Diagnosis
of major depressive disorder (MDD) using resting-state
functional connectivity (rs-FC) data faces many challenges, such as
the high dimensionality, small samples, and individual difference.
To assess the clinical value of rs-FC in MDD and identify the potential
rs-FC machine learning (ML) model for the individualized diagnosis
of MDD, based on the rs-FC data, a progressive three-step ML analysis
was performed, including six different ML algorithms and two dimension
reduction methods, to investigate the classification performance of
ML model in a multicentral, large sample dataset [1021 MDD patients
and 1100 normal controls (NCs)]. Furthermore, the linear least-squares
fitted regression model was used to assess the relationships between
rs-FC features and the severity of clinical symptoms in MDD patients.
Among used ML methods, the rs-FC model constructed by the eXtreme
Gradient Boosting (XGBoost) method showed the optimal classification
performance for distinguishing MDD patients from NCs at the individual
level (accuracy = 0.728, sensitivity = 0.720, specificity = 0.739,
area under the curve = 0.831). Meanwhile, identified rs-FCs by the
XGBoost model were primarily distributed within and between the default
mode network, limbic network, and visual network. More importantly,
the 17 item individual Hamilton Depression Scale scores of MDD patients
can be accurately predicted using rs-FC features identified by the
XGBoost model (adjusted R
2 = 0.180, root
mean squared error = 0.946). The XGBoost model using rs-FCs showed
the optimal classification performance between MDD patients and HCs,
with the good generalization and neuroscientifical interpretability.