The neuroscience of free will: implications for psychiatry

Are mental disorders related to disbelief in free will? A systematic review

BACKGROUND

The nature and existence of free will have been debated for centuries. Since some psychiatric disorders are known to interfere with one's ability to control their actions and thoughts (e.g., schizophrenia), the investigation of the psychiatric facet of free will beliefs seems to be relevant. In this systematic review, we were interested in clarifying if and how having a mental disorder affects individuals' beliefs in free will by comparing psychiatric vs. non-psychiatric samples.

METHODS

A systematic search of MEDLINE, Web of Science, EMBASE, and PsycINFO databases was performed between 04 and 09 November 2020. The search strategy included "free will" and related constructs and terms related to DSM-5 mental disorders characterized by psychotic, compulsive, avoidant, or impulsive symptoms. Eligible designs of studies included case-control and cohort studies. Study selection took place in committee meetings consisting of six researchers. Quality assessment of the selected studies was performed through the Joanna Briggs Institute Appraisal Checklist for Case Control Studies.

RESULTS

After removing duplicates, a total of 12,218 titles/abstracts were screened. Inclusion and exclusion criteria were followed, and three articles were eventually selected.

CONCLUSIONS

It is not possible to provide unequivocal confirmation that having a mental disorder can or cannot affect someone's belief in free will. Studies with different mental disorders should be conducted in this field.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018109468.

New measures of agency from an adaptive sensorimotor task

Self-agency, the sense that one is the author or owner of one’s behaviors, is impaired in multiple psychological and neurological disorders, including functional movement disorders, Parkinson’s Disease, alien hand syndrome, schizophrenia, and dystonia. Existing assessments of self-agency, many of which focus on agency of movement, can be prohibitively time-consuming and often yield ambiguous results. Here, we introduce a short online motion tracking task that quantifies movement agency through both first-order perceptual and second-order metacognitive judgments. The task assesses the degree to which a participant can distinguish between a motion stimulus whose trajectory is influenced by the participant’s cursor movements and a motion stimulus whose trajectory is random. We demonstrate the task’s reliability in healthy participants and discuss how its efficiency, reliability, and ease of online implementation make it a promising new tool for both diagnosing and understanding disorders of agency.

Effect of alcohol on the sense of agency in healthy humans

Even at low to moderate doses, ingestion of the widely used recreational drug alcohol (ethanol) can impact cognitive and emotional processing. Recent studies show that the sense of agency (SoA; ie, the subjective experience of voluntary control over actions) can be modulated by specific pharmacological manipulations. The SoA, as quantified by the intentional binding (IB) paradigm, is enhanced by direct or indirect dopaminergic agonists in patients with Parkinson's disease and by ketamine (an N-methyl-D-aspartate (NMDA) receptor antagonist) in healthy individuals. These findings implicate dopaminergic and glutamatergic neurotransmission in mechanisms underlying SoA. Alcohol has a complex set of actions, including disinhibition of dopaminergic neurotransmission and allosteric antagonism at NMDA receptors. Here, we tested the hypothesis that low to moderate doses of alcohol would enhance SoA, and impact impulsivity and subjective emotional state. We conducted two experiments in 59 healthy male and female social drinkers, who ingested either a placebo "vehicle," or one of two doses of ethanol: 0.4 and 0.6 g/kg. In both experiments, we observed increased SoA/IB at both doses of alcohol exposure, relative to the placebo condition. We found no correlation between the effects of alcohol on IB and on impulsivity or subjective emotional state. Our findings might have implications for social and legal responsibility related to alcohol use, particularly in states prior to overt intoxication. Further studies are necessary to investigate the effects of alcohol and other addictive substances on the SoA.

Schizophrenia and Criminal Responsibility: A Systematic Review

The significant progress of psychiatry in the 20th century provided a sophisticated theoretical framework to analyze the complex relationships between crime and mental illness. Schizophrenia has been traditionally associated with severe cognitive and affective deficits that heavily influence empathy, judgment capacities, but also control of impulsiveness. Although there is an association between psychotic disorders and absence or decrease of legal responsibility, their relationship is also determined by sociodemographic, developmental, and clinical factors. These disorders are associated not only with abolished criminal responsibility but also with diminished responsibility. We conduct a systematic literature review to examine the relation between schizophrenia and criminal responsibility. We have found that this clinical entity is often associated with diminished or abolished criminal liability. We discuss these findings, focusing on the specific deficits found in patients with schizophrenia and examining how this problem affects their behavior and eventually their accountability for their crimes.

Free will perceptions and psychiatric symptoms in patients diagnosed with schizophrenia

WHAT IS KNOWN ON THE SUBJECT?: Some research suggests that holding a free will perspective may offer mental health and physical health benefits. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: This study is the first to examine links between free will perceptions and psychiatric symptoms in patients diagnosed with schizophrenia. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Study results suggest that helping people with a diagnosis of schizophrenia to recognize situations where they do have some freedom of choice over their actions and emotional reactions (free will) may assist them in improving their experiences and better managing their symptoms.

ABSTRACT

Introduction Some research indicates that having a strong sense that one possesses free will may be associated with better psychological and physical health. This study is the first to examine the relationship between free will perceptions and psychiatric symptoms in patients with a diagnosis of schizophrenia. Method Thirty-two participants were interviewed using the Brief Psychiatric Rating Scale to assess symptom severity and the Free Will Subscale of the Free Will and Determinism Scale to assess free will perceptions. Results As hypothesized, a negative association was found between free will perceptions and total symptom severity, though it appears that this was mainly accounted for by positive symptoms. A content analysis was also conducted to qualitatively examine how patients conceptualize the construct of free will and its role in coping with their own mental illness. Discussion Study results suggest that holding a free will perspective may mitigate psychiatric symptoms in patients with a diagnosis of schizophrenia. Thus, psychiatric nurses and other mental health clinicians may improve current treatments for schizophrenia by helping patients recognize situations where they do have some freedom of choice over their actions and emotional reactions (free will) to stressful life events.

Culturally sanctioned suicide: Euthanasia, seppuku, and terrorist martyrdom

Suicide is one of the greatest concerns in psychiatric practice, with considerable efforts devoted to prevention. The psychiatric view of suicide tends to equate it with depression or other forms of mental illness. However, some forms of suicide occur independently of mental illness and within a framework of cultural sanctioning such that they aren’t regarded as suicide at all. Despite persistent taboos against suicide, euthanasia and physician-assisted suicide in the context of terminal illness is increasingly accepted as a way to preserve autonomy and dignity in the West. Seppuku, the ancient samurai ritual of suicide by self-stabbing, was long considered an honorable act of self-resolve such that despite the removal of cultural sanctioning, the rate of suicide in Japan remains high with suicide masquerading as seppuku still carried out both there and abroad. Suicide as an act of murder and terrorism is a practice currently popular with Islamic militants who regard it as martyrdom in the context of war. The absence of mental illness and the presence of cultural sanctioning do not mean that suicide should not be prevented. Culturally sanctioned suicide must be understood in terms of the specific motivations that underlie the choice of death over life. Efforts to prevent culturally sanctioned suicide must focus on alternatives to achieve similar ends and must ultimately be implemented within cultures to remove the sanctioning of self-destructive acts.