Missing the Sweet Spot Disengagement in Schizophrenia

Abstract

The extent to which an individual engages in a cognitive task is associated with performance in laboratory settings¹ and a variety of domains of functioning, such as athletic activity and artistic expression.² The neural circuitry associated with task engagement is in the process of being elucidated by cognitive neuroscience investigations. These newly acquired data provide an opportunity to understand the cognitive, social, and functional disabilities that lie at the core of dysfunction in patients with schizophrenia. This article describes the importance of task engagement in human functioning, its impairment in schizophrenia, and the possibility that disengagement during late adolescence may herald future development of schizophrenia.^3,4 Since treatment studies suggest that improvement in this aspect of cognitive functioning has the potential to improve the functioning of patients with schizophrenia in various domains, it is possible that these improvements may be mediated by improved engagement with external processes, including social processes and patient-clinician relationships, leading to improved therapeutic alliance and increased treatment adherence.

Task Engagement and Healthy Human Function: The “Sweet Spot” of Everyday Life

Learning any task that is complex enough to be relevant to human functioning requires a variety of different cognitive skills. For instance, when humans learn how to perform a complex motor task, such as swinging a golf club, attention, executive functions, motor skills, and learning abilities are required. Posner and Rothbart⁵ described three stages of how attention changes during practice-related learning. In the first stage, referred to as the cognitive stage, an individual engages with a task by figuring out how to perform it. In the next stage, the associative stage, the act becomes ingrained through repeated practice and the development of mental associations between the complex activity and simpler thoughts. Consolidating mental plans into a single thought is more efficient, reduces mental energy devoted to planning, and allows motor activity to be experienced as effortless. Finally, in the autonomous stage, activity becomes less directly subject to cognitive control. Activity in this stage is experienced as automatic, and it becomes less subject to interferences from other ongoing activities or distracting influences.

These cognitive stages are associated with important neural circuitry changes. Human and non-human animal studies have demonstrated that during the course of motor learning, neural circuits that mediate motor function shift from more anterior processes, such as dorsolateral prefrontal cortical functioning, to more posterior and subcortical systems, such as motor cortex, cerebellum, and basal ganglia.^6–10 In addition, as tasks become learned or overlearned, trust in the accuracy of the performance is developed with a resulting reduction in anterior cingulate activation and a shift from ventral to dorsal systems.¹¹ A particularly striking example of this shift from anterior to posterior brain systems has been demonstrated in functional MRI studies. Subjects who performed a working memory task had decreased activation of the DLPFC and right superior parietal cortical activation following practice of the task.¹⁰ In this manner, increased practice reduces task difficulty and changes the way that an individual engages with a task. The implication of this research is that the human brain expends effort in response to cognitive challenges in the manner of an inverted U-shaped curve (Figure 1): Easy tasks do not require full engagement, yet more difficult tasks increase the effort and engagement level required for successful performance. However, as tasks are learned, the amount of engagement that is required reduces. This reduction is associated with decreased activation of prefrontal systems, referred to as efficiency.¹²

Figure 1.

The relationship between task difficulty and level of engagement for new and learned tasks

While learning studies provide an opportunity to explore the ascending arm of the inverted U-shaped curve, the descending arm of the curve has been explored by work on task disengagement. In a series of studies using pupilography,^1,13 pupil size has been found to be associated with task engagement and improved performance. On a variety of cognitive tasks, healthy control subjects demonstrate increased pupil size as task difficulty moves from easy to moderate difficulty. However, as task difficultly increases to the point in which subjects are unable to perform the task, pupil size decreases, sometimes abruptly.¹³ This model of the relationship between task engagement and performance has been demonstrated in several cognitive domains, such as tests of working memory and processing speed.

