The Strengths and Difficulties Questionnaire Self-Report Version for Adults: Psychometric Properties and Norms in an Italian Community Sample

The Strengths and Difficulties Questionnaire (SDQ) is a widely used screening instrument for assessing emotional symptoms, conduct problems, hyperactivity/inattention, peer problems, and prosocial behavior. Originally developed for use in children and adolescents, a self-report version for adults has recently been introduced; however, studies assessing its psychometric properties in community adult samples remain limited. This study aimed to address this gap by examining the psychometric properties of the SDQ in a sample of 982 Italian adults aged 19 to 55 years. We investigated the internal structure of the SDQ, its convergent and discriminant validity, and provided normative data. Confirmatory factor analysis supported a six-factor model based on prior research, combining the original five SDQ scales with a positive construal method factor composed of positively worded items from the four difficulties scales. Most SDQ scales showed appropriate ordinal alphas, although the peer problems and conduct problems scales demonstrated lower reliability, consistent with previous findings. Measurement invariance across sex was confirmed, and females reported higher emotional symptoms than males. Norms were provided for the five SDQ scales, both for the total sample and separately by sex. The SDQ showed a pattern of associations with anxiety, depression, stress, impulsivity, and self-control, largely in line with conceptual expectations, even when controlling for social desirability. These findings suggest that the Italian version of the SDQ is a suitable screening instrument for use in community adult populations.