It is also partly because we are less inclined to lock up, beat or detain people who violate social norms in western countries anymore.

Neither do we socially support those properly, turns out running mental health and substance abuse support is difficult, politically charged, full of potential for liability, thankless and expensive.

I have older relatives who were involved in the mental health system in the 50's and 60's, it was, to put it mildly, not a particularly humane time but "it sure got crazies off the streets".

On a related note, in .jp the police can detain you for about a month without charging you.