ABSTRACT
BACKGROUND: Sexualized drug use (SDU) has become a public health concern in recent years. This study aimed to estimate the prevalence of SDU in gay, bisexual, and other men who have sex with men living with HIV (HIV + GBMSM) in Madrid during 2019/2020 and compare it with data from 2016/2017 in order to detect changes in patterns. METHODS: We analyzed the frequency of SDU in a sample of HIV + GBMSM attending HIV clinics, who participated in an anonymous online survey regarding sexual behavior and recreational drug use. The association between SDU, sexual risk behaviors, and STIs was evaluated. RESULTS: This study included 424 HIV + GBMSM, with a mean age of 40 (10.43) years. Overall, 94% (396) reported being sexually active. Additionally, 33% (140) had been diagnosed with an STI within the previous year. Moreover, 54% (229) had used drugs in the last year, 25% (107) engaged in SDU, and 16% (17) reported engagement in slamsex. After adjusting for confounding factors, SDU was associated with STIs, fisting, unprotected anal intercourse, and having >24 sexual partners in the last year. According to the DUDIT test scores, 80% (81) probably had problematic drug use (≥6 points), and 8% (8) probable drug dependence (≥25 points). When comparing the U-SEX-1 (2016/2017) data with the U-SEX-2 (2019/2020) data, no significant differences were found in the proportion of participants practicing SDU or slamming. CONCLUSIONS: The prevalence of SDU among HIV + GBMSM has remained high in recent years and without significant changes. The risk of problematic drug use among those who practice SDU is high. We observed a clear association between SDU, high-risk sexual behaviors, and STIs.
ABSTRACT
People show stable differences in the way their affect fluctuates over time. Within the general framework of dynamical systems, the damped linear oscillator (DLO) model has been proposed as a useful approach to study affect dynamics. The DLO model can be applied to repeated measures provided by a single individual, and the resulting parameters can capture relevant features of the person's affect dynamics. Focusing on negative affect, we provide an accessible interpretation of the DLO model parameters in terms of emotional lability, resilience, and vulnerability. We conducted a Monte Carlo study to test the DLO model performance under different empirically relevant conditions in terms of individual characteristics and sampling scheme. We used state-space models in continuous time. The results show that, under certain conditions, the DLO model is able to accurately and efficiently recover the parameters underlying the affective dynamics of a single individual. We discuss the results and the theoretical and practical implications of using this model, illustrate how to use it for studying psychological phenomena at the individual level, and provide specific recommendations on how to collect data for this purpose. We also provide a tutorial website and computer code in R to implement this approach. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
ABSTRACT
Latent Change Score models (LCS) are a popular tool for the study of dynamics in longitudinal research. They represent processes in which the short-term dynamics have direct and indirect consequences on the long-term behavior of the system. However, this dual interpretation of the model parameters is usually overlooked in the literature, and researchers often find it difficult to see the connection between parameters and specific patterns of change. The goal of this paper is to provide a comprehensive examination of the meaning and interpretation of the parameters in LCS models. Importantly, we focus on their relation to the shape of the trajectories and explain how different specifications of the LCS model involve particular assumptions about the mechanisms of change. On a supplementary website, we present an interactive Shiny App that allows users to explore different sets of parameter values and examine their effects on the predicted trajectories. We also include fully explained code to estimate some of the most relevant specifications of the LCS model with the R-packages lavaan and OpenMx.
