PHOENIX – A psychological report released Thursday warned that while Jared Lee Loughner was competent to plead guilty in the Tucson mass shooting, he remained severely mentally ill and his mental condition could deteriorate under the stress of a trial.

The report was prepared in late April by a federal Bureau of Prisons psychologist who testified in court Tuesday before a judge allowed Loughner to plead guilty in the January 2011 mass shooting.

Psychologist Christina Pietz’s report said Loughner’s improved condition was due to medication.

But because his condition could “wax and wane, I recommend the court expeditiously address issues related to his situation,” Pietz wrote. “Mr. Loughner is currently competent to proceed. However, because of his fragile mental state, there is no guarantee he will remain competent for an extended time.”

Loughner pleaded guilty to 19 counts under a plea agreement that guarantees he will spend the rest of his life in prison. He is to be sentenced in November for the mass shooting that left six people dead and former U.S. Rep. Gabrielle Giffords and 12 others wounded.

The report covering a period from late January to late April said medication was controlling the psychotic symptoms of Loughner’s schizophrenia.