However, girls and boys experience this change differently. The study shows that girls tend to initiate the transition to a mixed-gender friendship earlier than boys, and continue the transition at a faster pace than boys. The researchers found that girls who make friends with boys early and quickly are more likely to start drinking and using drugs in later adolescence.

The researchers examined almost 400 adolescents, 48 percent of which were girls, between the ages of 12 to 18, from a French-speaking school district in Canada. The students were interviewed every year over a period of seven years about their friendships and their substance use. They found that unlike girls with male friends, boys who befriended girls in early adolescence were not more likely to develop substance abuse problems in their later teen years.

This could have something to do with the emotional support girls offer compared to boys Boys who have female friends benefit from this support, whereas girls with male friends don’t get the same amount of support from the males.

Lead author Dr. François Poulin of the University of Quebec at Montreal said that boys reported receiving higher levels of emotion support from their female friends, whereas girls receive support from their same-sex friends. He added that it’s possible that boys are less likely to engage in substance abuse because they get emotional support from their female friends.

The study also found that among girls, antisocial behavior and going through puberty early were associated to an increase in the number of male friends they had. Girls also tended to form friendships with males outside their school environment, which could be associated with substance abuse, as older teens could purchase alcohol for them. (The legal drinking age in Canada is 18.)

However, by mid-adolescence, the negative impact of other-sex friendships becomes less powerful as having both male and female friends becomes more normal, and as girls become more likely to form romantic relationships with members of the opposite sex.

The researchers say more studies are needed to examine the context of these friendships, including the settings, the entire friendship network, and the role of parental supervision. They added that future studies could also look at associations between other-sex friends and educational achievement or antisocial behavior.

In the meantime, the researchers suggest that parents take a more active role in monitoring their daughter’s friendships, especially with older boys.

Source: Science Daily, Early Male Friendship as a Precursor to Substance Abuse in Girls, March 10, 2011

Among the 1611 college students participating in the new research, both men and women reported depression after a relationship ended or got into trouble; however, men were more likely to turn to drugs and alcohol. Study author Robin Simon said that men missed the support they received from their romantic partners, but that women emphasized simply being in relationships.

"Having a relationship is something that is emphasized constantly for women," she said. "Part of our emotional culture is that men should not feel sad. While women are free to feel and express emotion, men turn to mood-altering substances to get rid of culturally inappropriate feelings."

One study conducted by Van Der Zwaluw., et al 2009, examined the associations between adolescent alcohol use and participating adolescents’ perception of their partners’ alcohol use. The primary focus of this study was determining whether friends and partners tend to become like each other in relation to alcohol use, or do people instead tend to gravitate toward similar friends or partners.

To find the answer to these questions, researchers interviewed parents and adolescents from 428 Dutch families. These interviews were conducted once a year for four years. Each family participating consisted of two parents and two siblings with a retention rate of 81 percent across the study.

Across the study, both siblings participated in the process. For younger siblings, the mean age was 13.4 years; for older siblings, the mean age was 15.2 years. Those participants who reported romantic involvement at a given time within the study were used in the analysis. This included 36 percent of the older siblings and 26 percent of the younger siblings.

Through methods of self-reporting, researchers were able to capture information on the frequency of alcohol use during the past four weeks from the point of interview; whether or not the individual was in a steady romantic relationship at the time; and their own estimation of their partner’s frequency of alcohol use over the same four week time period.

The findings from this study indicate that when evaluating a participant’s estimation of their own alcohol use, as well as the frequency of their partner’s, participants and their romantic partners appeared to have relatively similar alcohol use habits and patterns. At the same time, a partners’ alcohol use did not appear to significantly predict later participant alcohol use if prior participant alcohol use was taken into account.

By contrast, the study did reveal that adolescents tend to select partners with similar drinking habits. Based on data gathered, a participant’s use of alcohol at a given time rather accurately predicted their partner’s alcohol use one year later.

This study did present certain limitations, the most glaring was the fact that data collected was dependent upon self-reporting, both for an individual’s own and a partner’s alcohol consumption. In some cases, the adolescent may have started dating earlier than most, which could skew the results.

Researchers concluded that adolescents and their romantic partners are similar in the amount of alcohol they consume. Based on study results, researchers suggest that this similarity is the result of initial selection of a partner and not the influence of a partner’s drinking habits on another adolescent.