Chatbot Intervention Effects on Belief Updating in Anhedonia

Anhedonia represents a core characteristic of depression and is characterized by reduced experience of pleasure. It is closely related to decreased motivation, altered reward processing, changes in affective responsiveness, and alterations in intrinsic brain network function. Anhedonia is not specifically targeted by currently available pharmacological interventions. Initial evidence indicates that an increased willingness to change and implementation of change in daily life can alleviate anhedonia.

The present study aims to examine whether a Motivational Interviewing-based AI chatbot can lead to changes in belief updating in college students with elevated anhedonia and depressive symptoms. Belief updating is included because anhedonia and depressive symptoms may be associated with biased or inflexible use of new information, which may influence future expectations, motivation, and engagement in rewarding activities. The belief updating task allows the study to examine how participants revise their expectations after receiving new information. To this end, eligible participants with a total score of 22 or higher on the Snaith-Hamilton Pleasure Scale and a score of 14 or higher on the Beck Depression Inventory will undergo a randomized, between-subjects, active-control intervention study. Participants will be assigned to either a Motivational Interviewing-based chatbot group or an active control chatbot group for 1 week. Pre- and post-intervention assessments will include self-report questionnaires and a behavioral belief updating task to examine psychological and behavioral effects of the intervention.

Inclusion criteria

• 18-40 years
• Right-handed
• Normal or corrected normal visual acuity
• Participants must show elevated anhedonia and depressive symptoms at screening, defined as a total score of 22 or higher on the Snaith-Hamilton Pleasure Scale and a score of 14 or higher on the Beck Depression Inventory

Exclusion criteria

• History of major central nervous system disorders, such as epilepsy, traumatic brain injury, stroke, or brain tumors.
• History of severe mental illness, including schizophrenia spectrum disorders, bipolar disorder, or other psychotic disorders.
• History of substance or alcohol use disorder or substance or alcohol misuse within the past 12 months that may affect study participation or outcome assessment.
• Individuals currently at high risk of suicide, severe self-harm, or experiencing an acute psychiatric crisis.
• Individuals who are currently using psychiatric medications or have undergone psychotherapy within the past 4 weeks that may significantly affect mood, motivation, or reward processing.
• Severe vision or hearing impairments that cannot be corrected and would interfere with task performance.
• Contraindications to MRI scanning, including metallic implants, pacemakers, severe claustrophobia, or other conditions incompatible with MRI.
• Pregnancy or breastfeeding.