THE GENERAL HEALTH QUESTIONNAIRE - HOW MANY ITEMS ARE REALLY NECESSARY IN POPULATION SURVEYS

This paper seeks to investigate whether only a few questions selected from the General Health Questionnaire (GHQ) may be used to measure the degree of mental distress in population surveys. Data from 2112 men a nd women, 18 to 70 years old from two cross-sectional studies conducte d in northern Norway and the island of Spitzbergen in the Arctic, were used. Correlation analysis of Likert scores from a 20-item version of GHQ (GHQ-20) with Likert scores based on four and six items selected by multiple regression analysis or by competent physicians was perform ed. The correlation coefficients between the scores from the subsets o f four items and the full GHQ-20 questionnaire were high (greater than 0.80) in all examined subgroups of the populations. Increasing the nu mber of questions from four to six only marginally increased the corre lation coefficients. Thus, a simple linear sum of Likert scores based on a few GHQ items can be used to measure the degree of mental distres s in population surveys.