1. The Additive Effects of Social Anxiety Disorder on Type of Learning In a
Sample of Veterans with Unipolar Depression
1Khan, A. J., 1Kind, S., 1Milligan, C., 2, 3,4 Kamholz, B. W., 2, 5Sloan, D. M., 1Liverant, G. I.
1Psychology Department, Suffolk University, Boston, MA, USA , 2Department of Psychiatry, Boston University School of Medicine, Boston, MA USA
3VA Boston Healthcare System, Boston, MA, USA, 4Department of Psychology, Boston University, Boston, MA USA
5National Center for PTSD - Behavioral Science Division, Boston, MA USA
Social anxiety disorder (SAD) and major depressive disorder (MDD) are highly comorbid conditions with
significant negative effects on quality of life (Dalrymple & Zimmerman, 2007). Recent research has
suggested differential patterns of reward and punishment learning across these two psychiatric disorders.
Prior studies show individuals with depression exhibit decreased reward responsivity with mixed findings
regarding responsivity to punishment (Eshel & Roiser, 2010; Henriques et al., 1994). In contrast,
individuals with SAD consistently show increased sensitivity to social punishment, with inconsistent
findings regarding deficits in responsivity to social rewards (Hoffman & DiBartolo, 2010). This is the first
study to examine the differential contribution of MDD and co-occurring SAD to learning in response to
receipt of non-social rewards and punishment.
• Sample: 80 veterans recruited from a large VA Healthcare System in the Northeastern United States.
• Demographics: 87.5% male; Average age of 51.2 years (SD = 11.19); 78.8% Caucasian; 65% reported
taking anti-depressant at time of study.
• Two previously validated signal detection tasks designed to assess modulation of behavior in response
to rewards (Pizzagalli et al., 2005) and punishment (Santesso et al., 2008) were used.
• Tasks: Two blocks of 100 trials. Identify which stimuli was presented via pressing a button. Participants
were not informed that an asymmetrical reinforce ratio (3:1 rich/lean) was used for receipt of reward
and punishment feedback.
• Response Bias (RB) = preference for the less frequently punished or more frequently rewarded
stimulus. (i.e., an index of reward/punishment responsiveness). RB is calculated as:
log b = ½ log [(Richcorrect * Leanincorrect) / (Richincorrect * Leancorrect)]
• Two separate mixed model repeated measures ANOVAs: 2 (SAD status) x 2 (Block: 1, 2) controlling
for smoker status were conducted to examine RB.
Results suggest increased punishment-based learning among individuals with MDD and SAD
versus MDD alone. This is particularly noteworthy given this pattern of results did not emerge with
reward learning. This is the first study to show an influence of this co-occurring diagnosis on
punishment responsivity among depressed individuals. Although future research is needed to better
explicate the nature of alterations in punishment-based learning among individuals with SAD and
MDD, results may suggest an important treatment target in this comorbid group. Specifically,
findings may suggest the use of therapeutic strategies to decrease avoidance of punishment-related
feedback and promote continued adaptive responding despite the receipt of punishment in this
group.
A. Reward Task
• No significant between group differences in response bias (F(1,54) = .087, p = n.s.).
• Tests of within subjects revealed a significant main effect of Block, (F(1,54) = 8.05, p = .006),
with greater RB in Block 2 (M = .196, SD = .030) than Block 1 (M = .123, SD = .022).
• No significant interaction effect of Block*Group (F(1, 54) = .338, p = n.s.).
B. Punishment Task
• Significant main effect of group (F(1, 40) = 7.70, p = .008). SAD+MDD was significantly
greater in RB (M = .105, SD = .046) across both Blocks compared with MDD only (M = -.053,
SD = .034).
• Tests of within subjects revealed a significant main effect of Block (F(1, 40) = 5.07, p = .030),
with greater RB in Block 2 (M = .062, SD = .036) than Block 1 (M = -.009, SD = .028).
• No significant interaction effect of Block*Group (p = n.s.).
References available upon request. For further questions contact: akhan@suffolk.edu
A B