Hormone Effects

Findings from studies that focus on pubertal hormones and adjustment reveal that effects vary across study, by gender, by hormone, and by outcome. In research focused on hormone-behavior links in girls only, findings indicate that increases in estradiol, specifically during the most rapid period of increase during puberty, have been associated with negative affect (Brooks-Gunn & Warren, 1989; Warren & Brooks-Gunn, 1989). Estradiol levels increase dramatically during puberty, and they correlate strongly with many of the other hormone levels. In the first set of analyses, ordinary least-squares regressions (OLS) were performed in order to compare findings with those of other researchers. Age and five hormones, FSH, LH, estradiol, testosterone, and DHEAS, were entered as possible predictors. None of the individual variables had significant beta weights in the linear analysis.

The second set of analyses tested both linear and nonlinear effects (the square of each hormone was entered in order to test for nonlinear associations). Findings indicated a nonlinear effect of estradiol for depressive affect and a negative linear effect of DHEAS for aggressive affect. Based on the significant nonlinear estradiol finding, girls were categorized into 4 hormonal stages based on the range of their estradiol levels; each range affects reproductive organs and functioning of the reproductive system differently. Stage I girls were considered prepubertal, stage II girls were experiencing beginning pubertal development, stage III girls were considered to be in mid- or late- puberty, and stage IV girls were experiencing cyclic menstrual function. Estradiol levels were 0-25, 26-50, 51-74, and greater than 75 pg/mL, respectively, for each stage.

As seen in Figure 16.4, results indicated a significant quadratic effect for girls' depressive affect while controlling for age, with highest levels of depressive affect in the groups (stages II and III) that demonstrated initial increases in estradiol (Brooks-Gunn & Warren, 1989; Warren & Brooks-Gunn, 1989). In follow-up analysis, this hormone-affect association was found to persist over the course of one year (Paikoff, Brooks-Gunn, & Warren, 1991). The curvilinear nature of the hormone-affect association fits the premise that activational effects may be greatest when the endocrine system is being turned on. However, the magnitude of the hormone effect was small, accounting for only 4% of the variance in negative affect. Other studies have also indicated that when hormone-affect associations are found, they generally account for a small portion of variance in behavior (e.g., Buchanan et al., 1992). Social factors, as measured in this study by positive and negative life events, accounted for more variance than hormonal pubertal factors alone (8%-18%), as did the interaction between negative life events and pubertal factors (9%-15%). Thus, hormone effects on affect may be overshadowed by environmental events.

Angold and colleagues have conducted a number of studies on links between pubertal factors and depression. The first study assessed age, pubertal timing, and Tanner stage on the probability of depression in both boys and girls over four waves of data collection from the Great Smoky Mountains Study (Angold, Costello, & Worthman, 1998). Depression included three diagnoses: DSM-IV major depressive episode, dysthymia, and minor depressive disorder. Findings revealed that only after the transition to mid-puberty (Tanner Stage III and above) were girls more likely than boys to be depressed. Timing of the pubertal transition did not affect depression, whether measured by onset of menarche or Tanner stage development. These findings imply that some aspect of puberty itself was related to depression, rather than the age at which the pubertal level was achieved. Further analyses considered HPG axis hormonal effects on depression in girls, in order to disentangle the effects of the morphological changes of puberty and the hormonal changes underlying them (Angold, Costello, Erkanli, & Worthman, 1999). Results indicated that the effects of testosterone and estrogen in the model eliminated the apparent effect of Tanner stage. The Odds Ratio associated with Tanner stage was reduced from 2.9 to 1.0 by the addition of these hormones, meaning that before the hormones were added to the model, the likelihood of depression for girls at Tanner stage III and above was nearly three times as great as the likelihood of depression for girls below Tanner stage III. An Odds Ratio of "1" indicates that there is no difference in the likelihood of depression based on Tanner stage grouping). In order to examine the possibility that hormone thresholds may be present, the researchers divided the ranges of testosterone and estrogen into quintiles and plotted rates of depression for each quintile. The effect of testosterone was particularly marked and was manifested only above a certain threshold, above the 60th percentile of testosterone levels in this sample (corresponding to a

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