Investigating the dimensional diagnosis of ICD-11 nicotine dependence.

We investigated the dimensionality and possible measurement bias of ICD-11 Nicotine Dependence (ND) criteria in a sample of smokers from a middle-income country. Data are from the São Paulo Megacity Project (part of World Mental Health Surveys) collected between 2005 and 2007 (n = 5,037). The current analyses were restricted to the 1,388 participants who smoked at least once a week for 2 months in their lifetime. Item response theory (IRT) was used to investigate the severity and discrimination properties of 8 selected criteria. Additionally, differential criteria functioning (DCF) with sociodemographic characteristics (income, gender, age, employment status, marital status, and education) was investigated. All analyses were performed in Mplus software taking into account complex survey design features. IRT results indicated that the criterion Given Up had the lowest probability of endorsement (highest severity). The criterion Larger/Longer had the highest probability of endorsement (lowest severity), but the highest value of discrimination. Physical Withdrawal had the lowest discrimination property. No DCF was found both at criterion- and disorder-level, which would tear measurement bias. The absence of measurement bias in all sociodemographic, psychiatric, and medical subgroups gives psychometrical support to this set of criteria for ICD-11 ND diagnosis. (PsycINFO Database Record