Dr. Lorna is an irritating talk show host and Riff's mother. She's first introduced when Zoë gets an internship working for her , at this time Riff pretends never to have heard of her. She later reveals herself to be Riff's mom when they run into each other at Zoë's house . Despite having presumably made several enemies due to her spurious comments, she is still a successful and respected psychiatrist. Like Riff, we never see her eyes.
Though a skilled and knowledgeable psychiatrist, Dr. Lorna is, as noted by Torg, moraly egotistical and always criticize her guests before they get a chance to explain their entire situation (for exemple, she accused one of her guests to be a pedophile when he confess to have feelings for a 14 years old girl, in spite of the fact that he was a 12 years old boy). She is aware, however, that her opinions over her guests are incomplete and slanderous,so, in order to avoid being scolded and dismissed by her listeners, she refuses to let any of her guests call her a second time and expose her lies, thus allowing her to defame anyone that she wants without being punished for that. Another evidence of her arrogance and selfishness is that she, according to Zoë, electrocutes anyone who successful beats her in argument in order to avoid humiliation.
A humiliating event for Lorna was when a listener called in and wanted to come clean about cheating on his wife, exposing that he had an affair with Dr. Lorna, and thus that Lorna had been involved with a married man.
Her relationship with Riff worsened over time and it's later revelated that, rather than grieving over his presumed death, Lorna openly critized his "stupidity", and even goes as far as to even promote another book at his funeral. 
Dr. Lorna is a parody of radio show host Laura Schlessinger.