Over the last decade, researchers and engineers have developed a vast body of methodologies and technologies in requirements engineering for self-adaptive systems. Although existing studies have explored various aspects of this topic, few of them have categorized and summarized these areas of research in require-ments modeling and analysis. This study aims to investigate the research themes based on the utilized modeling methods and RE activities. We conduct a thematic study in the systematic literature review. The results are derived by synthesizing the extracted data with statistical methods. This paper provides an updated review of the research literature, enabling researchers and practitioners to better understand the research themes in these areas and identify research gaps which need to be further studied.