Ryan married Tricia, much to the disapproval of her father, Keith. Tricia became increasingly jealous of the attention Ryan lavished on Nina's son Phillip (Nicholas Pappone), who he thought of as his own son. When in private, the child was hostile to Tricia, believing her to have destroyed his family. Tricia pretended to be nice to Phillip for Ryan's benefit, but confided in her sister Megan (Ashley Jones) that she didn't like him. In desperation, Tricia stopped taking her birth control pills (unbeknown to Ryan) and conceived. While Ryan was furious at first, he warmed to the idea of having a child. When Tricia miscarried, she believed it was her punishment for deceiving her husband in the first place.
Tricia became obsessed with destroying Megan's relationship with Tony Viscardi (Jay Bontatibus), of whom Tricia and her father Keith disapproved. When she ran Tony down in Megan's driveway, it was suspected that Tricia had gone over the edge and intentionally killed him (whether this was true or not was never revealed). Megan disowned her sister and left town. Tricia left Ryan and moved to London with Keith.
Tricia returned six months later and asked Ryan to take her back, but he turned her down, and Victoria (Heather Tom) was still interested in him. Tricia then turned to Carter Mills (Rick Hearst) (who was actually rapist Matt Clark, having had major reconstructive surgery). Matt drugged and slept with Tricia, before convincing him to frame Nicholas Newman (Joshua Morrow), who had had Matt convicted years ago. Upon discovering that Matt had Rohypnol in his possession, Tricia realized that Matt had raped her the first time they had had sex and attempted suicide, but was foiled by Ryan. Tricia stopped Matt from raping Nicholas' wife, Sharon (Sharon Case), by driving off a cliff, hoping to kill them both. Matt died, but Tricia survived.
Ryan and Victoria resumed their relationship. Suspicious of Tricia, Victor Newman (Eric Braeden) arranged for her to move in with him in order to keep her away from his daughter. Victor not realizing that Tricia had was conspiring with the "ghost" of Matt Clark -- the "ghost" was nothing more than a psychotic delusion -- were plotting against him. One night she slipped a sleeping sedative into Victor's drink. Tricia then led Victor up to his room and laid him on the bed. Victor then realized something was wrong when Tricia disrobed and had sex with him. The next day Tricia had beaten herself to make it seem like Victor had raped her. Victor was arrested and placed in jail. Once in jail Victor had to fight for his life, but during his court hearing he escaped to save Victoria. On Ryan and Victoria's wedding day, Tricia barged into the church wearing a gown identical to Victoria's, locked Victoria in a closet and took her place at the altar, holding a gun to Ryan. Victor freed Victoria and had convinced Tricia to leave the wedding, but Victoria entered the room and Tricia shot at her. Ryan jumped in front of Victoria, taking the bullet for her. He was rushed to hospital, but died shortly after, with Victoria at his bedside. Tricia was then locked away in a psychiatric ward. In her mental state she waved goodbye to the evil Matt Clark who helped persuade Tricia to perform those diabolical plots.