A multitude of studies have examined the link between sleep bruxism (SB) and psychological distress, producing heterogeneous outcomes. Distinct diagnostic criteria have been applied to identify SB. The purpose of this investigation was to compare the relationship between psychological distress and SB as classified by different validated approaches. Data from 45 participants were analyzed, including group-based comparisons and correlational analyses. The following diagnostic modalities for detecting SB were employed within a single cohort: self-report, clinical evaluation, polysomnography complemented by audio–video recording, and an innovative diagnostic foil with dedicated analysis software. Psychological distress was quantified using the Global Severity Index (GSI) from the Symptom Checklist-90-Standard (SCL-90-S). Scores on the GSI did not significantly distinguish subjects with and without SB, independent of the diagnostic framework applied (P > 0.05). More detailed correlational analyses of self-report and clinical findings indicated a weak-to-moderate association with the GSI (r = 0.12–0.44). Owing to the non-normal distribution of the data, formal statistical significance testing was not feasible. Indicators derived from instrumental techniques, exemplified by the SB index (SB activity events per hour) from polysomnography (PSG), displayed virtually no relationship with psychological distress (r = −0.06–0.05). Acknowledging the study’s constraints, the data imply that variation in the selected diagnostic protocol might account for discrepancies in the observed correlation between SB and psychological distress.
