Nick Stahl Placed on 5150 Taken to Hospital

6/18/2013 12:21 PM PDT

Nick Stahl -- Placed on 5150, Taken to Hospital

Sad news for "Terminator 3" star Nick Stahl -- TMZ has learned, the actor was placed on a 5150 psychiatric hold last night after being taken to an L.A. hospital.

Sources tell us, Stahl -- who has long struggled with drugs, alcohol, and other personal issues -- was transported to the medical facility around 3:30 AM this morning by a friend ... it's unclear why.

Details about circumstances of the psychiatric hold are also unclear.

It's a huge bummer ... we spoke to Stahl just last month, and he told us he was finally focused on turning his life around.