In Florida we have the Baker Act, which is common knowledge in FL outside even mental healthcare circles, and is a 72 hour involuntary institutionalization for examination.
Right, but that's only for attempted suicide and it doesn't mean they aren't kept AFTER. I was looking for a citation that suggests involuntary stays are shorter than a month on average, saying that there is a minimum of 3 days in some cases doesn't give me an answer to that.
Here you go:
https://www.cdc.gov/nchs/data/nhds/2average/2010ave2_firstli...; Number and rate of discharges by first-listed diagnostic categories [PDF - 58 KB]</a>