Like most things involving fictional detectives, it started with Sherlock Holmes. Or maybe it started before Holmes with Edgar Allan Poe's C. Auguste Dupin. I'm talking about the detective, amateur or professional, who is brilliant but eccentric and troubled. He or she is a committed and gifted investigator, but the gifts come with serious baggage - like deep neuroses or some type of addictive and destructive behavior. Over the last 20 years or so, it's been as true on television as in crime novels and stories. Among a few of my favorites of this type: Robbie Coltrane's Cracker, an inveterate gambler, heavy drinker, and chain smoker; Helen Mirren as Jane Tennison, who's not eccentric or odd but who as the series progresses uses alcohol more and more as a crutch; Idris Elba as the dark-souled and violent John Luther. The current Sherlock, of course, has played up the neurotic qualities of Holmes to the nth degree, at times presenting him as an outright mess, though he's as sharp as ever at solving crimes. Other examples abound. And perhaps it's the familiarity of the type that has led television crime writers to take the next step and create investigators who are not merely eccentric or flawed but gripped by psychological maladies. As they do their jobs investigating cases, they have to contend not only with the difficult world around them, but also with whatever their mental condition happens to be.
The series Hannibal on NBC gave us a Will Graham who gets deeper into imagining and visualizing the killings he investigates than any Will Graham we've seen or read about previously. He suffers from encephalitis at one point (though nobody discovers this for awhile) and winds up institutionalized. The show takes us past the cliche of the investigator who shares enough of his serial killer quarry's darkness to understand it and thus catch his prey. Hannibal starts there, with Graham's ability to empathize, if you will, with a serial killer, his ability to think and feel as a serial killer thinks and feels, and then the show goes into a different psychological realm entirely. You don't always feel certain that Graham will return from the realm of derangement he has the ability to access. In fact by the show's end (assuming it is the end and doesn't return anywhere for a fourth season), a part of Graham's mind may be permanently damaged, something his nemesis Hannibal takes pride in having contributed to. What happens with Graham, though, is progressive. He starts out as the brilliant but eccentric investigator who has unique talents, but because of what he undergoes pursuing and interacting with Hannibal, he slides into an area along the fringes of madness. In the show, over the course of three seasons, we see him change.
Not so with London DI John River of the British series River. The show stars the great Stellen Skarsgard as a police detective who hears voices in his head and has whole conversations with people he's known. He even converses with long dead historical figures. This is not a condition that comes upon River during the course of the series; it's the show's basic premise.
The person John River sees and talks to the most is his former partner, who was murdered. She was both his partner and a most sympathetic friend. Though extremely good at his work, John River can experience his visions without warning, at almost any time. It's no secret that he has these visions, and his superior officer demands he undergo a psychiatric evaluation, expecting River to fail it and be taken off the force. But what becomes clear to both his psychiatrist, some of his colleagues, and the audience is that River relies on his voices to cope. The show's creator and writer, Abi Morgan, has come up with a character who is a starkly original variation on the melancholy, middle-aged, gruff cop who has trouble connecting with people. But instead of holing up in pubs (like, say, Inspector Morse would do), he communes with people not there. His condition becomes a metaphor for how to deal with and endure loneliness, and it also gives him a way to mourn his ex-partner. By talking to her, he works through his grief. As such, there's nothing about his mental health issues that strikes the viewer as exploitive or cartoony, and despite his unusualness, he quickly becomes a character you can relate to. He's an original creation, John River, and I for one hope he comes back for another season. What's fascinating, as Stellen Skarsgard has noted, is that River's condition "doesn't really exist as we know it. It's a combination of problems, because he's not like people who hear voices - they're usually schizophrenic and lack empathy and he does not. But it doesn't make it less truthful."
Marcella, which I just finished watching, is an eight part British series centered around London detective Marcella Backlund, played by Anna Friel. When the series begins, she has been off the force many years, but she rejoins it after a detective on the murder squad visits her to consult her about a string of murders that seem to replicate murders that she investigated, but never solved, eleven years earlier. Marcella is a hard-driving, very focused and observant detective who clearly has a high IQ. She also happens to be a person with an explosive temper, and when she loses that temper, if she's under great stress, she goes into fugue states in which she does things she can't remember later. In those fugue states, it becomes apparent, she's capable of just about anything, including, perhaps, deadly violence.