Too much or too little? Exploring effort perception in schizophrenia within the framework of motivational intensity theory

Pupillary responses as a biomarker of cognitive effort and the impact of task difficulty on reward processing in schizophrenia

Negative symptoms of schizophrenia robustly predict functional outcomes but remain relatively resistant to available treatments. Better measures of negative symptoms, especially motivational deficits, are needed to better understand these symptoms and improve treatment development. Recent research shows promise in linking behavioral effort tasks to motivational negative symptoms, reward processing deficits, and defeatist attitudes, but few studies account for individual or group (patient v. control) differences in cognitive ability to perform the tasks. Individuals with poorer abilities might be less motivated to perform tasks because they find them more difficult to perform. This study used a personalized digit span task to control task difficulty while measuring task effort via pupillary responses (greater dilation indicates greater cognitive effort) at varying monetary rewards ($1 & $2). Participants with schizophrenia (N = 34) and healthy controls (N = 41) performed a digit span task with personalized max span lengths and easy (max- 2 digits) and overload (max+ 2 digits) conditions. Consistent with many studies, pupillary responses (cognitive effort) increased with greater difficulty until exceeding capacity. A similar pattern of reward responsivity was seen in both groups, such that greater reward increased dilation (effort) comparably for both groups when difficulty was within capacity. Neither patients nor controls exerted increased effort for greater reward when difficulty exceeded capacity. In patients, positive relationships were found between pupil dilation and defeatist performance beliefs if task difficulty was within capacity; a relationship that reversed if the task was too difficult. The findings demonstrate the importance of accounting for cognitive capacity and task difficulty when evaluating motivation and reward sensitivity and illustrate the utility of pupillary responses as an objective measure of effort in schizophrenia.

Somatic health according to people with severe mental disease

OBJECTIVES

Patients with schizophrenia have a 15- to 20-year shorter life expectancy compared with the general population. The aim of this study was to explore these patients' perception of their physical health.

METHODS

A patient reported outcomes measure (PROM) has been developed by patients with severe mental disease. This survey had to better capture undetected, under-rated and non-prioritized physical domains by traditional routine clinical scales that are important for people who live with mental health disease. These patients have tested the applicability of this PROM with peers with severe mental disease in medical, social and community-based centers from Hauts-de-France.

RESULTS

Two and a half years have been required to develop this PROM, to test its applicability to patients with severe mental disease and to analyze the results. The study process has been slowed by the sanitary context induced by the COVID-19 pandemic. Thirty-two questionnaires have been collected by the participants. Despite this low number of data, participants have been satisfied by the results and their experience. The results show that people with severe mental disease consider physical health as a major concern, notably pain and somatic diseases. External factors (such as accessibility to health care and medication) and internal factors (such as self-esteem, cognitive and negative symptoms, sleep, alimentation, and substance use) have been identified as barriers for physical health.

CONCLUSIONS

These results support the development of PROMs highlighting personal experience of people with severe mental disease. The data obtained thanks to these measures will allow to build programs to help them to cope with barriers for physical health.

Effort and effort discounting as predictors of seeking psychotherapy among individuals with depression

OBJECTIVES

Many individuals who experience depression do not seek psychotherapy, and past research has had limited success in predicting help-seeking in this population. Accounting for behavioral characteristics of depression that affect help-seeking decisions, such as effort discounting (devaluation of rewards as a function of effort), may address this gap.

METHODS

Individuals with moderate-severe depression symptoms who were not in psychotherapy (N = 253) reported their depression symptom severity and the amount of effort they anticipated seeking psychotherapy would require; they also completed a behavioral measure of effort discounting. At a 3-month follow-up, they reported whether they initiated psychotherapy during the follow-up period.

RESULTS

Depression symptom severity was associated with perceptions that seeking psychotherapy would be more effortful. In turn, perceptions that seeking psychotherapy would be more effortful prospectively predicted a lower likelihood of initiating psychotherapy. Effort discounting was unrelated to psychotherapy use.

CONCLUSIONS

These results suggest that differences in the anticipated effort required to seek psychotherapy can increase depressed individuals' risk of going untreated. Future research may test whether reducing the effort of seeking psychotherapy increases psychotherapy use among those with depression. For instance, streamlining insurance enrollment procedures, implementing patient decision aids, or offering telehealth treatment options may be beneficial.

Effort-Cost Decision-making Among Individuals With Schizophrenia: A Systematic Review and Meta-analysis

Importance

Motivational impairments in schizophrenia are by definition associated with poor outcome. It is postulated that the reduction of goal-directed behavior arises from abnormal trade-offs between rewards and efforts.

Objective

To examine whether schizophrenia is associated with impairments in effort-cost decision-making.

Data Sources

For this systematic review and meta-analysis, the PubMed, ScienceDirect, PsycINFO, Embase, and ClinicalTrials.gov databases were searched from inception to July 2022 for studies that investigated effort-cost decision-making in schizophrenia. Search terms included effort, cost, and schizophrenia.

Study Selection

Consensual criteria for inclusion were peer-reviewed studies published in English that used a computerized effort-cost decision-making behavioral paradigm and compared individuals with schizophrenia with control individuals.

Data Extraction and Synthesis

The Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline was used for abstracting data. Data were extracted independently by 2 authors and then pooled using random-effects sizes and bayesian approaches.

Main Outcomes and Measures

The main outcomes were performance on effort-cost decision-making tasks requiring an effort-reward trade-off, measured by Hedges g effect size. Effects of moderators were tested with meta-regressions and subgroup analyses.

