This list has been compiled for educational purposes only. It is not intended to belittle the authors/characters mentioned or any sort of disease.
Dr. No Syndrome: A terrible, debilitating syndrome that afflicts only the villains of a novel. Its symptoms include maniacal laughter, insanity, the wearing of dark colours and a general lack of realistic motivation. Dr. No Syndrome is a silent killer and may prove fatal to an author’s credibility and any suspense that has built up before the villain’s appearance. It is most prominent, but certainly not limited to, the fantasy genre.
Book Two Disease: A common, mild disease that afflicts around 90% of book series. Its many symptoms include poor writing, no character development, subplots that go nowhere and in its most severe cases, the resurrection of a favourite character from the first book. Book Two Disease is rarely fatal as a writer’s fans will usually continue reading the series to see what happens in the end. Unfortunately, it spans across all genres.
Paolinism: A rare disease that affects both old and young writers alike, but is more prevalent among the young. Its symptoms include head-hopping, too much description, a slow plot, taking years to write one book and alienating many readers by leaving and open ending. Paolinism is usually a fatal disease, but there are cases in which the fan base is so dedicated, nothing will alienate them. It is more prevalent in high fantasy, although it spans across all genres.
Marysuenza: Marysuenza is not a rare disease, but it is not nearly as widespread as Book Two Disease. Its symptoms include a perfect protagonist that can do no wrong, a cliched plot and obvious author wish fulfillment. Despite extreme reader annoyance, it is usually only fatal in new novelists. It is most prevalent in YA fiction, but it is by no means an isolated disease.
These are just a few of the common diseases found in fiction and this is by no means a comprehensive list. What other diseases have you found in fiction and what are their symptoms?