The Girl on the Train by Paula Hawkins (2015)
Rachel takes the train into London every day, though she has been fired from her job for being drunk and insulting and doesn't want to tell her roommate. She looks out the window and pays special attention to her old house, where her ex-husband lives with Anna and their daughter Evie. A few doors down she see what she thinks of as the perfect couple - she gives them names, but we later find out they are Megan and Scott. We hear the story through the voices of the three women - day by day. Mostly chronological, but hear the past of one, when we need to. Megan disappears and Rachel thinks she saw something that could be useful. She keeps bothering her ex-husband Tom and his wife Anna.
I did not like being in the mind of alcoholic Rachel, especially in the beginning. I drank a lot in my youth, but it was always for fun, with people, never to get away from myself or my problems. Well, maybe we did drown our sorrows once in a while, but it didn't feel like this. So I am not sure what makes it so disconcerting. Watching a Harvard professor lose her memory in Still Alice was difficult, but did not make me feel this uncomfortable. Megan was also struggling with various mental issues, and she too made me uncomfortable, though as an undergraduate psych major I used to be interested in what made people tick. I wrote the above paragraph while I was in the beginning of the book. We do get an explanation and that circumstances and life had made Rachel and Megan that way, which somehow mitigated my discomfort by the end of the book.