Salud Mental 2017;

ISSN: 0185-3325

DOI: 10.17711/SM.0185-3325.2017.002

Received first version: August 19, 2016; second version: December 15, 2016; accepted: January 3, 2017.

Effect of substance use on condom use in the Theory of Planned Behavior: Analysis of differential item functioning

Ricardo Sánchez-Domínguez 1 ,2 , Luis Villalobos-Gallegos 1 , Violeta Felix-Romero 2 , Silvia Morales-Chainé 2 , Rodrigo Marín-Navarrete 1


1 Unidad de Ensayos Clínicos, Subdirección de Investigaciones Clínicas. Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz.

2 Facultad de Psicología, Universidad Nacional Autónoma de México.

Correspondence: Luis Villalobos-Gallegos. Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz (INPRFM), Unidad de Ensayos Clínicos en Adicciones y Salud Mental. Calz. México-Xochimilco 101, 14370 Ciudad de México. Phone: +52 (55) 4160-5482. E-mail: lvillalobos@imp.edu.mx


Abstract

Introduction. Substance use is one of the factors associated with lower condom use in young adults, which increases the likelihood of HIV infection. The Theory of Planned Behavior (TPB) is one of the most useful models for explaining this phenomenon since it considers the aim of engaging in a behavior based on attitudes, subjective norms and self-efficacy.

Objective. To develop a questionnaire and to evaluate the Differential Item Functioning (DIF) caused by substance use in TPB indicators, using the Multiple Indicators Multiple Causes Analysis (MIMIC).

Method. The study was conducted in two phases with Mexico City college students age 18 to 25.

Results. Adequate goodness of fit was obtained in all three models of the TPB: attitudes χ2 S-B(2) = 3.902, p < .001; CFIs = .999; TLIs = .996; RMSEAs = .037, 90% CI ≤ .001-.095; subjective norms χ2 S-B(7) = 9.103, p < 0.245; CFIs = .999; TLIs = .998; RMSEAs = .022, 90% CI ≤ .001-.056; and self-efficacy χ2 S-B(25) = 65.115, p < .001; CFIs = .982; TLIs = .974; RMSEAs = .050, 90% CI = .036-.066; in one item in attitudes and two items in subjective norms a DIF effect was observed, while no item proved significant regarding self-efficacy.

Discussion and conclusion. There is little evidence in the detection of DIF due to substance use in TPB indicators in condom use, and this is the first study to conduct this type of analysis. Items presenting DIF open the door to future research due to the importance of assessing how the indicator behaves with a population displaying a particular trai.

Key words: Condom, substance use, attitudes, self-efficacy, subjective norms, young adults.

Resumen

Introducción. El consumo de sustancias es uno de los factores asociados a un menor uso de condón en jóvenes adultos, lo cual aumenta la probabilidad de contagio de VIH. La Teoría de la Conducta Planeada (TCP) es uno de los modelos más útiles para explicar este fenómeno ya que considera la intención de llevar a cabo una conducta basándose en actitudes, normas subjetivas y autoeficacia.

Objetivo. Desarrollar un cuestionario y evaluar el Funcionamiento Diferencial de los Ítems (DIF) ocasionado por el consumo de sustancias en los indicadores de la TCP, utilizando el análisis Múltiples Ítems Múltiples Causas (MIMIC).

Método. El estudio se llevó a cabo en dos etapas con estudiantes universitarios de 18 a 25 años de la Ciudad de México.

Resultados. Se obtuvo una adecuada bondad de ajuste en los tres modelos de la TCP: actitudes χ2 S-B(2) = 3.902, p < .001; CFIs = .999; TLIs = .996; RMSEAs = .037, 90% IC ≤ .001-.095; normas subjetivas χ2 S-B(7) = 9.103; p < .245; CFIs = .999; TLIs = .998; RMSEAs = .022, 90% IC ≤ .001-.056; y autoeficacia χ2 S-B(25) = 65.115; p < .001; CFIs = .982; TLIs = .974; RMSEAs = .050, 90% IC = .036-.066; un ítem en actitudes y 2 ítems en normas subjetivas se observó un efecto DIF, y en autoeficacia ningún ítem salió significativo.