By John McDevitt

PHILADELPHIA (CBS) — The mother of the woman who was shot to death by police after a chase yesterday in Washington, DC (see related story) says her daughter suffered from postpartum depression after giving birth last year.

READ MORE: Philadelphia Weather: Frigid Friday Morning With Bitter Cold Air Blanketing The Region

One area expert on postpartum depression says it is a mental illness with a broad range of manifestations.

According to experts, nearly ten percent of women will suffer anxiety, sadness, and worry that something will happen to the baby or to themselves.

Then there is the most extreme form of the illness, called postpartum psychosis.

READ MORE: Letter Threatening African Americans Found At Family Dollar In Powelton Section, Police Say

“That affects about one in a thousand women — it is very rare,” says Dr. Lindsay Sortor, a clinical psychologist at the Penn Center for Women’s Behavioral Wellness. “Postpartum psychosis  is characterized by erratic  behavior, frenetic energy, illusions, paranoia, thoughts of harming the baby.”

Sortor says all forms of postpartum mental illness are treatable with medications but an accurate diagnosis must be made.

“And ufortunately, if it is not treated accurately or effectively, then it can simply persist,” she notes.

MORE NEWS: Viral Photo Appears To Show North Penn School District Teacher Taping Mask To Student's Face