Results
MDD
REGRESSION
A total of 459 subjects were included in the test trial 810. Among them 58% were females and 42% males. The description of the demographic data of the MDD population is presented in Table Demographic data of the MDD population.*Days between screening and baseline visits.The means (±SD) baseline total HAMD-17total score were 23.13 (±2.89), 23.51(±3.28), and 23.81 (±3.23) for paroxetine CR 12.5 mg, paroxetine CR 25 mg, and placebo, respectively.The grid search analysis indicated that the optimal number of layers was 3 and the optimal number of nodes per layer was 12, 6, and 5, respectively. The optimality criteria was based on the best predictive performance of the model.The final neural network layout for the ANN analysis is presented in Fig. ANN Analysis. Final neural network layouts for the analysis conducted using the changes from screening to baseline of the individual items of the HAMD-17 clinical scale used as potential predictors of the response (resp = response to placebo).The size of the connecting lines in the neural network are analogous to the coefficients in a standard regression analysis. They determine the relative influence of information that is processed in the network. A null weight will be associated to variables not relevant for predictions. The overall predictive performance of the ANN model was assessed using the area under the ROC curve (AUC). The value of the AUC was 0.81, with a 95% confidence interval of 0.64–0.97. This value, statistically greater than the noninformative threshold of 0.5, represents the predictive performance of the ANN model to predict the probability to show a non-specific response to a treatment using the individual item score changes of the HAMD-17 scale assessed in two pre-randomization time points (i.e., screening and baseline).The ANN model was used to predict the individual propensity to respond to placebo in each subject included in the three arms of the study.The percentage of subjects with estimated propensity to respond to non-specific TEs in the intervals <0.2, 0.2–0.4, 0.4–0.6, 0.6–0.8, and >0.8 is presented in Fig. Propensity probability. Distribution of the propensity probability to a placebo effect by treatment.The results of the non-weighted and weighted MMRM analyses with the estimation of the effect sizes are presented in Fig. 