Watch CBSN Live

Questions surrounding Capitol Hill shooting include postpartum depression

Postpartum depression can lead women to have harmful thoughts about their babies, but could it cause a mom to engage in erratic behavior?

That's what many are asking following the death of Miriam Carey, the 34-year-old dental hygienist who was shot and killed by police Thursday after she ran her car into a barricade near the White House and led officers on a high-speed chase through the Washington D.C. streets towards the Capitol building.

Raw video: Capitol Hill car chase, shooting

Carey was driving with her 1-year-old daughter in the backseat. She reportedly had "emotional issues," CBS News correspondent John Miller said.

Her mother, Idella Carey, told ABC News her daughter suffered from postpartum depression following the birth of her baby in August 2012.

"A few months later, she got sick. She was depressed.... She was hospitalized," Idella Carey said.

It's not clear the exact nature of the mental health condition, and investigations remain ongoing.

Postpartum depression affects up to 10 to 15 percent of motherswithin the first year of giving birth, according to federal estimates.

Up to 85 percent of women who give birth may feel some depressive symptoms shortly after. These "baby blues" include crying, mood swings, sadness, anxiety, trouble sleeping and feelings of being overwhelmed. Those symptoms typically go away in a week or two without treatment, Dr. Kristen Leight Wesley, a professor of clinical psychiatry in The Women's Program at Columbia Psychiatry, explained to

Symptoms of postpartum depression, on the other hand, can last much longer and be more severe. It can occur any time within a year of childbirth, but typically starts about one to three weeks after delivery. If the "baby blues" don't start to fade after a week or the feelings get worse, a postpartum depression diagnosis is likely appropriate, notes the American College of Obstetricians and Gynecologists (ACOG).

Capitol car chase: New details on driver's mental state

Risk factors for postpartum depression include history of depression, having depression and anxiety during the pregnancy, not having enough social or partner support, difficulties or complications during labor, and low socioeconomic status.

Affected moms may feel worthless and have trouble completing their daily tasks, which may include taking care of the baby or even themselves. Intense concerns or worries about the baby may occur or women may lack interest entirely in the baby. Many develop intrusive fears of harming the baby which can be extremely distressing, but ACOG notes these feelings are almost never acted on by women with postpartum depression. The thoughts themselves, however, may trigger guilt, which worsens their depression.

"There are so many women (with postpartum depression) that suffer in silence that never have a thought of hurting themselves or their child," notes Wesley, who was not involved in the Washington D.C. case. "But in extreme situations where they lose touch with reality, that can lead to a situation."

In rare cases, women may develop a more serious condition called postpartum psychosis in which they experience hallucinations or delusions. They may actively try to harm themselves or the baby. Women may be more at risk for this if they previously had been diagnosed with bipolar disorder or have traits of the condition, according to Wesley. Having family members with bipolar disorder and schizophrenia may raise risk for postpartum psychosis, ACOG adds.

Women showing signs of postpartum psychosis are in the midst of a psychiatric emergency, says Wesley, and should be taken to the emergency room immediately for evaluation. Women with postpartum psychosis experience "waxing and waning" fluctuations in their symptoms, so family reports of symptoms are crucial for a doctor's diagnosis.

"What is worrisome about that, is women who present for evaluation when they are lucid -- they are deemed okay and discharged," said Wesley.

Women with delusions might believe they are being controlled by an outside force and believe harming themselves or the baby is what they need to do, for example.

CBS News' John Miller reported that Carey fell down some stairs and injured her head in April 2012. That hospital visit is when she found out when she was pregnant, he added. Carey was given a disabled parking permit shortly after. But doctors from the medical suite where she worked complained that she was tying up parking in front of the building, and asked her to move her car back, which reportedly led to a dispute that resulted in her termination.

From then on, she appeared to be suffering from emotional issues which eventually got the attention of Stamford police in Dec. 2012.

CBS News' Bob Orr reported that law enforcement officials said Carey told Stamford police at that time that she was a prophet. She also reportedly believed that President Obama was going to "lock down" Stamford and that he had her and her residence under electronic surveillance.

Because of her behavior, Carey was taken for a mental-health evaluation. She was not arrested or charged with a crime at the time, and it was unclear what kind of treatment was prescribed after her evaluation.

The cause of postpartum depression or psychosis is not fully understood, but is thought to be related to several factors including changing levels of the female sex hormones estrogen and progesterone, which drop sharply after birth (and lead to the baby blues); other physical stresses in the body from giving birth; and social stress. Raising a newborn can be stressful enough, but Wesley points out many of these women feel socially isolated during the transition to motherhood.

Women whose baby blues don't resolve within a week should contact their doctor, who may refer them to a specialist. They may get treated with therapy or group sessions where they can meet other new moms, or they might be given antidepressants. Support from family and partners could be especially important to get through postpartum depression, Wesley added.

She emphasized that you shouldn't wait to get help if the symptoms are intense from the outset. With the baby blues, women can still enjoy happy moments of being a mother despite their mood and anxiety fluctuations. But with postpartum depression or psychosis, signs could be present from the start.

It's crucial to get help as soon as possible because this poor response and disengagement to a baby caused by postpartum depression can lead to long-lasting consequences for the mother-child bond, says Wesley.

Postpartum Support International has more on resources to get help for postpartum depression.