When Alex is shown in the bathtub after slitting her wrists, the cuts are vertical, but in the following scene at the therapist's office the scars are horizontal.
When John Lowe imbibes the sleeping pills, before taking a sip of water to wash them down (whole,) there is the loud, crunching sound of the actor Wes Bentley chewing the props. Which, are probably sugar pills he is crunching... Afterwards, both characters on-screen are withholding smiling at this error for several seconds afterwards, as the camera rolls on through.