Studies: Smoking, Childhood Relationships Can Increase Clinical Depression

Scientists have found two new links to adult depression: smoking and childhood relationships. These two long-term studies have pinpointed direct relationships between these two causes and depression in those studied.

Depression may be described as feeling sad, blue, unhappy, miserable, or down in the dumps. Most of us feel this way at one time or another for short periods. It often runs in families. This may be from heredity, learned behavior, or both. Even with a genetic predisposition, it is usually a stressful or unhappy life event that triggers the onset of a depressive episode.

Common causes of depression include: disappointment, whether it be due to school, work, or relationships; sleeping problems, extreme or prolonged stress, death of a friend or relative, childhood events like abuse or neglect, social isolation, and nutritional deficiencies. New research has found two new possible causes of depression.

One study suggests that men who have a poor relationships with their siblings during childhood have a higher risk for depression. Dr. Robert Waldinger, director of the study of Adult Development at Brigham and Women's Hospital in Boston, authored the report of his team's findings in the American Journal of Psychiatry. The 68-year study, one of the longest studies of adult psychosocial development ever done, collected data on 229 men from the time they were
teens until they were in their 50s. The researchers looked at the men's quality of life and their relationships with their siblings, the quality of parenting they had, and any family history of depression.

The researchers are unclear as to what their findings mean. "It could be that not being close to a sibling is an early harbinger of later depression," Waldinger said. "Or it could be that being close to a sibling helps you develop you skills dealing with peers."

They are sure there is a connection, just unsure of why.

One expert, Dr. Gregory Simon, a psychiatrist and mental health researcher at the Group Health institute in Seattle, said that the study provides a valuable insight into the relationship between early life development and long-term risk for common mental health and substance use problems. He agreed with Waldinger and his colleagues that the study suggests there is a relationship between depression and childhood sibling relationships but the direction of the relationship couldn't be determined.

"It is certainly possible that poor relationships with siblings during childhood have significant and enduring negative effects on mental health," Simon said. "It is also possible, however, that poor relationships with siblings are one of the early signs of depressive illness."

Another long-term study, suggests that smoking may also be a link to depression. While research has often suggests that drugs may be a cause of depression, this study found a direct link between cigarette smoking and depression.

The study from the Department of Public Health at the University of Helsinki consisted of 4,000 male and 5,000 female finnish twins, whose health and health behavior were monitored over a 15 year period suggests that persistant chronic cigarette smoking predicts the development of depressive symptoms.

The study, published in Psychological Medicine, also found when adjusting for other factors associated with depression, the elevated risk due to persistant smoking remained significant only among men.

There was also evidence of a short term increased risk of depression among smokers who had quit. Those who quit and remained off cigarettes in the long run did not have an increased risk compared with never smokers. Dr. Tellervo Korhonen from the University of Helsinki, lead author of the study, said in a statement to Reuters Health that this may reflect a relatively long recovery process from the effects of cigarette smoking.

"When people start smoking, the immediate effects of nicotine in the brain are rewarding and pleasurable," Korhonen explained. "This suggests self-medication, where a person who has mood problems seeks relief via cigarette."

Because addiction to nicotine is as strong as an addiction to heroin, abstinence is difficult.

"Smokers who are vulnerable to depression may need specific pharmacological treatment and behavioral support to overcome the earlier phase of abstinence," Korhonen said. After that, "their chances to quit successfully improve."

In any given 1-year period, 9.5 percent of the population, or about 20.9 million American adults, suffer from a depressive illness. This is a serious and sometimes fatal disorder that needs to be treated. It is important that if you or a loved one think you might be experiencing depression that you seek treatment.