Original ArticlePattern Classification of Sad Facial Processing: Toward the Development of Neurobiological Markers in Depression
Section snippets
Subjects
Nineteen participants (13 women; age range: 29–58 years) meeting DSM-IV criteria for major depressive disorder (1) according to the Structured Clinical Interview for DSM-IV Axis I Disorders (22) and clinical interview with a psychiatrist were recruited through local newspaper advertisements. Inclusion criteria were an acute episode of major depressive disorder of the unipolar subtype and a score of at least 18 on the 17-item Hamilton Rating Scale for Depression (HRSD) (23). Exclusion criteria
Group Classification of Diagnosis
From the whole brain analysis, training with the individual scans for each affective intensity, at the highest intensity, 74% of the patients were correctly classified as belonging to the patient group and 63% of healthy comparison subjects were correctly assigned to the control group. The accuracy was 68% with a sensitivity of 74% and a specificity of 63% (Figure 1, Table 2). The probability of reaching such a level of accuracy by allocating subjects at random to either group is p = .017.
Discussion
The whole brain pattern of neural activity to implicit processing of sad facial expressions significantly distinguished individuals in an acute episode of depression from healthy individuals. Moreover, the prediction of those patients who achieved a full clinical remission following antidepressant therapy from those who had persistent symptoms reached a trend toward significance. The development of neurobiological diagnostic markers for depression and predictors of treatment response requires
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