So, I want to apologize to the author and publisher for a delay in reviewing this book, as i did receive an advanced reader copy and wanted to leave my honest review sooner. However, on to the book- the concept of this book is "outbreak of insomnia, depression and violence in a small Tennessee town thought to be related to a virus or other pathogen". I will admit that I do not think this book is for the average reader. I wouldn't necessarily classify the book as a "thriller" as much as it is a sort of procedural. Rather than a sort of "28 Days Later" type story, it's more of the Contagion level of a slow burn. Now, this is especially true for the first half or so (for which it took me about a week to read in short sprints), but it definitely picked up during the second half and did turn a bit more into a thriller.
Things I liked: I thought Kris was really empathetic and honestly the ideal researcher for this town (maybe too ideal?). Dan was great but I really enjoyed the dorky IT guy Paul even more. It was heavy on the medical and statistical jargon at times, but I loved that aspect- that is why I watch science fiction type movies, to appreciate the way they integrate known science with hypothesized science. I also really thought the story was well developed and slowly revealed in a way that felt like I was really helping to unearth the mystery in the town. And while the town was dangerous and Kris got into some sticky situations, I didn't recall feeling like specific ones were unrealistic- like this is a small town with a dwindling police force ability and increasing vigilante activity, which almost led to the sticky situations.
I didn't always like how over-explained things were. It took until about halfway before they stopped writing out her explanation of her goals with the research, and I had already understood that by about the third interaction. At times, it felt in a weird way like propaganda for a sort of 'good sleep cures all', but then they did use real medications as well so it balanced that out.
Overall, if you want a sort of medical procedural thriller, this book could be for you. I'd give it a 3.5/5 (rounding up), because while I felt that a few moments felt slow, the story was really well planned and written. I actually need to now go back and read the first story by this author!