THE TIME-COURSE OF NONCHRONIC MAJOR DEPRESSIVE DISORDER - UNIFORMITY ACROSS EPISODES AND SAMPLES

Background: Most natural history studies of affective disorders have e mphasized the prediction of eventual recovery. Little is known of chan ges over time in the immediate probability of recovery. Methods: To id entify regularities in the timing of recovery from nonbipolar major de pressive disorders, we considered only episodes that began during foll ow-up to increase the accuracy with which onsets were timed and to lim it the study sample to individuals who had a demonstrably episodic cou rse. Five participating centers conducted baseline assessments and fol lowed probands (N=605) and nonclinical subjects (relatives, controls, and spouses, N=826) up for 6 years. During that time, 359 probands had at least one prospectively observed episode, and 181 had two episodes ; corresponding numbers for the nonclinical subjects were 216 and 78, respectively. Our analyses considered the distribution of episode leng ths across ascertainment source (probands vs nonclinical subjects), ce nter, and episode number (first vs second prospectively observed episo de).Results: Distribution was remarkably uniform. Regardless of ascert ainment source, center, or episode number, recovery occurred within 3 months in 40% of episodes, within 6 months in 60%, and within 1 year i n 80%; 20% had more protracted courses. Conclusions: Once triggered, t he immediate likelihood of recovery changes over time in a predictable fashion. This has practical implications for the study of antidepress ant efficacy and theoretical implications for factors involved in affe ctive dysregulation.