Though novelists and screenwriters have undeniably made great leaps in their understanding of mental health since the Bronte sisters' depictions of undefined "madness" back in the Victorian era, plenty of progress is yet to be made. Writers still fall back on stereotypes in droves, or else completely neglect to acknowledge that they are writing about an illness. Even when this is not the case, management and recovery of mental health issues are rarely explored. This reflects directly on people with mental illnesses, and it does not help them.
Firstly, it's okay to name mental illness when we write about it. There are writers upon writers who portray mental illnesses, but only discuss this in interviews. One such example is J.K. Rowling, who has stated on more than one occasion that the "dementors" in the Harry Potter series are based on her own experiences with the great lows of Major Depressive Disorder, but this is not mentioned in the series in spite of its potential to provide both solidarity and awareness to sufferers. Similarly, the team of writers responsible for season six of Buffy the Vampire Slayer do not name Buffy's depression in the body of the series itself, to similar effect. The very unfortunate thing is that these two examples are generally sensitive and accurate portrayals of depression, but they never give them the name that identifies them with their audiences. Mental illness is lonely, and by not naming illnesses, we perpetuate this isolation. At best, leaving them unnamed reinforces a taboo which saddles sufferers with an unnecessary sense of shame. At worst, it normalises the behaviours, leaving people less likely to seek help and takes away the opportunity for the relief implicit in being diagnosed with something manageable or even treatable. Simply giving our portrayals of mental illness, their proper names can go a significant way towards reducing feelings of isolation for a short time.
A recognised mental illness is treatable with medication and talking therapies, amongst others, but writers rarely ever explore recovery. Mental illness is not a personality trait and should not exist as such in mainstream media. People experiencing mental illness need to know that those distressing, intrusive, and inexplicable feelings are not permanent. Those same people should not have to find reassurance through The Bell Jar, risking themselves on all of Plath's descriptions of the 1960s approach to treating mental illness and the vivid explorations of the protagonist's suicidal ideation and attempt. It is more than possible to explore these in "gentler" media, evidenced by Call the Midwife's sensitive, well-researched depiction of character Sister Mary Cynthia beginning to recover from her depression. Even in the comedy genre, Suits provides a rare and desperately needed example of a male protagonist undergoing talking therapy to treat a panic disorder. Even short, sensitive scenes in accessible forms of media provide a means for awareness and reassurance, and this can make all the difference to someone in the midst of one of the very lowest lows.
When writing about anything at all, a person has the responsibility to research it thoroughly. In the same way that someone who has climbed the Eiffel Tower should not expect to write a textbook on architecture based entirely on this knowledge, someone cannot write a novel about schizophrenia based on a viewing of Donnie Darko. Like physical disorders, psychological and psychiatric disorders range widely and come with their own sets of diagnostic criteria. This same criteria differentiates schizophrenia, bipolar disorder, and dissociative identity disorder, which writers consistently fail to do, using the terms interchangeably, often to "explain" violent behaviour. There is no excuse for this. The DSM-V is available online, as are stacks and stacks of people's personal experiences on support forums. A writer who ignores the negative symptoms of schizophrenia, such as not talking or struggling to care for oneself, in favour of the positive ones such as delusions or erratic speech, is one who perpetuates widespread misconceptions and stigma for the sake of "dramatic effect." This is a phenomenon I like to call bad writing. Being ill is harrowing and overwhelming, and writers should not worsen this by pretending mental illness is a sure route to violent crime: this makes it comparable to leprosy in the public eye. Sickness is not a showcase. Writers who care about reducing stigma and distress ought to put in the requisite research, and horror writers will find plenty of writing material in the lack of resources for people with mental health issues, if they decide to write about them at all.
The act of listening to the people about whom you are writing will have a huge knock-on effect. People with mental illnesses do not need to be swept under the carpet or misrepresented. They need to have a say in the way other people depict them. Listen and learn. Then, and only then, should you write.