Behavioral validation of avolition in schizophrenia

Are effort-based decision-making tasks worth the effort?-A study on the associations between effort-based decision-making tasks and self-report measures

OBJECTIVES

Amotivation is a common symptom in various mental disorders, including psychotic or depressive disorders. Effort-based decision-making (EBDM)-tasks quantifying amotivation at a behavioral level have been on the rise. Task performance has been shown to differentiate patient groups from healthy controls. However, findings on indicators of construct validity, such as the correlations between different tasks and between tasks and self-reported/observer-rated amotivation in clinical and healthy samples have been inconclusive.

METHODS

In a representative community sample (N = 90), we tested the construct validity of the Deck Choice Task, the Expenditure for Rewards Task and the Balloon Task. We calculated correlations between the EBDM-tasks and between the EBDM-tasks and self-reported amotivation, apathy, anticipatory pleasure, and BIS/BAS.

RESULTS

Correlations between tasks were low to moderate (0.198 ≤ r ≤ 0.358), with the Balloon Task showing the largest correlations with the other tasks, but no significant correlations between any EBDM-task and the self-report measures.

CONCLUSION

Although different EBDM-tasks are conceptualized to measure the same construct, a large part of what each task measures could not be accounted for by the other tasks. Moreover, the tasks did not appear to substantially capture what was measured in established self-report instruments for amotivation in our sample, which could be interpreted as questioning the construct validity of EBDM-tasks.

Low goal-directed behavior in negative symptoms is explained by goal setting - Results of a diary study

BACKGROUND AND OBJECTIVES

Engaging in goal-directed activities is a core difficulty of people with negative symptoms in schizophrenia. A previously developed goal pursuit model of negative symptoms (Schlier et al. 2017) postulates that negative symptom severity correlates with a tendency to set more avoidance- than approach-oriented goals. This shift in goal orientation correlates with low levels of goal expectancy, goal importance, and goal commitment. We explored whether these alterations translate into reduced goal-directed behavior (i.e., reduced goal striving and goal attainment).

METHODS

We conducted a one-week diary-study in a population sample (N=91). Participants were assessed for subclinical negative symptoms at baseline. Next, they set a daily goal and completed an online survey measuring goal orientation, goal characteristics, goal pursuit, and goal attainment once per day for one week.

RESULTS

Multilevel regression analyses and structural equation models showed that negative symptoms correlated with a tendency to set less approach-oriented goals with reduced goal expectancy and goal commitment. Goal orientation, expectancy, and commitment mediated the association between negative symptoms and reduced goal pursuit and attainment.

LIMITATIONS

We used a community sample, thus our results need to be replicated in a clinical sample of people with motivational negative symptoms.

CONCLUSIONS

Our results support the hypothesis that dysfunctional goal pursuit processes explain why negative symptoms lead to reduced goal-directed behavior. Interventions focusing on goal setting and goal expectations could be promising in improving goal-directed behavior in people with negative symptoms.

Avolition as the core negative symptom in schizophrenia: relevance to pharmacological treatment development

Negative symptoms have long been considered a core component of schizophrenia. Modern conceptualizations of the structure of negative symptoms posit that there are at least two broad dimensions (motivation and pleasure and diminished expression) or perhaps five separable domains (avolition, anhedonia, asociality, blunted affect, alogia). The current review synthesizes a body of emerging research indicating that avolition may have a special place among these dimensions, as it is generally associated with poorer outcomes and may have distinct neurobiological mechanisms. Network analytic findings also indicate that avolition is highly central and interconnected with the other negative symptom domains in schizophrenia, and successfully remediating avolition results in global improvement in the entire constellation of negative symptoms. Avolition may therefore reflect the most critical treatment target within the negative symptom construct. Implications for targeted treatment development and clinical trial design are discussed.

The demotivating effect of social exclusion: An experimental test of a psychosocial model on the development of negative symptoms in psychosis

The impairment in social functioning of patients with psychotic disorders is mainly driven by motivational negative symptoms with a widely unknown etiology. Building on the well-confirmed link between specific social risk factors and psychosis, the current study tested the postulated effect of immediate social exclusion on the development of motivational negative symptoms and the association of repeated social exclusion experiences with demotivating beliefs in a community sample (N = 84). Repeated social exclusion experiences and demotivating beliefs were assessed at baseline. We randomized the participants to either an exclusion or an inclusion condition of a virtual ball tossing game. Motivation and anticipatory pleasure were measured before and after the manipulation via self-report and via a behavioral effort paradigm. We found a significant multivariate effect of social exclusion on self-reported motivation (F(4,79) = 4.25, p < .01, η2 = .18), but not on behavioral effort (F(1,82) = 1.24, p = .27, η2 = .02). Repeated social exclusion was significantly associated with demotivating beliefs (r = .58, p < .01) and negative symptoms (r = .43, p < .001). Our findings support the notion that reduced motivation, anticipatory anhedonia and demotivating beliefs can be understood as motivational and cognitive consequences of social exclusion. We also discuss the implications for psychological interventions and for further research on the etiology of negative symptoms.

