April 22, 2001

New Studies Examine Influences on Adolescent Depression: Mother's Depression and Smoking Can Worsen Symptoms and Impair Social Functioning

WASHINGTON - Two factors relatively common in adolescence, smoking cigarettes and having a mother who suffers from depression, both increase the adolescent's own susceptibility to depression, according to two new studies in this month's Journal of Consulting and Clinical Psychology, published by the American Psychological Association (APA).

In the first study, 110 15 year olds who experience current or past depression and who have a depressed mother (65 - 24 male, 41 female) or a non-depressed mother (45 - 9 male, 36 female) were compared on their depressive symptoms, social functioning and how they viewed their interpersonal relationships. Fifteen-year old children and their mothers were selected from a population of mothers who had been studied since they were pregnant, including several times after the birth of the child. The study sample included women who had been depressed one or more times during the child's life or had never been depressed.

At age 15, those adolescents who had been raised by a mother who suffered from depression since giving birth were more likely to have fewer friends and be less involved in social activities than their depressed peers whose mother did not suffer from depression, said lead author Constance Hammen, Ph.D., of the University of California in Los Angeles and co-author Patricia A. Brennan, Ph.D., of Emory University.

"The main difference we found," said the authors," is that the adolescents with depressed mothers had more interpersonal difficulties, probably because of the influence of their mother's depression and her own problems with social functioning. The differences were specific to interpersonal functioning and did not include academic performance."

Those depressed adolescents with depressed mothers were also more likely to have negative views of their social lives and attitudes, according to the study. But these adolescents were no more depressed nor more likely to have suffered their first episode of depression earlier or have more depressive episodes than the depressed adolescents with non-depressed mothers. And, interestingly, proportionately more boys whose mothers were depressed suffered from depression than girls whose mothers were depressed, said the authors, and more girls were depressed in families whose mothers were not depressed than boys in the same environment.

To halt the possibility of intergenerational transmission of depression, said Dr. Hammen, interventions need to include social skills building and should be targeted to children of depressed mothers to help reduce the risk of developing depression in these children.

In the second study, psychologist Michael Windle, Ph.D., and Rebecca C. Windle, M.S.W., of the University of Alabama at Birmingham investigated the interrelationship of depression and cigarette smoking in 1,218 adolescents whose average age was 15.

Those adolescents who smoked a lot (20 or more cigarettes every day for six months) were likely to have more depressive symptoms for the year and half they were followed than the adolescents who reported smoking less and lower levels of depression. Plus, the teenagers with high levels of depression (measured by questions that asked how often they felt lonely, or like a failure or hopeless) were also smoking heavily. Both smoking and depression appeared to reciprocally influence each other, said the authors, even after controlling for baseline smoking levels, alcohol and other substance abuse and delinquent activities (skipping school, aggressive toward teacher or parent, stole or vandalized personal property and/or physically hurt someone).

It could be that adolescents or adults for that matter with high levels of depression significantly increase cigarette smoking in attempt to alleviate their depressive symptoms, say the authors. "But this actually can inhibit the re-uptake of dopamine, one of the neurotransmitters implicated in causing depression when low levels exist in the brain. This can account for the underlying reciprocal relationship between nicotine and negative mood. Furthermore, those who smoke heavily for a number of months may increase their vulnerability to depression because of alterations in brain chemistry."

To help teenagers either kick their nicotine habit or keep them from smoking at all and lower their risk for depression, said the authors, smoking interventions should include programs that look at how these teenagers internalize their problems - do they have excessive negative moods, low self-esteem and suicidal thoughts? These could be reasons for starting to smoke. Arming these at risk teenagers with coping strategies could make all the difference.

Article: "Depressed Adolescents of Depressed and Nondepressed Mothers: Tests of an Interpersonal Impairment Hypothesis," Constance Hammen, Ph.D., University of California, Los Angeles and Patricia A. Brennan, Ph.D., Emory University; Journal of Consulting and Clinical Psychology, Vol. 69, No. 2.

Constance Hammen, Ph.D., can be reached by telephone at (310) 825-6085

Article: "Depressive Symptoms and Cigarette Smoking Among Middle Adolescents: Prospective Associations, and Intrapersonal and Interpersonal Influences," Michael Windle, Ph.D., and Rebecca C. Windle, Ph.D., University of Alabama at Birmingham; Journal of Consulting and Clinical Psychology, Vol. 69, No. 2

Michael Windle, Ph.D., can be reached by telephone at (205) 975-9463

The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 155,000 researchers, educators, clinicians, consultants and students. Through its divisions in 53 subfields of psychology and affiliations with 59 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting human welfare.