The number of critical incidents involving patients who suffer from mental health and/or substance abuse issues has decreased nearly 30 percent since 2006, according to Prince William County statistics.

There were 108 critical incidents — defined as death, serious injury, serious illness, or loss of consciousness requiring medical attention by the Virginia Department of Mental Health, Mental Retardation and Substance Abuse Services — in fiscal 2006. That number dropped to 93 the following year and to 77 in fiscal 2008, which ended June 30, according to a recent report by the county’s Office of Consumer and Family Affairs.