Combining actigraphy, ecological momentary assessment and neuroimaging to study apathy in patients with schizophrenia

BACKGROUND

Apathy can be defined as a reduction of goal-directed behavior and is a strong predictor for poor functional outcome in schizophrenia. However, no objective measure of apathy has been identified and assessment is limited to retrospective interview-based ratings. Here we aimed to identify more precise objective readouts of apathy for translational research and clinical practice.

METHODS

We employed a combined approach including interview-based ratings of the two negative symptom factors apathy and diminished expression, actigraphy based measures of spontaneous motor activity and the evaluation of daily activities using ecological momentary assessment. Furthermore, a functional magnetic resonance imaging task for reward anticipation was applied to investigate shared and divergent neural correlates of interview-based and behaviorally measured apathy.

RESULTS

We found in 18 schizophrenia patients with high interview-based apathy levels that motor activity was negatively correlated with apathy but not with diminished expression. In contrast, measures of daily activities were not associated with apathy. Neural activation during reward anticipation revealed an association between hypoactivation of the ventral striatum and interview-based apathy as well as hypoactivation of the inferior frontal gyrus and motor activity level.

CONCLUSIONS

Spontaneous motor activity is an objective readout of apathy, which was specific and not present for diminished expression. On a neural level, interview-based and objective measures of apathy showed divergent neural correlates in the cortical-striatal network, which suggests dissociable neural processes. Finally, motor activity provides a promising readout for quantifying apathy in both translational research and clinical practice.

An investigation into the drivers of avolition in schizophrenia

Over a century of research has documented that avolition is a core symptom in schizophrenia. However, the drivers of avolition remain unclear. Conceptually, there are at least two potential mutually compatible drivers that could cause avolition in schizophrenia. First, people with schizophrenia might have differences in preferences that result in less goal-directed behavior than non-clinical populations (preference-differences). Second, people with schizophrenia might have difficulty translating their preferences into manifest behavior at rates similar to non-clinical populations (psychological-inertia). In the present work, we modified and validated a well-validated paradigm from the motivation/decision making literature to compare levels of preference-differences and psychological-inertia. To measure preference-differences, people with and without schizophrenia choose between a lower-valenced and higher-valenced image. We measured the rate at which the normatively lower-valenced image was preferred. To measure psychological-inertia, both groups were given the opportunity to volitionally switch from a lower-valenced image and view a higher-valenced image. Contrary to expectations, people with schizophrenia did not differ on either preference-differences or psychological-inertia. Statistical analysis revealed that the possibility of a Type II error for even a weak effect was small. The present data suggest new avenues for research investigating mechanisms underlying avolition and clinical interventions targeting avolition in schizophrenia.

Using Functional Analysis as a Framework to Guide Individualized Treatment for Negative Symptoms

Although numerous interventions are available for negative symptoms, outcomes have been unsatisfactory with pharmacological and psychological interventions producing changes of only limited clinical significance. Here, we argue that because negative symptoms occur as a complex syndrome caused and maintained by numerous factors that vary between individuals they are unlikely to be treated effectively by the present "one size fits all" approaches. Instead, a well-founded selection of those interventions relevant to each individual is needed to optimize both the efficiency and the efficacy of existing approaches. The concept of functional analysis (FA) can be used to structure existing knowledge so that it can guide individualized treatment planning. FA is based on stimulus-response learning mechanisms taking into account the characteristics of the organism that contribute to the responses, their consequences and the contingency with which consequences are tied to the response. FA can thus be flexibly applied to the level of individual patients to understand the factors causing and maintaining negative symptoms and derive suitable interventions. In this article we will briefly introduce the concept of FA and demonstrate-exemplarily-how known psychological and biological correlates of negative symptoms can be incorporated into its framework. We then outline the framework's implications for individual assessment and treatment. Following the logic of FA, we argue that a detailed assessment is needed to identify the key factors causing or maintaining negative symptoms for each individual patient. Interventions can then be selected according to their likelihood of changing these key factors and need to take interactions between different factors into account. Supplementary case vignettes exemplify the usefulness of functional analysis for individual treatment planning. Finally, we discuss and point to avenues for future research guided by this model.

