Mixed-Effects Diffusion Models with General Drift R package mixediffusion version 1.0.0 Provides tools for likelihood-based inference in one-dimensional stochastic differential equations with mixed effects using expectation–maximization (EM) algorithms. The package supports Wiener and Ornstein–Uhlenbeck diffusion processes with user-specified drift functions, allowing flexible parametric forms including polynomial, exponential, and trigonometric structures. Estimation is performed via Markov chain Monte Carlo EM. Software Depends: R (>= 4.5) Imports: dplyr, adaptMCMC Suggests: testthat (>= 3.0.0) Pedro Abraham Montoya Calzada <pedroabraham.montoya@gmail.com> Comprehensive R Archive Network (CRAN) Pedro Abraham Montoya Calzada [aut, cre, cph] (ORCID: <https://orcid.org/0009-0002-3497-210X>), Rogelio Salinas Gutiérrez [aut, cph] (ORCID: <https://orcid.org/0000-0002-1669-4460>), Silvia Rodríguez-Narciso [aut, cph] (ORCID: <https://orcid.org/0000-0001-5429-5914>), Netzahualcóyotl Castañeda-Leyva [aut, cph] (ORCID: <https://orcid.org/0000-0001-9414-3923>) GPL-3 2026-03-20 application/tgz https://CRAN.R-project.org/package=mixediffusion doi:10.32614/CRAN.package.mixediffusion