There is a scene in Asylum, a movie from 2005, that struck me in so many ways that I hit the rewind button perhaps hundreds of times over the years (perhaps indicative of my own issues upstairs) -

Stella has either lost the plot completely, or achieved enlightenment. I sway to the latter. The release of all attachment. So much so that she watches her son drown with a chilling detachment that some might call indifference, until she's snapped out of her fatal reverie. The scene mesmerised me.

Here's the movie Asylum (2005)

Mother and son are at the river around the 1.10.30 mark.