¹Peking University, Beijing, Beijing, China

Background: Patients with chronic schizophrenia present difficulties in humor recognition and appreciation, but the clinical features and neural mechanism of humor processing in the early stage of illness remains unclear.

Aims & Objectives: This study aimed to elucidate clinical features and neural substrates underlying humor processing in patients with first episode schizophrenia (FES).

Method: This study recruited 45 patients with FES and 44 matched healthy controls. Participants completed the Picture Humor Processing Task (HPT-p) and the Video Humor Processing Task (HPT-v) which tapped into humor comprehension and appreciation. 40 of the patients and 31 of the controls completed a fMRI verbal humor processing paradigm comprising 96 stories, half for funny punch-line condition and the other half for unfunny condition. Signal detection theory (SDT) analysis was used to calculate d’ and β values which represented sensitivity and inner criteria for humor signals respectively. The funny-unfunny contrast was analyzed to identify the brain regions related with humor processing. d’ and β values were put into the imaging regression analysis.

Results: In HPT-p, patients with FES showed higher false alarm rate (p = 0.048) while comparable sensitivity of humor signals (d' value) and intrinsic evaluation criterion (β value) compared to healthy controls. In HPT-v, patients with FES showed lower within-group coherence in funniness rating (p = 0.023). In verbal humor processing, patients with FES showed significantly lower sensitivity (d' value). At the neural level, patients with FES hypo-activated in ventral medial prefrontal cortex (vmPFC) and anterior cingulate cortex (ACC) while hyper-activated in middle temporal gyrus (MTG) and superior temporal gyrus (STG) compared to controls. In addition, activity in vmPFC and ACC was positively associated with d’ and β values, while activity in STG was positively associated with β values in the clinical group.

Discussion & Conclusions: Patients with FES exhibited decreased sensitivity to humor signals and made more misjudgment, indicating impairment of humor recognition. However, they showed intact humor appreciation. At the neural level, hypo-activation in frontal regions and hyper-activation in temporal regions were associated with the humor processing deficits in FES.