SPSD - A new rating scale for psychological distress in adolescence: a validation study on a nationwide Italian cohort of 31,661 adolescents

In this paper we present a new rating scale for adolescent psychological distress based on an Italian population study carried out in a cohort of 31,661 adolescents, and analyzed with Rasch Analysis in addition to the traditional tests. The Italian epidemiological survey on drug use in the school population was conducted by the Department of Anti Drug Policies in the first six months of 2014. It was based on a methodology of the European Monitoring Centre for Drugs and the Drug Addiction (EMCDDA - European School Survey Project on Alcohol and Other Drugs - ESPAD). The questionnaire and the survey procedures were taken from ESPAD and adjusted modified in order to address the specific characteristics of to the Italian school system. The total population sample consisted on 31,661 15-19 years old students who attended Italian public high schools. Among the items in the source scale we have selected nine items belonging to three dominions (Energy, Emotional Stability, Impulsivity and Risk-Taking) from which we expected the maximal indirect relation to wellbeing state and therefore as complement, to distress. To evaluate the psychometric properties of distress scale we carried out the homogeneity analysis or internal consistency of the scale, using the Cronbach's alpha coefficient, and analysis of the validity of the scale, using the Gamma coefficient of Goodman and Kruskal - index rank correlation. The data dimensionality was explored using Rasch Analysis and factor analysis. The Cronbach's alpha obtained considering all items was to 0.694, making it quite satisfactory and meeting the standards criteria of acceptability. Rasch analysis confirmed the items validity and that the items distribution remains in the area of the tolerance defined. A very good distribution emerges with a complete absorption of possible values along the scale range; neither ceiling or floor effect is observed. Whereas the level of distress measured by the scale is higher the lower the score detected, it is observed a significantly higher level of distress in females than in males (52.59 vs 59.61). For all psychotropic substances analyzed,significantly higher levels of distress in consumers than non-consumers have been found. In addition,the level of distress as measured by the scale appears to increase going from users of “soft” drugs to users of “hard” drugs: - 57.18 is the mean value obtained in the distress scale from the group of students who say they have never used any illegal drug; - 53.00 is the mean value obtained in the distress scale from the group of students who report use of cannabis at least once in their life; - 50.18 is the mean value obtained in the distress scale from the group of students who report use of cocaine at least once in their life; - 47.95 is the mean value obtained in the distress scale from the group of students who report use of heroin at least once in their life. This survey has detected several factors/conditions associated to the use of substances, which can be considered a reliable proxy of psychological distress: family background seems to be very important as well as the relationship with parents; this emerged as regards the presence of rules on behavior outside the home, the quality of relationships with prominent adult figures (particularly the father), their leadership role, and the family harmony.