About half of women who smoke during pregnancy have a mental-health disorder such as depression or panic disorder, according to a new study.

Reuters reported April 11 that researcher Renee Goodwin and colleagues at Columbia University interviewed 1,516 women and found that 22 percent smoked while pregnant, and 12 percent were classified as nicotine dependent. Of the smokers, 45 percent had a mental-health disorder; the percentage rose to 57 percent among those who were nicotine-dependent.

"Health professionals with pregnant patients who smoke, but can't seem to quit, need to know that depression and anxiety might actually be the bigger problem standing in the way of their patients' efforts to quit," Goodwin said. "And for them, some form of mental health treatment, such as behavioral or supportive therapy, in addition to a smoking cessation plan may be a much more effective treatment plan than a simple nicotine patch."

The study was published in the April 2007 issue of the journal Obstetrics and Gynecology.