"That would be unconstitutional if their only "crime" was drug addiction."

RCW 70.96A.140
Involuntary commitment.

(1) When a designated chemical dependency specialist receives information alleging that a person presents a likelihood of serious harm or is gravely disabled as a result of chemical dependency, the designated chemical dependency specialist, after investigation and evaluation of the specific facts alleged and of the reliability and credibility of the information, may file a petition for commitment of such person with the superior court, district court, or in another court permitted by court rule.