Increased salience of gains versus decreased associative learning differentiate bipolar disorder from schizophrenia during incentive decision making.
BACKGROUND
Abnormalities in incentive decision making, typically assessed using the Iowa Gambling Task (IGT), have been reported in both schizophrenia (SZ) and bipolar disorder (BD). We applied the Expectancy-Valence (E-V) model to determine whether motivational, cognitive and response selection component processes of IGT performance are differentially affected in SZ and BD.


METHODS
Performance on the IGT was assessed in 280 individuals comprising 70 remitted patients with SZ, 70 remitted patients with BD and 140 age-, sex- and IQ-matched healthy individuals. Based on the E-V model, we extracted three parameters, 'attention to gains or loses', 'expectancy learning' and 'response consistency', that respectively reflect motivational, cognitive and response selection influences on IGT performance.


RESULTS
Both patient groups underperformed in the IGT compared to healthy individuals. However, the source of these deficits was diagnosis specific. Associative learning underlying the representation of expectancies was disrupted in SZ whereas BD was associated with increased incentive salience of gains. These findings were not attributable to non-specific effects of sex, IQ, psychopathology or medication.


CONCLUSIONS
Our results point to dissociable processes underlying abnormal incentive decision making in BD and SZ that could potentially be mapped to different neural circuits.
DISM, Inter-University Centre for Behavioural Neurosciences (ICBN), University of Udine, Italy.
P
P
Brambilla
C
C
Perlini
M
M
Bellani
L
L
Tomelleri
A
A
Ferro
S
S
Cerruti
V
V
Marinelli
G
G
Rambaldelli
T
T
Christodoulou
J
J
Jogia
D
D
Dima
M
M
Tansella
M
M
Balestrieri
S
S
Frangou
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D059031:Anticipation, Psychological; D001245:Association Learning; D001288:Attention / Q000502:physiology; D001714:Bipolar Disorder / Q000523:psychology*; D016022:Case-Control Studies; D003657:Decision Making; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008960:Models, Psychological; D009042:Motivation / Q000502:physiology; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012201:Reward; D012559:Schizophrenia; D012565:Schizophrenic Psychology; D055815:Young Adult