We conducted all tests using a two-tailed p value of .05. Before examining the primary hypotheses, we conducted analyses to identify potential confounds. Then, we conducted bivariate correlations of life event and symptom variables. To examine hypotheses, we conducted partial correlations of level of goal-attainment life events with follow-up symptoms, controlling for baseline symptom levels. We conducted separate analyses for depression (MHRSD) and mania (BRMS) and for goal attainment and positivity.
To determine whether goal-attainment life events were confounded with demographic or illness characteristics, we computed Pearson product–moment correlations. No significant correlations emerged between degree of goal attainment and age, gender, years of education, Hollingshead (1957)
occupational status, onset age, number of hospitalizations, number of episodes, number of depressions, or adequacy of medication levels.
Means and standard deviations of all dependent variables are presented in . Relatively few individuals were experiencing clinical levels of symptoms at the time of the baseline symptom assessment; approximately 10% were experiencing a major depressive episode (MHRSD > 17) and 7% were experiencing a full manic episode (BRMS > 16). For the overall sample means, neither depression nor mania changed significantly from baseline to follow-up: for mania, dependent t(42) = .45, ns; for HRSD, t(42) = .07, ns. Baseline symptoms were not correlated with follow-up symptoms for mania (r = .07, ns, N = 43) but were moderately correlated for depression (r = .56, two-tailed p ≤ .0005, N = 43).
Means and Standard Deviations of Mania and Depression at Baseline and Follow-Up
Next, we examined bivariate correlations between goal attainment and symptom severity scores. Goal attainment was not significantly related to baseline manic (r = .13, p = .40, N = 43) or depressive symptoms (r = −.17, p = .28, N = 43). These results suggested that the severity of symptoms in the month before the life event was not an influence on the magnitude of goals achieved. Goal attainment was not significantly related to follow-up depressive symptoms (r = .02, p = .86, N = 43). As predicted, goal attainment was significantly related to higher levels of follow-up manic symptoms (r = −.36, p ≤ .05, N = 43).
Next, we examined the change in manic and depressive symptoms following goal attainment, using partial correlations to control for baseline symptoms. The partial correlation of goal attainment and manic symptoms, controlling for baseline manic symptoms, was significant and in the expected direction, r
(40) = −.37, p
= .01. The partial correlation of goal attainment with depressive symptoms, controlling for baseline depressive symptoms, was not significant, r
(40) = .15, p
= .36. As assessed using z
transformations to compare the difference between partial correlations (Meng, Rosenthal, & Rubin, 1992
), manic symptoms increased more than depressive symptoms did after goal-attainment life events (z
= 2.02, p
As a point of comparison, we examined whether positive events predicted changes in manic and depressive follow-up symptoms. As above, we first checked whether symptoms changed from baseline to follow-up (positive events involved different symptom assessments). Matched t tests revealed that neither manic nor depressive symptoms changed from before to after the event period. Bivariate correlations revealed no relation between positive events and baseline manic (r = .10, ns, N = 43) or depressive symptoms (r = −.16, ns, N = 43) nor between positive events and follow-up manic (r = −.003, ns, N = 43) or depressive symptoms (r = −.07, ns, N = 43). The partial correlations, controlling for baseline symptoms, also revealed no relation between positive events and manic follow-up symptoms, r(40) = −.02, ns, or depressive follow-up symptoms, r(40) = −.02, ns. Goal-attainment life events were more related to manic symptoms than positive events were (z = −1.95, p < .05).