This week's assessment is from Katrina. She's writing a romantic comedy set in present time about Marnie*, a 20-something who grew up in the special education system even though her IQ is slightly above average. She doesn't correctly predict cause-and-effect outcomes, so she learns things the hard way, and she rarely sees other peoples' perspectives unless she stops and makes a specific attempt. Her parents are deceased, and she has a genius older brother is basically a stranger and an overprotective older sister-cum-mother.
* Names have been changed to protect the fictional.
Katrina wants to know: What makes ordinary life so difficult for Marnie? (A diagnosis, if you will.) What would result in her lacking common sense and struggling to learn street smarts, but paradoxically learning certain types of facts easily and quickly? I need to know why she is this way so I can have a more clear understanding of what she can and cannot do.
This was a tough one, Katrina, and I'll tell you why: I couldn't find a single diagnosis that I'd be comfortable giving this character the way you have depicted her. That tells me one of two things: either I'm in need of brushing up on my diagnosing skills, or your character isn't quite feasible at this point.
Her delay in cause-and-effect reasoning doesn't mean she fits into a developmental disorder diagnosis. In fact, I'd say she doesn't, because she's a way more high-functioning adult than most of the diagnoses on that spectrum (like Autism, Asperger's, Pervasive Developmental Disorder, etc). And most all of those diagnoses require a significant social delay which either Marnie doesn't have or you didn't mention.
I looked into diagnoses for her odd, eccentric behaviors, but she doesn't fit anything like Schizotypal Personality Disorder or Schizoid Personality Disorder.
You mentioned maybe adding a savantism aspect to her character to account for her ability to learn certain things super fast. I did a post here on savantism, but that condition would have some significant challenges for the person to overcome that you don't list Marnie as having.
Maybe she gets overstimulated and has difficulty processing what she needs to do at those times, which might make her seem incompetent to those who witness her in that situation. I considered adult ADHD, and I suppose you might want to Google it to see what you come up with.
However, I suppose a diagnosis of Amnestic Disorder Due to Head Trauma could fit if you could pinpoint her symptoms as the result of memory loss due to a Traumatic Brain Injury. According to what research on the internet I could do with limited time, a Traumatic Brain Injury wouldn't have affected her IQ. (Click here for more info.) However, for her to have the condition above, the injury would have had to impair her ability to learn new information or impair her ability to recall previously learned information or past events.
See what I mean? This type of rule-out could go on forever (and it did!).
Quirky and offbeat is how you've described Marnie, and I could picture that. Rather than thinking she has some sort of mental problem, couldn't she just be different? I tried really hard to find some diagnosis that might fit, and came up short every time. But since my field is mental health, that's not to say she might not have some other neurological disorder or something like that to account for the symptoms you've given her. You might want to check with a medical doctor to pick their brain.
I could see this a bit better if she weren't in supported living at all, but in a college dorm or something. The supported living/group home part of what you've written doesn't gel at all with her functioning level. So she doesn't take the time to understand other peoples' perspectives and she might not correctly get cause-and-effect all the time, but this wouldn't warrant the type of situation you have her living in. Her family could consider her unreliable or quirky rather than incompetent. She could be gifted--which comes with its own challenges--rather than in special education. I just think it would fit better.
I hope that this hasn't been mentally defeating, because I think Marnie can definitely go the places you want her to go. It just means changing up her backstory a bit. After you chew on this a bit, feel free to email me (or comment below) any additional questions that might come up. Otherwise, I wish you the very best with this book!