(AP) - Jared Lee Loughner pleaded guilty Tuesday to going on a shooting rampage at a political gathering, killing six people and wounding his intended target, then-Congresswoman Gabriele Giffords, and 12 others. Loughner's plea spares him the death penalty and came soon after a federal judge found that months of forcibly medicating him to treat his schizophrenia had made the 23-year-old college dropout competent to understand the gravity of the charges and assist in his defense. Under the plea, he will be sentenced to life in federal prison without the possibility of parole. The outcome was welcomed by some victims, including Giffords herself, as a way to avoid a lengthy, possibly traumatic trial and years of legal wrangling over a death sentence. "The pain and loss caused by the events of Jan. 8, 2011, are incalculable," Giffords said in a joint statement with her husband, Mark Kelly. "Avoiding a trial will allow us - and we hope the whole Southern Arizona community - to continue with our recovery." Experts had concluded that Loughner suffers from schizophrenia, and officials at a federal prison have forcibly medicated him with psychotropic drugs for more than a year. Court-appointed pyschologist Christina Pietz testified for an hour about how she believes Loughner became competent. Loughner listened calmly without expression. His arms were crossed over his stomach, lurched slightly forward and looking straight at Pietz. At one point, he smiled and nodded when psychologist mentioned he had a special bond with one of the prison guards.