Reference and sample | Paradigm | Patient vs control differences? | Association with negative symptoms? | Association with functioning? | Association with other symptoms? | Association with cognition? |
---|---|---|---|---|---|---|
Physical effort: hand grip | ||||||
Hartmann et al33 : 31 SCZ/ SAD mixed in- and outpatients; 20 controls | Handgrip task: 4 effort levels (with individual titration) and 5 reward levels. Dependent variables: Computed indifference points for each effort level and overall area under the curve (AUC): Paid out 5 random trials | N/A | Yes: Continuous and categorical Total symptoms: N/A Experiential symptoms: AUC correlated with BNSS and SANS apathy factors. Using median split on BNSS apathy factor and 4 indifference points, found significant group and effort level effects with trend-level interaction: high apathy group showed greater discounting than low apathy and control groups. Expressive symptoms: No associations |
Yes: Lower Personal and Social Performance Scale correlated with AUC | No: PANSS, CDSS | No: Composite of verbal learning, verbal and visual working memory, processing speed, planning, and semantic/ phonemic fluency tests |
Docx et al32 : 40 SCZ (status not specified); 39 controls | Handgrip task: 6 effort levels (with individual titration) and reward adjusted to identify indifference points. Separate choice and execution blocks. Told would receive cash bonus based on performance—all actually paid small bonus | No. Groups comparable on indifference points | No Total symptoms: SANS total median split; No difference for indifference points Experiential symptoms; No continuous or categorical differences for anhedonia and avolition subscales Expressive symptoms: N/A |
N/A | N/A | No: Composite or working memory, attentional vigilance, and processing speed tasks |
Physical effort: Button pressing | ||||||
Fervaha et al28 : 16 SCZ outpatients; 16 controls | Effort Expenditure for Reward Task: 2 reward levels and 3 probability levels (12, 50, 88%). Button presses required for hard and easy tasks | individually titrated. 20min time limit. Payout information not specified. Dependent variable: percent hard choices | Yes: Group X reward and Group X probability interactions, no 3-way interaction. For low reward trials, patients selected more hard choices at 12% but not at 50 or 88%; for high reward trials, patients selected less hard choices at 50 and 88% but not at 12% | No Total symptoms: SANS and Apathy Evaluation Scale- clinician not associated with hard choices in the 50% or 88% conditions. Experiential symptoms: N/A Expressive symptoms: N/A |
No: Quality of Life Scale— abbreviated | No: SAPS | No: MCCB |
Gold et al31 : 44 SCZ/SAD primarily outpatients; 36 controls | Balloon Effort Task: 5 reward levels and 2 probability levels (50, 100%). Button presses required for hard and easy tasks not individually titrated. Participants told they would receive cash bonus based on performance and were given a standard bonus amount. Dependent variable: percent hard choices | Yes: Group X probability interaction, trend for group x reward interaction, no 3-way interaction. Patients selected fewer hard tasks than controls at the highest reward levels in the 100% condition, but no group differences at 50% | Yes: Categorical Total symptoms: Median split on BNSS Total score - high negative symptoms group had fewer hard choices than controls at highest reward level in 100% condition (no differences between low negative symptoms group and controls). Correlational analyses for BNSS total were nonsignificant. Experiential symptoms: Correlational and median split analyses for BNSS avolition and anhedonia items were nonsignificant. Expressive symptoms: N/A |
N/A | No: BPRS | Yes: Higher MCCB scores correlated with more hard choices at highest reward levels |
Barch et al29 : 59 SCZ/SAD outpatients; 39 controls | Effort Expenditure for Rewards Task: 4 reward levels and 2 probability levels (50%, 88%.); Button presses for hard and easy tasks not individually titrated. 15 minute time limit. Two random trials rewarded. Dependent variable: percent hard choices | Yes. Group X reward and Group X probability interactions, no 3-way interaction. Patients chose fewer hard tasks than controls at higher reward and probability levels | Yes: Continuous Total Symptoms: N/A Experiential Symptoms: Items from SANS and BNSS combined to create composite Avolition and Anhedonia scales. Higher avolition correlated with fewer hard choices in 88% condition and with smaller increases in hard choices from 50–88% conditions Expressive symptoms: N/A |
Yes: Better SLOF community and work functioning associated with more hard choices in 88% and in highest reward level | Yes: SAPS positive and disorganization symptoms | N/A |
Treadway et al30 : 12 SCZ outpatients; 15 controls | Effort Expenditure for Rewards Task: 4 reward levels and 3 probability levels (12%, 50%, 88%.). Button presses for hard and easy tasks not individually titrated. Time limit and payout information not specified. Dependent variable: percent hard choices | Yes: Group X reward and Group X probability interactions, no 3-way interaction. Patients chose fewer hard tasks than controls at higher reward and probability levels | Yes: Continuous Total Symptoms: Trend for correlation between higher SANS and lower scores on a summary index of ability to incorporate reward and probability information. Experiential symptoms: N/A Expressive symptoms: N/A |
N/A | N/A | N/A |
Cognitive effort | ||||||
Wolf et al34 : 41 SCZ outpatients; 37 controls | Cognitive effort progressive ratio task. Seven sets of trials (identify which of 2 numbers is bigger) at each of 3 reward levels. Number of correct responses to receive a reward increased within each successive trial set for each reward levels. Participants paid what they earn. Dependent variable: Break point | Yes: Patients had lower breakpoints than controls | Yes: Continuous Total Symptoms: N/A Experiential Symptoms: Higher CAINS amotivation items correlated with lower breakpoint. Expressive Symptoms: No associations |
N/A | N/A | N/A |
Gold et al35 : 83 SCZ/SAD outpatients; 71 controls across 3 experiments | Series of studies using different version of the Demand Selection Task in Experiments (implicit selection task for stimuli associated with frequent [hard choice] or infrequent [easy choice] set-shifting demands): (1) standard instructions, (2) more explicit instructions, (3) further instruction and parameter changes. No monetary rewards involved. Dependent variable: percent hard choices | Mixed: Experiments: (1) No effort related effects for either group, (2) Less effort avoidance in patients, (3) No group differences in effort avoidance | No Total symptoms: BNSS and SANS total scores not associated with effort aversion in each experiment and in combined sample. Experiential Symptoms: BNSS, SANS avolition and anhedonia subscales not associated with effort aversion in each experiment and in combined sample. Expressive symptoms: N/A |
N/A | No: BPRS | Yes: Higher MCCB and WASI correlated with more effort discounting in the total combined sample |
Notes: BNSS, Brief Negative Symptom Scale; BPRS, Brief Psychiatric Rating Scale; CDSS, Calgary Depression Scale for Schizophrenia; CAINS, Clinical Assessment Interview for Negative Symptoms; MCCB, MATRICS Consensus Cognitive Battery; N/A, not assessed; PANSS, Positive and Negative Symptom Scale; SAD, schizoaffective disorder; SANS, Scale for the Assessment of Negative Symptoms; SCZ, schizoaffective disorder; SLOF, Specific Levels of Functioning Scale; WASI, Wechsler Abbreviated Scale for Intelligence.