Individual negative symptoms and domains - Relevance for assessment, pathomechanisms and treatment

The negative symptoms of schizophrenia can be divided into two domains. Avolition/apathy includes the individual symptoms of avolition, asociality and anhedonia. Diminished expression includes blunted affect and alogia. Until now, causes and treatment of negative symptoms have remained a major challenge, which is partially related to the focus on negative symptoms as a broad entity. Here, we propose that negative symptoms may become more tractable when the different domains and individual symptoms are taken into account. There is now increasing evidence that the relationship with clinical variables - in particular outcome - differs between the domains of avolition/apathy and diminished expression. Regarding models of negative symptom formation, those relevant to avolition/apathy are now converging on processes underlying goal-directed behavior and dysfunctions of the reward system. In contrast, models of the diminished expression domains are only beginning to emerge. The aim of this article is to review the specific clinical, behavioral and neural correlates of individual symptoms and domains as a better understanding of these areas may facilitate specific treatment approaches.

The translational study of apathy-an ecological approach

Apathy, a quantitative reduction in goal-directed behavior, is a prevalent symptom dimension with a negative impact on functional outcome in various neuropsychiatric disorders including schizophrenia and depression. The aim of this review is to show that interview-based assessment of apathy in humans and observation of spontaneous rodent behavior in an ecological setting can serve as an important complementary approach to already existing task-based assessment, to study and understand the neurobiological bases of apathy. We first discuss the paucity of current translational approaches regarding animal equivalents of psychopathological assessment of apathy. We then present the existing evaluation scales for the assessment of apathy in humans and propose five sub-domains of apathy, namely self-care, social interaction, exploration, work/education and recreation. Each of the items in apathy evaluation scales can be assigned to one of these sub-domains. We then show that corresponding, well-validated behavioral readouts exist for rodents and that, indeed, three of the five human apathy sub-domains have a rodent equivalent. In conclusion, the translational ecological study of apathy in humans and rodents is possible and will constitute an important approach to increase the understanding of the neurobiological bases of apathy and the development of novel treatments.

Adjunctive Minocycline in Clozapine-Treated Schizophrenia Patients With Persistent Symptoms

OBJECTIVE

Clozapine is the most effective antipsychotic for treatment refractory people with schizophrenia, yet many patients only partially respond. Accumulating preclinical and clinical data suggest benefits with minocycline. We tested adjunct minocycline to clozapine in a 10-week, double-blind, placebo-controlled trial. Primary outcomes tested were positive, and cognitive symptoms, while avolition, anxiety/depression, and negative symptoms were secondary outcomes.

METHODS

Schizophrenia and schizoaffective participants (n = 52) with persistent positive symptoms were randomized to receive adjunct minocycline (100 mg oral capsule twice daily; n = 29) or placebo (n = 23).

RESULTS

Brief Psychiatric Rating Scale (BPRS) psychosis factor (P = 0.098; effect size [ES], 0.39) and BPRS total score (P = 0.075; ES, 0.55) were not significant. A change in total BPRS symptoms of more than or equal to 30% was observed in 7 (25%) of 28 among minocycline and 1 (4%) of 23 among placebo participants, respectively (P = 0.044). Global cognitive function (MATRICS Consensus Cognitive Battery) did not differ, although there was a significant variation in size of treatment effects among cognitive domains (P = 0.03), with significant improvement in working memory favoring minocycline (P = 0.023; ES, 0.41). The Scale for the Assessment of Negative Symptoms total score did not differ, but significant improvement in avolition with minocycline was noted (P = 0.012; ES, 0.34). Significant improvement in the BPRS anxiety/depression factor was observed with minocycline (P = 0.028; ES, 0.49). Minocycline was well tolerated with significantly fewer headaches and constipation compared with placebo.

CONCLUSIONS

Minocycline's effect on the MATRICS Consensus Cognitive Battery composite score and positive symptoms were not statistically significant. Significant improvements with minocycline were seen in working memory, avolition, and anxiety/depressive symptoms in a chronic population with persistent symptoms. Larger studies are needed to validate these findings.

