Supplementary Material for: Do Psychosis Patients with Poor Insight Show Implicit Awareness on the Emotional Stroop Task?

Background: The insight into psychosis can be assessed reliably by clinicians from interviews with patients. However, patients may retain implicit awareness of illness while lacking explicit awareness. Sampling and Methods: In a sample of first-episode psychosis patients, we used a test of processing of mental illness-related and other negative words as a measure of implicit awareness to see how this varied in relation to insight. An emotional-counting Stroop task tested reaction times to words of three types: psychosis-related (e.g. ‘crazy'), general negative (e.g. ‘cancer') and neutral (e.g. ‘oyster'). Data were available from 43 patients and 23 healthy controls. Patients' insight was assessed using the Schedule for the Assessment of Insight (SAI-E). Results: Patients reacted slower than controls to words across all conditions, and both patients and controls reacted slower to salient and negative words than neutral words. There was a near significant interaction between word type and group (Wilks' lambda = 0.53, p = 0.055); patients experienced greater interference from negative rather than psychosis-related words (p = 0.003), and controls experienced greater interference from salient rather than negative words (p = 0.01). Within the patient group, there was a correlation between insight and interference on salient words (r = 0.33, p = 0.05), such that those with less insight experienced less interference on psychosis-related words. Conclusions: Psychosis-related words were less threatening and less self-relevant to psychosis patients with less insight. This suggests that the lack of awareness such patients have of their illness is genuine and more likely to be mediated by lower-level information processing mechanisms than strategies such as conscious, motivated denial.