Results

Twenty studies involving 1503 participants were included: 837 individuals with schizophrenia (541 [64.6%] male; mean [SD] age, 35.89 [6.70] years) and 666 control individuals without schizophrenia (360 [54.1%] male; mean [SD] age, 34.16 [5.92] years). Participants with schizophrenia had significantly reduced willingness to expend effort for rewards compared with controls (k = 20; effect size, 0.43; 95% CI, 0.30-0.56; P < .001; I2 = 33.1%; Q test P = .08). The magnitude of the deficit was significantly greater for high-reward trials. The severity of negative symptoms was negatively associated with effort-cost decision-making (k = 8; effect size, -0.33; 95% CI, -0.50 to -0.15; P < .001), while participants with a high number of negative symptoms had a significantly larger impairment in effort-cost decision-making (k = 5; effect size, 0.47; 95% CI, 0.10-0.84; P = .01).

Conclusions and Relevance

In this systematic review and meta-analysis, schizophrenia was associated with deficits in effort allocation as indexed by effort-cost decision-making tasks. Understanding the cognitive and neurobiological mechanisms driving effort allocation impairments may assist in developing novel interventions.

Perception of effort and the allocation of physical resources: A generalization to upper-limb motor tasks

Purpose

The perception of effort (PE) is widely used to prescribe and monitor exercise during locomotor and resistance tasks. The present study examines the validity of PE to prescribe and monitor exercise during upper-limb motor tasks under various loads and speed requirements.

Methods

Forty participants volunteered in two experiments. In experiment 1, we used four PE intensities to prescribe exercise on a modified version of the box and block test (BBT) and a pointing task. We investigated the possibility of monitoring the exercise intensity by tracking changes in PE rating in response to three different tempos or additional weights. Experiment 2 replicated the possibility of prescribing the exercise with the PE intensity during the BBT and explored the impact of additional weights on performance and PE during the standardized version of the BBT. Muscle activation, heart rate, and respiratory frequencies were recorded.

Results

In experiment 1, increasing the PE intensity to prescribe exercise induced an increased performance between each intensity. Increasing task difficulty with faster movement tempo and adding weight on the forearm increased the rating of PE. Experiment 2 replicated the possibility to use PE intensity for exercise prescription during the BBT. When completing the BBT with an additional weight on the forearm, participants maintained performance at the cost of a higher PE. In both experiments, changes in PE were associated with changes in muscle activation.

Conclusion

Our results suggest that PE is a valid tool to prescribe and monitor exercise during upper-limb motor tasks.

Effort-based decision making in schizotypy and its relationship with amotivation and psychosocial functioning

INTRODUCTION

Suboptimal effort-based decision-making with reduced willingness to expend effort for high-probability/high-value reward is observed in schizophrenia patients and is related to diminished motivation, but is understudied in schizotypy. This study aimed to examine effort-allocation in schizotypy individuals and its association with amotivation and psychosocial functioning.

METHODS

We recruited 40 schizotypy individuals and 40 demographically-matched healthy controls, based on Schizotypal Personality Questionnaire-Brief (SPQ-B) score (top and bottom 10% SPQ-B scores, respectively), from 2400 young people aged 15-24 years participating a population-based mental health survey in Hong Kong and examined effort-allocation using the Effort Expenditure for Reward Task (EEfRT). Negative / amotivation symptoms and psychosocial functioning were assessed by the Brief Negative Symptom Scale (BNSS) and the Social Functioning and Occupational Assessment Scale (SOFAS), respectively. Schizotypy individuals were categorized into high-amotivation and low-amotivation groups based on a median-split of BNSS amotivation domain score.

RESULTS

Our results showed no main group effect (in either two or three-group comparison) on effort task performance. Three-group comparison analyses on selected EEfRT performance indices revealed that high-amotivation schizotypy individuals displayed significantly less increase in effortful options from low-value to high-value reward (reward-difference score) and from low-probability/low-value to high-probability/high-value reward (probability/reward-difference score) than low-amotivation individuals and controls. Correlation analyses demonstrated trend-wise significance between BNSS amotivation domain score and several EEfRT performance indices in schizotypy group. Schizotypy individuals with poorer psychosocial functioning tended to exhibit smaller probability/reward-difference score relative to other two groups.

DISCUSSION

Our findings indicate subtle effort-allocation abnormalities in schizotypy individuals with high levels of diminished motivation, and suggest the link between laboratory-based effort-cost measures and real-world functional outcome.

Getting a tool gives wings even in schizophrenia: underestimation of tool-related effort in a motor imagery task

Humans frequently use tools to reduce action-related efforts. Interestingly, several studies have demonstrated that individuals had tool-related biases in terms of perceived effort reduction during motor imagery tasks, despite the lack of evidence of real benefits. Reduced effort allocation has been repeatedly found in schizophrenia, but it remains unknown how schizophrenia patients perceive tool-related benefits regarding effort. Twenty-four schizophrenia patients and twenty-four nonclinical participants were instructed to move the same quantities of objects with their hands or with a tool in both real and imagined situations. Imagined and real movement durations were recorded. Similarly to nonclinical participants, patients overestimated tool-related benefits and underestimated tool-related effort in terms of time when they mentally simulated a task requiring the use of a tool. No association between movement durations and psychotic symptoms was found. Our results open new perspectives on the issue of effort in schizophrenia.