The sample consisted of 28 individuals with current PD (i.e., PD only), 40 individuals with current MDD (i.e., MDD only), 58 individuals with current PD and current MDD (i.e., comorbids), and 65 controls (
N = 191). All diagnoses were made via the Structured Clinical Interview for
DSM–IV (SCID; First, Spitzer, Gibbon, & Williams, 1996 ). SCIDs were conducted by the first author and advanced clinical psychology doctoral students. Diagnosticians were trained to criterion by viewing the SCID-101 training videos (Biometrics Research Department, New York, NY), observing two or three joint SCID interviews with the first author, and completing three SCID interviews (observed by the first author or an advanced interviewer) in which diagnoses were in agreement with the observer. Twenty SCIDs were audio recorded and scored by a second rater blind to original diagnoses to determine reliability of diagnoses. Interrater reliability indicated perfect agreement for PD and MDD diagnoses (kappas = 1.00).
Both depressed groups were required to have an age of onset of first affective disorder (dysthymia or MDD) before 18 years as Shankman et al. (2007) (
link) found that it was only those with an early onset depression who exhibited an abnormal frontal EEG asymmetry during the slot task. Participants in the MDD-only group were required to have no current or past history of an anxiety disorder (PD, social phobia, etc.). Participants in the PD-only and comorbid groups were allowed to meet criteria for additional current and past anxiety disorders. PD-only participants also met criteria for social phobia (
n = 2), specific phobia (
n = 6), PTSD (
n = 3), GAD (
n = 7), and obsessive– compulsive disorder (
n = 1). Comorbid participants also met criteria for social phobia (
n = 20), specific phobia (
n = 11), PTSD (
n = 18), GAD (
n = 1), and obsessive– compulsive disorder (
n = 9). Comorbid (63.8%) and PD-only (46.4%) participants did not differ in the rate of other lifetime anxiety disorders, χ
2(1,
N = 86) = 2.34,
ns. Control participants were not allowed to have a lifetime diagnosis of Axis I psychopathology, with the exception of a past diagnosis of alcohol or cannabis abuse (but not dependence and not current;
n = 4). Control participants were also required to have scores of less than 8 on both the 24-item Hamilton Rating Scale for Depression (HRSD; Hamilton, 1960 (
link)) and Beck Anxiety Inventory (BAI; Beck, Epstein, Brown, & Steer, 1988 (
link)).
Participants were excluded from the study if they had a lifetime diagnosis of a psychotic disorder, bipolar disorder, or dementia; were unable to read or write English; had a history of head trauma with loss of consciousness; or were left-handed (as confirmed by the Edinburgh Handedness Inventory; range of laterality quotient: +20 to +100; Oldfield, 1971 (
link)). Participants were recruited from the community (via fliers, Internet postings, etc.) and area mental health clinics. All procedures were approved by University of Illinois–Chicago Institutional Review Board.
Shankman S.A., Nelson B.D., Sarapas C., Robison-Andrew E.J., Campbell M.L., Altman S.E., McGowan S.K., Katz A.C, & Gorka S.M. (2012). A Psychophysiological Investigation of Threat and Reward Sensitivity in Individuals With Panic Disorder and/or Major Depressive Disorder. Journal of abnormal psychology, 122(2), 322-338.