Amotivation in schizophrenia: integrated assessment with behavioral, clinical, and imaging measures

Motivational deficits play a central role in disability caused by schizophrenia and constitute a major unmet therapeutic need. Negative symptoms have previously been linked to hypofunction in ventral striatum (VS), a core component of brain motivation circuitry. However, it remains unclear to what extent this relationship holds for specific negative symptoms such as amotivation, and this question has not been addressed with integrated behavioral, clinical, and imaging measures. Here, 41 individuals with schizophrenia and 37 controls performed a brief, computerized progressive ratio task (PRT) that quantifies effort exerted in pursuit of monetary reward. Clinical amotivation was assessed using the recently validated Clinical Assessment Interview for Negative Symptoms (CAINS). VS function was probed during functional magnetic resonance imaging using a monetary guessing paradigm. We found that individuals with schizophrenia had diminished motivation as measured by the PRT, which significantly and selectively related to clinical amotivation as measured by the CAINS. Critically, lower PRT motivation in schizophrenia was also dimensionally related to VS hypofunction. Our results demonstrate robust dimensional associations between behavioral amotivation, clinical amotivation, and VS hypofunction in schizophrenia. Integrating behavioral measures such as the PRT will facilitate translational efforts to identify biomarkers of amotivation and to assess response to novel therapeutic interventions.

Negative symptoms, past and present: a historical perspective and moving to DSM-5

The diagnosis of schizophrenia includes "positive" and "negative" symptoms. These titles were developed to respectively reflect if the symptoms are additions to normal experiences, such as delusions and hallucinations, or if they refer to the absence or the loss of normal emotional function or behavior. This paper describes the history of the negative symptom concept, from its origins up to the considerations for the DSM-5, including the steps that produced the current conceptualizations. The DSM-5 only includes deficits in emotional expression and avolition as negative symptoms, which can be assessed from interview information. Factor analyses show they encompass most other negative symptom items. In addition to using these negative symptoms in a categorical manner to make a diagnosis, the DSM-5 has quantitative severity ratings of the negative symptoms, along with ratings of delusions, cognitive symptoms, motor symptoms, disorganization, depression and mania. With this approach, the different symptom domains, including negative symptoms, can be measured and tracked over time. Another change in the DSM-5 is the dropping of the schizophrenia subtypes that have been included in earlier volumes, as they were not useful in treatment decisions or prognosis. An intended outcome of these changes in DSM-5 is for clinicians to directly treat the individual psychopathological domains of the disorder for optimizing individual outcomes. Finally, this paper includes descriptions of the negative symptom items from over a dozen different scales.

Amotivation and functional outcomes in early schizophrenia

Negative symptoms, particularly amotivation/apathy, are intimately tied to functional outcomes. In the present study, apathy strongly predicted psychosocial functioning in a sample of early course schizophrenia patients. This relationship remained robust even after controlling for other clinical variables. These data suggest amotivation is core to functioning across the disease course.

Inpatients with schizophrenia report impaired situational motivation but intact global and social motivation

It is well established that individuals with schizophrenia are less active and engaged than healthy control subjects, and motivation deficits are considered a core symptom of the disease. However, it remains unclear if schizophrenia individuals perceive themselves as less motivated than others, and there is a scarcity in research examining the relationship between perceived motivation, psychopathology and personality traits. Eighty-six inpatients with schizophrenia and 45 non-patient control participants completed the Motivation and Energy Inventory, which consists of Global Motivation, Social Motivation and Situational Motivation (the motivation individuals experience when they are engaging in an activity). Participants also completed personality questionnaires and an affective evocative task. Compared to controls, schizophrenia participants reported lower situational motivation, and comparable global and social motivation. Situational motivation was negatively predicted by negative temperament, affective ambivalence and depression level. Our results are consistent with the idea that schizophrenia individuals are not impaired in their motivational disposition but lack energy during the implementation of their goals. This may reflect impairment in the prediction, maintenance and/or modulation of required effort and energy during goal-directed actions, and is predicted by some affective processes. Improving situational motivation may be an effective therapeutic approach in people with schizophrenia.

Incentive motivation deficits in schizophrenia reflect effort computation impairments during cost-benefit decision-making

BACKGROUND

Motivational impairments are a core feature of schizophrenia and although there are numerous reports studying this feature using clinical rating scales, objective behavioural assessments are lacking. Here, we use a translational paradigm to measure incentive motivation in individuals with schizophrenia.

METHODS

Sixteen stable outpatients with schizophrenia and sixteen matched healthy controls completed a modified version of the Effort Expenditure for Rewards Task that accounts for differences in motoric ability. Briefly, subjects were presented with a series of trials where they may choose to expend a greater amount of effort for a larger monetary reward versus less effort for a smaller reward. Additionally, the probability of receiving money for a given trial was varied at 12%, 50% and 88%. Clinical and other reward-related variables were also evaluated.

