Characterizing human spontaneous thoughts and its application in major depressive disorder

Area of Science:

• Cognitive Psychology
• Neuroscience
• Psychiatry

Background:

• Spontaneous thought is a fundamental cognitive process with significant implications for mental well-being.
• Disruptions in spontaneous thought patterns are strongly associated with various mental disorders, including depression.

Purpose of the Study:

• To investigate the characteristics of spontaneous thought content in individuals with depression compared to healthy controls.
• To explore sex-based differences in spontaneous thought content among healthy individuals.
• To evaluate the utility of the think-aloud method and natural language processing (NLP) for analyzing thought content in depression.

Main Methods:

• The think-aloud method was employed to collect spontaneous thoughts during rest from participants with depression and healthy controls.
• A comprehensive assessment of thought content dimensions was conducted.
• Natural language processing (NLP) was utilized to develop regression and classification models for content analysis and depression differentiation.

Main Results:

• Individuals with depression displayed more internally oriented, self-focused, and negative spontaneous thoughts than healthy controls.
• Healthy women, compared to men, showed greater focus on interoception, the self, past, and negative events, with heightened negative emotions.
• NLP models demonstrated potential for multidimensional content assessment and depression classification.

Conclusions:

• This study provides direct insights into resting-state spontaneous thought content, identifying key differences between individuals with depression and healthy controls, as well as sex-specific variations.
• The findings enhance the understanding of spontaneous thought processes in depression.
• This research offers novel perspectives for the prevention, diagnosis, and treatment of depression.