Jodi Arias, who has spent an unprecedented 18 days on the witness stand, suffers from post-traumatic stress disorder after killing her ex-boyfriend, and therefore can't remember many of her actions, according to a psychologist.

Arias, 32, has admitted to killing ex-boyfriend Travis Alexander in June of 2008 and lying for nearly two years about it, but insists she killed him in self-defense. Arias has said in a Phoenix court that she has "no memory of stabbing him and that "June 4 is an anomaly for me."

The jury today will continue hearing from Dr. Richard Samuels, a psychologist hired by the defense, who says that even though Arias admits she shot and repeatedly stabbed Mormon businessman Alexander, she can't remember the crime.

 

READ MORE FROM ABC NEWS