Objective – The General Health Questionnaire is a self-rating scale, firstly for screening non-psychotic psychiatric disorders, and secondly, to measure general psychological distress. The paper presents discriminatory parameters of the Polish version of the GHQ-30 questionnaire.
Subjects – The study was carried out on a group of 104 patients (39 males and 65 females, mean age 41.4 years) attending either psychiatric outpatient clinics or primary health care outpatient facilities due to anxiety and depression symptoms.
Method – They were diagnosed using a diagnostic questionnaire based on the Schedule for Clinical Assessment in Neuropsychiatry (SCAN 2.0). GHQ scores were calculated using the [0, 0, l, 1] method. The receiver operating curve (ROC) was used to determine theoptimal values of discriminatory parameters.
Results – The best cut-off point was found to be the score 12/13, with sensitivity 82%, and specificity 80%. The positive and negative predictive values were 82% and 88%, respectively for the real prevalence of 64%. Adjusting the results so as to truly reflect the lower case-prevalence rate in the general population (prevalence rate = 10%), the predictive values of 31% and 98% were obtained.
Conclusions – Such discriminatory parameters are quite satisfactory, allowing to use the GHQ-30 as a screening tool to identify people with psychological problems in the general population. Moreover, the GHQ-30 can be a useful measure of general psychological distress.