RESULTS

Patients opted to expend greater effort significantly less than controls for trials of high, but uncertain (i.e. 50% and 88% probability) incentive value, which was related to amotivation and neurocognitive deficits. Other abnormalities were also noted but were related to different clinical variables such as impulsivity (low reward and 12% probability). These motivational deficits were not due to group differences in reward learning, reward valuation or hedonic capacity.

CONCLUSIONS

Our findings offer novel support for incentive motivation deficits in schizophrenia. Clinical amotivation is associated with impairments in the computation of effort during cost-benefit decision-making. This objective translational paradigm may guide future investigations of the neural circuitry underlying these motivational impairments.

Neural substrates underlying effort computation in schizophrenia

The lack of initiative, drive or effort in patients with schizophrenia is linked to marked functional impairments. However, our assessment of effort and motivation is crude, relying on clinical rating scales based largely on patient recall. In order to better understand the neurobiology of effort in schizophrenia, we need more rigorous measurements of this construct. In the behavioural neuroscience literature, decades of work has been carried out developing various paradigms to examine the neural underpinnings of an animal's willingness to expend effort for a reward. Here, we shall review this literature on the nature of paradigms used in rodents to assess effort, as well as those used in humans. Next, the neurobiology of these effort-based decisions will be discussed. We shall then review what is known about effort in schizophrenia, and what might be inferred from experiments done in other human populations. Lastly, we shall discuss future directions of research that may assist in shedding light on the neurobiology of effort cost computations in schizophrenia.

[The clinic of apathy in schizophrenia: a critical review of the issue]

INTRODUCTION

Today the concept of apathy is subject to many questions. This psychological state is present and predominant in different disorders such as neurodegenerative and psychiatric diseases or neurological acquired disorders. Apathy is a part of the clinical vocabulary, however, we can note that in the literature there remains confusion in its definition, and we can find an amalgam with other clinical symptoms.

OBJECTIVES

The aim of this review is to provide a clarification of the concept of apathy in clinical practice in schizophrenia as well as to highlight the gaps that exist.

LITERATURE FINDINGS

Apathy belongs to the negative symptoms of schizophrenia. For its understanding, it is necessary to define apathy as a multidimensional syndrome (cognitive, emotional, and behavioral) manifesting as a quantitative reduction of voluntary behaviors directed toward one or several goals. However, at present, we are witnessing a reductionist and simplistic conception of the syndrome of apathy and this especially in the Anglo-Saxon literature. Several authors reduce apathy to its behavioral component, so in other words, to avolition/amotivation. Avolition refers to a loss of self-initiated and spontaneous behaviors. In this definition only observable behavior is taken into account and not the underlying mechanisms (cognitive and emotional). In order to understand the syndrome of apathy, it is necessary to have a holistic and multidimensional outlook. Some authors have proposed diagnostic criteria for apathy by taking into account the different dimensions of apathy. Moreover not only is apathy confused with avolition, but it is also still difficult to distinguish it from depression. Apathy and depression share common clinical signs (i.e. loss of interest), but they also have distinct clinical signs (lack of motivation for apathy, and suicidal ideation for depression). Authors have shown that the presence of one symptom (apathy or depression) does not predict the presence of the other. An apathetic patient does not have to be necessarily in a depressive state and vice versa. However, to our knowledge, there is no data capable of distinguishing depression from apathy in schizophrenia, and knowing what is the part of one and the other when the patient has both symptoms. In addition, we can see that the confusion that persists between those two symptoms also stems from assessment tools. Indeed, some assessment tools such as the Montgomery and Asberg Depression Rating Scale (MARDS) have an apathy subscale. Therefore, this scale does not only evaluate depression. Regarding the assessment of apathy in schizophrenia, there are specific and nonspecific tools. Nonspecific tools define apathy differently. For this reason, authors have proposed to measure apathy by using analytic factors of negative symptoms. In this case, apathy is going to be assessed by the factor "motivation/pleasure" including anhedonia, asociality and avolition. This factor will provide the possibility of a better assessment of apathy. Concerning specific scales (like AES), there are gaps such as a lack of standardization in the execution and the quotation. Furthermore, no scale takes into account the factors causing apathy.

CONCLUSION

Knowing the reasons for apathy is necessary because this syndrome is frequent in schizophrenia, and it is found in the different phases of this disease (prodromal, first episode psychosis, and chronic). In addition, apathy has significant functional consequences on the patient's quality of life, as well as on his or her global functioning. Indeed, apathy impacts on his or her social and professional life. Patients with schizophrenia have a loss of autonomy, less employment and social withdrawal. Consequently, interest in its drug or treatment it is obvious. However, drug and non-drug treatments are not specific to apathy and therefore little effective on this syndrome. Implications to stimulate future research are presented.