OCD makes him pay extra-special attention to details, a detail which compels the San Francisco police department to hire him on as a consultant even though he has 312 phobias, including milk and ladybugs. (Though to be fair, milk is kinda gross).

The Lieutenant, Bad Lieutenant (1992)
Though quasi-remade by Werner Herzog last year with Nicolas Cage stepping into the crazy cop role in Bad Lieutenant: Port of Call - New Orleans, it's hard to compete with the original's savagely raw performance by Harvey Keitel, as a cop consumed -- and, well, shattered -- by his base impulses. Ungleefully indulging in gambling, drugs, drink, sexual abuse and murder, he's eventually driven over the edge while investigating a nun's rape. 

Det. Robert Goren, Law & Order: Criminal Intent (2001-2010)
Vincent D'Onofrio's unbalanced investigator comes by his apparent mental illness naturally, with his mother institutionalized in an insane asylum for paranoid schizophrenia and his alleged father a serial killer. (Oh, and his nephew is bipolar). Though Goren usually gets away with his so-called eccentricities, he was briefly suspended and given a psychological fitness evaluation.

Detective Martin Riggs, Lethal Weapon I-IV (1987-1998)
Though he'd become a movie star with Mad Max, Australian actor Mel Gibson ascended to superstar status on the back of the Lethal Weapon buddy cop franchise. Narcotics officer Riggs was suffering depressed after his wife's death -- he was the lethal weapon of the title -- and though his craziness was played for laughs, his full-on suicidal tendencies also gave the first film a shockingly dark streak. Plus, y'know, it must have been really hard for Gibson to play a crazy with anger issues.