The implications of these findings can be found in many real-world situations. The ability to stay engaged in task performance is a fundamental component of success in various vocational and avocational domains. Csikszentmihalyi¹⁴ conducted a series of experiments describing that humans experience optimal task engagement when skills and task challenges are well balanced. Artists and athletes frequently describe a strong relationship between their best performances or creations and an absorption with the process of performing or creating.² Furthermore, the experience of being fully engaged in a task is often described as blissful, joyful, and meaningful with various terms such as flow, in the zone, and on the sweet spot.^2,14 These experiences have also been extensively documented as a cornerstone of various spiritual disciplines.^15,16

Many writers and philosophers have suggested that the control of attention and its resultant mental state facilitates intellectual ability. William James stated in 1890¹⁵ that “the faculty of voluntarily bringing back a wandering attention, over and over again, is the very root of judgment, character, and will . . . . An education which should improve this faculty would be the education par excellence.” Learning how to be fully engaged in a task is a fundamental challenge of human cognition. However, we must also have the flexibility to disengage at appropriate times. Extreme inattention to dangerous cues is certainly maladaptive. The rewards and punishments associated with task engagement through the course of human development are inconsistent, and the ability to control the level of absorption in a task is thus one of the cardinal mechanisms of successful human brain function. The importance of the concept of self is quite evident in this mechanism, as the more successful the process of switching between external stimuli and internal mental machinations, the more a person feels as though he or she is the master of his or her own cognitive destiny.

One of the fundamental benefits that are derived from the control of cognitive engagement is a more rewarding interpersonal experience. Martin Buber¹⁶ described the “I-You” experience as being the pinnacle of social-spiritual relationship in which the engagement between two persons becomes so completely absorbing that the boundary between the two is no longer experienced. The engrossment and satisfaction with complete absorption in another person is described as rewarding—satisfying and meaningful in itself. The importance of this mechanism for human survival is clear, as it enhances social experiences from sexual relations to community service to teamwork.

Human disciplines that increase engagement, such as meditation, have been found to reduce activation of the frontal cortex and anterior cingulate.¹⁷ These data are also supported by similar frontal reductions in subjects who engage in ‘watchful waiting'—the period of time in which subjects are listening for something they can barely hear or watching for something they can barely see. Presumably, the process by which subjects clear their minds of any conscious content so that they will perceive the information they are about to receive is associated with a decrease in activation of the prefrontal cortex. Planning, internal machinations, concern for context, and other complicated human cognitive functions are suspended in time while subjects wait for the perceptual stimulus. Cortical activation is shifted toward the systems that might experience the stimulus that does not yet exist. Subjects are engaged in the present moment with no stimuli yet forthcoming. The benefit of these disciplines is that enhanced engagement in real stimuli becomes easy by comparison.

It is likely that successful task engagement is determined in part by genetic and pharmacologic mechanisms. For instance, increased prefrontal dopamine signaling regulated by the COMT genotype^18,19 has an impact on information updating and is reflected in demands for continuous selection and deselection of information independent of working memory load or delay. Pharmacogenetic approaches for improving cognition²⁰ may thus benefit from a focus on the enhancement of task engagement.

Disengagement in Schizophrenia

Given the rewarding and adaptive nature of cognitive engagement for human beings, its failure has serious consequences. Many of these consequences can be seen in patients diagnosed with schizophrenia. One of the most striking features of schizophrenia is the severe inability to engage in the tasks that bring reward to every day life. As evidenced by the high rate of unemployment, low rate of marriage, cognitive performance deficits, and social performance difficulties, patients with schizophrenia have great difficulty engaging in cognitive tasks,¹³ social interactions,²¹ occupational activities, and intimate relations. The fundamental human activities of love, work, and play require task engagement. People with schizophrenia suffer in all of these areas as a result of their tendency to disengage during these crucial aspects of life.

