I'm planning to write a sad/horror story where the main character accidentally drowns her little sister. She then gets "haunted" by her little sister every day after that, taunting her and making her feel guilty. I want to reveal at the end of the story that there is no physical spirit, it's all in her mind and that her sister's "spirit" is her own subconscious talking to herself. I'm afraid that this might offend people if I do not portray it correctly. I guess it would be a mixture of PTSD, anxiety, and depression. How would I accurately and realistically make the main character gradually and slowly lose her sanity, but not just suddenly snap?
You should start by creating stakes in your MC's life that are affected by her sister suddenly showing up and throwing her off-balance. Is she in school? Trying to make a sports team or start a relationship with a boy she likes? Invest the reader in something that she cares about, and then slowly introduce her sister's "ghost" to the situation. If the MC is known to be a proper girl and a perfectionist, maybe she has an outburst in the middle of class when she sees her sister at the front of the room next to the teacher. The twists and turns of her descent as a character are a product of both her sister's appearances, her reactions, and then her reactions to those reactions. If she loses it in the middle of class, she's going to be embarrassed and angry at herself for creating a scene and looking so foolish. More fodder for her interactions with her sister, and the cycle continues down to the breaking point. I've read several times that your story is always about death, whether it's professional, psychological, or actual death. In your MC's case, the big question surrounds her psychological death: will she be able to continue her life and achieve her goals? Or will fear of her sister's presence shatter her? Keep us guessing; there are a lot of opportunities to have fun with a story like this!
I'd worry less about potential offense and be more concerned with just doing the thing right. It's a better place to come at things from, imo - with the focus being on fidelity and accuracy rather than a fear of messing up. That said, I'd urge you to first think about what concept you have about sanity. Mental health is a complicated thing and there's not some line beyond which you're 'insane'. The term's not even really used except by the legal system. She's not going to slowly lose her sanity; sanity isn't really a thing. That said, I think you're on the right track with PTSD. I recommend doing a LOT of research on the topic, from credible sources. Wikipedia is an okay place to start as long as you investigate the sources. I also like reading people's person accounts (you can usually find blogs and forums), but I'd suggest you get a working knowledge of the topic first. Disclaimer: I don't have any kind of psych degree nor am I a student, just an autodidact with a vested interest in mental illness. I'd definitely expect her to experience depression and anxiety along with the guilt. I'd expect her to experience flashbacks, which can be the more 'cinematic' flashbacks like you see in movies, or more like reliving it emotionally (more like a panic attack). She would likely avoid things and areas that remind her of the trauma (eg if the sister drowned in the tub, she'd be leery of the bathroom), and forced exposure to these things could trigger her - flashbacks and panic attacks would be likely. (So would nightmares.) Repeated triggering would take its toll on her mental state, and could be a way to get the slow decline you're looking for. Now, hallucinations or delusions aren't really a hallmark of PTSD, which is a complication. You'd need to find a way to make flashbacks feels like a haunting. EG, every time she goes by the place her sister drowned, it makes her panicky and she's stricken by guilty intrusive thoughts, which makes her feel like her sister is there punishing her / talking to her. Eventually this could lead to a breakdown, but I cannot stress enough that this isn't her 'losing her mind' or 'going insane' - it's just a breakdown. She mind be incomprehensible or unresponsive for a while (especially since thinking you're being haunted is added stress) but she would in all likelihood recover. It's not gonna be all strait jackets and rubber rooms from here on out for her. One important thing: young kids tend to not develop PTSD as we understand it, because they emotionally process things differently. I'm assuming your character is more teenaged and it's not an issue, just wanted to bring it up.
I love reading and writing stories that have an element of madness. Here's a few things I've learned: The most important thing is to make it gradual. There should be no point in your story that you can point and say "this is where he loses it." Losing your mind is a very gradual process and a compounding one. You don't just lose touch with reality, it simply gets replaced with your own piece by piece until there is nothing left real. It can't happen so slowly though that you can recognize it. I suffer from hallucinations, but I can quite easily determine that they aren't real because I've heard them for years. Having a support system also makes it easier to stay grounded, so in your story you might want to remove that, introduce an antisocial aspect to the character to make it easier to remove them from reality. Hallucinations tend not to be circumstance-specific, they tend to be primal: death, danger, existentialism... The anxiety from the madness tends to compound and cause a snowball effect. At first you may be anxious about something hung real, which causes your grasp of reality to flicker, but after a while, your anxiety is caused by the realization that you're anxious.
I am not trained in analyzing people, but I do have some experience. My wife used to drive patients for their meds and the stories were all captivating. I think a lot could be done with that premise. First, the person losing it never believes they are the ones slipping into darkness. It is usually preceded by some tell, like a quirk or OCD. The other thing she noted was they all seemed very bright. You could never tell by any short visit anything was wrong. But every once in a while the difference would shine through.
