Cognitive Impairment and Perceived Stress in Schizophrenic Inpatients with Post-Traumatic Stress Disorder

Abstract

The rate of lifetime traumas in the general population is high and a great deal of evidence suggests that persons with severe mental illness (SMI) show an even higher degree of vulnerability to trauma throughout their lives. Recent studies report between 13 and 29% of comorbid Post-Traumatic Stress Disorder (PTSD) in schizophrenic patients. Other studies showed that SMI patients with PTSD were in poorer health, had lower self-esteem, and had lower subjective quality of life and more cognitive deficits in comparison with those without PTSD. The aim of this work is to study a sample of chronic schizophrenic inpatients admitted after the L'Aquila earthquake, to assess if comorbid PTSD is associated with a higher rate of neurocognitive deficit and poorer quality of life in comparison with schizophrenic inpatients without PTSD. The sample of this study, recruited after the L'Aquila earthquake (between April 2009 and December 2009), consisted of 54 schizophrenic earthquake survivors admitted consecutively to the Psychiatric Inpatients Unit of L'Aquila San Salvatore Hospital. Each patient was assessed with the Positive and Negative Syndrome Scale (PANSS) and the General Health Questionnaire − 12 items (GHQ-12). The Impact of Event Scale-Revised (IES-R) was used to grade post-traumatic symptoms. PTSD diagnosis was made with the Structural Clinical Interview for DSM-IV (SCID-I). The cognitive assessment battery included WAIS-III Digit Span and Trail Making Test to assess working memory and executive functions, respectively. The severity of illness was measured with the Clinical Global Impression Scale (CGI). All the patients were on antipsychotic drugs at a mean daily chlorpromazine-equivalent dose of 236.38 mg (SD 183.5). 17% of the 54 schizophrenic inpatients (n 9) met the DSM-IV criteria for PTSD. PTSD subjects had significantly higher scores on the PANSS Positive Symptom subscale (P ≤ 0.015) and higher GHQ-12 mean score (30.50 vs 16.93). In the presence of post-traumatic symptoms a significant difference between the two groups (with and without PTSD) was found in hyper-arousal subscale scores, with a significant impairment of working memory in the PTSD sample. PTSD symptom measures positively correlated with the PANSS total and Positive score and GHQ-12 score > 20 (“high stress level”). PTSD in schizophrenic patients is associated with a more severe cognitive deficit, higher levels of perceived stress and more positive symptoms. The investigation of PTSD in patients with schizophrenia might have important implications for their clinical management and for future research.