Schizophrenia is a psychotic disorder characterized by a lack of ability to stay in touch with reality. This means people with schizophrenia may often experience episodes of thoughts and behaviours that are not realistic.
Delusions are one such unrealistic symptom of schizophrenia. Even when confronted with evidence to the contrary, the person maintains delusions, which are beliefs or an altered reality. The Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) categorizes many forms of delusions in schizophrenia.
A team of researchers from the Hertie Institute for Clinical Brain Research at Tubingen University Hospitals conducted a study to analyze specific type of delusions called ‘delusion of control’.
Delusion of control is a phenomenon where the person feels that external forces are controlling them, which in turn impacts their thoughts and actions. For example, a person with such symptoms may feel that black magic or aliens are causing their headaches and hence refuse to get it checked by a doctor.
Based on research done by Manuel J. Roth et al., it was found that people who experience the delusion of control experience the time interval between their actions and their consequences differently than other people. The following sections describe this study in detail.
Obtaining evidence using the Bayesian causal inference models, the research explains the concept of intentional binding. According to Dr. Axel Linder, intentional binding is perception a of an observer about temporal proximity between the action and its consequences. To understand the feelings of authorship of actions, this concept of intentional binding is being applied.
Linder explains this concept using an example of the lamp. We may switch on the lamp by pressing the ‘on’ switch in the lamp. When you press the switch, the light comes on instantaneously, resulting in this close temporal sequence as an immediate outcome. When you press the switch, the light turns on instantaneously, resulting in this close temporal sequence as an immediate effect.
But this may not always be the case. According to Linder’s explanation about the unique phenomenon of brain perception in energy-saving lamps, the consequence occurs after a time delay from the action. Thus, the brain subjectively alters the perception in this situation. We perceive turning on the switch as later and lighting up as earlier. This perceptual mechanism was not present in people who had delusions of control.
Upon collaborating with Professor Marc Buehner from Cardiff University, the research team recruited 40 participants for the study. Out of 40, 20 were healthy participants, 10 were schizophrenic patients without delusion of control symptom and other 10 schizophrenic patients suffered from the symptom of delusion of control.
We demonstrated three distinct experimental settings. In one case, the subject used their left hand to press the lamp switch and turn on the lamp. In the second condition, the lamp was turned on by a machine and the participants had to just observe. In the third condition, a previous cue stimulus announced the lighting of the lamp.
All the participants had one task. This task was to press the button with the right hand when they saw a lamp light up. The lamp had a fixed switch-on delay of exactly half a second in all three conditions. In addition, the three triggers and lighting of the lamp were always the same length.
Findings of the Study
The study examined the phenomenon of intentional binding by using the above-mentioned experimental setup. It reported that there was no difference in perception between healthy controls and patients with schizophrenia who didn’t possess symptoms of delusions of control.
That is, these participants reported that the light came on earlier than it happened. In addition, they also perceived the duration of lamp lighting to be shorter in the second and third conditions, whereas, in the first condition, they perceived it to be longer.
On the other hand, the mechanism of intentional binding didn’t influence the perception of patients with delusions. Though the intentional binding was weaker, their perception of external force was greater. That is, they perceived the time interval to be the same in all three conditions. But they also reported that an external force such as a computer was turning on the light when they had to operate the switch themselves.
Although the study reports interesting findings there are limitations. This study underscores the significance of intact perception of temporal proximity in feelings of control over actions. In addition, this research consists of a small sample of participants posing questions to generalizability.
Improving Self-Action and Acceptance
Despite its limitations, the concepts of this study can be useful in future to assess this disorder and the likelihood of the occurrence of such symptoms. According to a publication in the current issue of PNAS, this research is important because it helps to predict the likelihood of such delusions, thereby increasing our understanding of schizophrenia.
It also explains how concepts such as personal responsibility are a huge part of our self and social lives including the administration of justice. In addition, it also provides important ideas on how to improve self-action and help improve acceptance of this disorder. The study concludes by highlighting the importance of the diminished sense of agency among such patients.