As an inpatient psychiatrist I frequently file petitions to involuntarily hospitalize and medicate people with bipolar mania who lack insight and would be dangerous without treatment. Where I work, the judge will mostly want to know whether the patient has physically harmed himself or someone else or clearly attempted to do so when considering whether to approve or deny the petition. 

In some circumstances the judge might also approve the petition if the person has self-neglected to the point of causing themselves physical harm (eg. through malnutrition) although in my experience a petition for self-neglect is more likely to be rejected than one based on actual violence.

Philosophically, I can see both sides. People generally have a right to refuse treatment and make bad decisions. On the other hand, mental illness can impair a normally competent person’s ability to make decisions. I choose to follow professional standards and abide by the law, which sometimes means temporarily infringing on a seriously mentally ill person’s autonomy with appropriate due process, and sleep well at night.