Maybe it's just me, but I would find your proposed ending a bit disappointing. I think the ghost of her little sister could be far more interesting than it-was-all-in-her-head. It's just that we've all seen this before, and every time it's always a letdown for me. I think there's nothing wrong with letting readers think your MC is going crazy because I'm sure that will cross their minds, but I bet you can deliver something better, more original and less predictable. Good luck.
I actually manage these conditions in my daily life. None of these on their own or mixed together will cause the type of psychosis you are describing. A lot of neurological and psychological conditions cause all manner of hallucinations that persist as some alternative reality for the sufferer. These ain't it. And if we are talking about psychosis, it's rarely a smooth curve up or down the sanity scale. There are lucid moments and good days, meds that stop working for no reason, events that exacerbate or alleviate part of the psychosis, it's more of a jagged graph than a smooth slope. I don't want to start throwing around cool disease examples, but the people I've personally known who displayed these symptoms suffered from dementia and schizophrenia, respectively. I wouldn't necessarily find this story offensive, depending on how it's done, but there's a huge potential for icky tropes. I actually wrote a whole thing about the portrayal of mental illness in pop media, maybe it can be useful. Honestly I personally feel that a gradual illness progression is best reserved for long-form prose, because any steady decline benefits from change in small increments, and I don't think you can get around the fact that these things just take time. But I'm definitely not saying it can't be done, just that I haven't seen it. (Young children accidentally killing a sibling is frighteningly common, actually. There's a lot of personal stories online you can use for insight. I know I read about a person coping with it just recently, I'll see if I can find that story again.)
Well, I've looked around and I can't find the story I was thinking of amidst all the other news stories about dead children, and I'm very sad now. Good news! There's no lack of case studies. Are you a gamer by any chance? Or willing to try casual-ish video games? Because the more I think about this topic, the more I want to recommend The Sexy Brutale as a ridiculously cool and inventive example of what we're talking about here. If you're even a tiny bit inclined to try it, I think there's a wealth of inspiration for you there.
If you put a label on it, people may be apt to say, "That's not what it's like!" So I wouldn't call what she has by a name. That lends itself better to horror, I think. Instead, I'd just show what she goes through. In horror, you can get away with showing the progression to insanity in a number of ways. Some movies do it well, others not so much. Here's a list I came up with: Spoiler: Characters in these movies go insane Fight Club The Machinist Land of the Blind Shutter Island The Number 23 Below Sphere Shutter I might also suggest a less direct ending. Instead of resolving the end neatly, she could be diagnosed with something, but then experience a vision or some other event that fits with the experiences she's had, only to find evidence to suggest it's real. Here's an example from, surprisingly, "The Polar Express:" Spoiler The main character wakes up Christmas morning, having had a "dream" of going to The North Pole. For a moment, he's led to believe it was just a dream, but then he receives a bell he recognizes from Santa's sleigh. He then knows what he experienced was real. Modify that for the feel of your story, and it could make for a better horror ending. Something like, "She opened her eyes. She was okay. Sweaty and shivering, but she was okay. The note hadn't been real. It was just a nightmare. She got up and splashed cold water on her face, and almost managed a smile. On her way out of the bathroom, she stopped cold. A folded piece of paper sat on the nightstand, covered in water stains. Trembling, she unfolded it and read: "Hi sis. I'm still here. Love you." The End. First draft quality, but you get the idea, hopefully.
Keep it gradual, keep it subtle. Massive 'snaps' can easily come off as being overplayed. It needs to be a long running spiral that, more than likely, the character is not even aware of. She could have long conversations with her sister, forgetting entirely that she is even dead. It could either be a fully imagined conversation or a memory of one. She could be seeing an apparition of her out of the corner of her eye, or simply an indistinct apparition that stays with her. Not something interacting with her, but just something that is there regardless. Her 'sister' can start telling her things that make her paranoid of others or react just 'wrong' in what would be a normal situation. However you go about it though, keep it subtle to avoid it becoming a parody of itself.
Writing something like this would traumatise me! I'd end up just as crazy as the character. But try to make it as gradual as you can. With small counted steps each chapter. Choosing intelligently how much you should write about the weird feelings she has. Until the end, just extreme tension about how she feels. Try reading and learning about how tension and suspense is created. Also you can maybe make her try to commit suicide, hurt herself or others at some point. Have her do what mentally ill people may do. And don't forget to smile!
I think the answer to your question is the little details. Like trying to relate the visions your character is having to what is really happening. Like if she thought she was talking to her dead sister, what was she doing instead? talking to a wall? talking alone out loud? Make each appearance of the dead little sister to have a consequence. Think how those visions would impact your character emotionally, like how the symptons would produce more secundary symptons. Leave little cues throught the story that what she is experiencing isnt real, so that at the end the reader gets a "ohhhhhh that makes sense" moment instead of having it come from nowhere. That's my two cents.
Try loosen speech patterns or inner monologue patterns, adding hesitation markers like ellipses, towards the end where cognitive awareness and sanity are very deteriorated - start leaving out simple filler words like "I","he","she","we","is", etc.