For frontal activation to be reduced, an individual must learn a task sufficiently to allow more posterior systems to regulate behavior. Athletes or artists can never attain the experience of smooth, effortless perfection if they never practice their craft. In someone with schizophrenia, an inability to engage with a task may limit learning and thus limit the ability to reach the automatic stages of processing. Patients with schizophrenia have been found to disengage from tasks at a much lower level of difficulty compared to healthy controls.¹³ Further, when performing cognitive tasks on the same level of performance and difficulty as healthy controls, they have been found to have excessive “inefficient” frontal activation.¹² In this manner, increased frontal functioning may reflect the inability of schizophrenia patients to learn a task well enough to allow the shift toward the regulation of behavior by more posterior regions. This shift, as described above, is normally described as rewarding. Thus an absence of this shift in people with schizophrenia may further reduce the incentives to engage in tasks sufficiently enough to learn them. Moreover, since rewards have been found to be determined more by the expectation of reaching a goal rather than goal attainment itself, a reduced expectation for goal attainment in patients with schizophrenia may further reduce incentives. Thus, limitations in engagement, learning, and expectations for success found in many patients with schizophrenia converge to create great difficulty for everyday challenges, such as employment and social relationships, and reduce the rewarding nature of these activities.

It is possible that this disengagement precedes the onset of psychosis. Individuals who eventually develop schizophrenia demonstrate a significant decline in cognitive ability⁴ and scholastic aptitude³ in late adolescence. Since the prefrontal cortex is the last neuroanatomical structure to develop in humans, continuing into young adulthood,²² and since the onset of schizophrenia often occurs during this time, it is possible that psychosis develops as a function of a reduced ability to engage in the various complex tasks associated with developing into a functional adult. The manifestation of cognitive disengagement and interpersonal disengagement is often viewed as lack of motivation, particularly in adolescents, who may reduce the amount of visible effort applied to activities, such as school and social functioning. While laboratory data suggest that patients with schizophrenia are able to engage with easy cognitive tasks as evidenced by normal pupillary dilation, when task difficulty increases, schizophrenia patients do not demonstrate the same increase in pupillary dilation found in healthy controls; in fact, they may demonstrate constriction¹³ consistent with task disengagement. It will be important to determine at what point in the development of psychosis that this disengagement emerges. It may be that the complexity of tasks in adolescence increases with time, but that individuals who later develop schizophrenia are not able to advance their levels of engagement to meet these new challenges.

The social and psychological consequences of task engagement may be profound, especially during adolescence, when the development of the frontal cortex is paralleled by an emerging sense of a coherent self-identity. Humans are generally greatly rewarded by successful engagement in social interaction, which requires a frequent shift from egocentric to allocentric perspectives. However, if the complexity of this task becomes too demanding, and the engagement with others less rewarding, a tendency to remain submerged in internally generated mental events may result.²³ This loss of self may increase the vulnerability to psychosis. It is unlikely that this process is directly related to a single, or even to a small number, of neural or genetic mechanisms. It is likely that the conversion to psychosis is determined by a series of potential complex genetic vulnerabilities that manifest themselves as a growing brain interacts with an increasingly complex society in which the opportunities for social failure have become ubiquitous.

Perhaps one of the most devastating consequences of reduced engagement is the inability of patients with schizophrenia to engage in the type of therapeutic alliance that benefits other patients in medical and psychiatric settings. It has been clearly established that patients with schizophrenia who adhere to medication regimens are less likely to relapse. Furthermore, patients motivated in a productive therapeutic alliance are more likely to adhere to treatment regimens.²⁴ Cognitive impairment is likely to have a substantial role in a patient's ability to engage in a therapeutic alliance and to adhere to prescribed treatments.²⁵ It is possible that cognitive improvement may increase treatment effectiveness.²⁶

Future Directions

If, as outlined in this article, impairment in the cognitive and social engagement enjoyed by most people is a core feature of schizophrenia, treatments that focus on enhanced engagement should be encouraged. National Institute of Health programs, such as the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) and Treatment Units for Research on Neurocognition in Schizophrenia (TURNS) projects, and pharmaceutical company developmental programs are increasingly emphasizing this area of work. In addition, although far less financial resources have been directed to behavioral interventions for improving cognitive and social engagement, the potential value of these treatments is enormous. Recent studies suggest that schizophrenia patients may benefit from computer games with engaging stimuli,²⁷ and that cognitive-behavioral strategies may reduce the conversion to psychosis in high-risk individuals.²⁸