A former hairdresser who claims postpartum psychosis caused her to run over her baby son in 1987 described on Thursday her descent into insanity to a jury that has the power to release her from court-ordered mental supervision.

Sheryl Lynn Massip, 46, repeatedly wiped away tears as she recounted her symptoms in the weeks after giving birth to her first child, Michael. The Southern California housewife said she would find herself outside without knowing how she got there, saw the walls and ceiling of her apartment move and thought her son's eyes were changing colors.

"I thought he was possessed," said Massip, who remarried and now goes by the last name Smith. "It's like recalling a dream that I had 23½ years ago. It's like I was in a walking nightmare."

Massip was convicted of murder in 1988 for running over her 6-week-old son on her 23rd birthday, but a judge set aside the verdict and declared her not guilty by reason of insanity in a case that generated national debate about the limits of a "baby blues" legal defense.

The devout Lutheran testified during her criminal trial that she thought the child was a doll when she placed him under the left front wheel of the car and voices ordered her to put him out of his misery.

Since then, Massip has been under court-ordered medical care but hasn't served any time in prison or a state mental hospital. She has been diagnosed with bipolar disorder and a hormone imbalance that causes bouts of deep depression every month with her menstrual cycle, she said under questioning by Orange County prosecutor Aleta Bryant.

Massip cannot leave the state or move without court permission and has a home visit every three months — conditions she now feels are oppressive, her attorney Milton Grimes said outside court.

Massip has moved to Merced in Northern California with her family and is raising a healthy, happy 14-year-old daughter, Grimes said. She has appeared on several national TV talk shows, including "Oprah" and "Larry King Live," to discuss postpartum depression.

If the jury finds she is no longer a danger to herself and others, she will be declared legally sane and have no more restrictions on her life, he said. Her care providers agree she no longer needs supervision, he added.

"She wants freedom from the system that restricts her," Grimes said. "She's always going to live with the guilt of killing her son. That prison will always be there and she will always be in it."

Prosecutors, however, believe Massip could relapse dangerously if she is left to manage her own care.

Bryant claimed Massip discontinued all medication at one point in 2003, provoking so much concern that the court issued an order requiring her to comply with treatment. She also missed nine of 12 therapy appointments that year and often stops taking pills because she doesn't like the side effects, Bryant said.

She was hospitalized in 1992 and placed on suicide watch after cutting off her hair, according to testimony.

Massip told jurors Thursday she never ignored doctors' orders and never quit any medication without asking.

"I had already come to grips with the fact that I needed to be on medication for the rest of my life," Massip said. "I asked for a readjustment in my medication, but I've never gone off of them so I don't know where that's coming from."

Massip's teenage daughter, Kayla Smith, testified that her mother was a doting parent who was never violent and who was active in two churches. The teen said she kept an eye out for her mother's bipolar symptoms, such as not sleeping or eating or acting overly nervous, and told her father if she noticed anything wrong.

"She's just like any regular mom. She does things with me, helps me with my homework, drives me places," she said.

"I could talk to her about anything. She's there for a hug, and she's always caring about other people."

Massip, a petite woman, appeared in court wearing a green suit jacket and black slacks with her hair styled short. She remained calm on the stand and ended each reply with the word "ma'am."

During Massip's murder trial, she told jurors her son was crying up to 18 hours a day and vomited constantly, but she got no help from her husband and was exhausted. She said she began having nightmares about committing suicide and started hearing voices.

"They said, 'Put him out of his misery.' It was over and over," she said at trial.

Massip testified that on April 29, 1987, she lost her final toehold on sanity: She said she threw the baby in front of a passing car, but when the driver swerved, she picked up the infant and returned home.

There, she recalled striking him in the head in the garage with some type of tool until she finally put the infant face-up under her car's left front tire and drove over him.

She dumped the body in a trash can near her home and told her husband a stranger had snatched the baby, according to testimony.