The most obvious comparison to come to mind would be 'Memento' and, as far as I'm concerned, 'Before I Go to Sleep' doesn't even come close to that. However, by itself, this film provides a diverting enough mystery thriller, with the cast playing it as they need to. And, at around 90 minutes, the film doesn't over-stretch its set-up.
It, perhaps, isn't the most inventive film, as it is filmed a paced in a somewhat generic mystery-thriller fashion and reuses various elements frequently found in the genre. It's also a film that lacks any real thrills when it gets down to it (probably because of the lack of much emotional depth earlier in the film). As a whole, though, it did do the job of distracting me for 90 minutes.