Purpose of Review <p>To assess evidence supporting a relationship between internet gaming disorder and gaming disorder, both referred to as pathological gaming (PG) and hikikomori.</p> Recent Findings <p>We employed a systematic search strategy and identified 24 original articles comprising three reviews, six case studies, 13 cross-sectional studies and two longitudinal studies. Case studies and cross-sectional studies suggested a positive correlation between symptoms of PG and hikikomori; but, longitudinal findings do not support a robust prospective relationship.</p> Summary <p>Overall, studies indicating a positive correlation between the two conditions suffer from methodological limitations and substantial risk of bias – such as data primarily coming from non-clinical samples, analyses restricted to cross-sectional data, and a lack of consideration of confounding factors. We discuss conceptualizations of PG and hikikomori to clarify similarities (physical isolation to some degree and reduced social relationships, school refusal/dropout, loss of interest in other activities, and impact on daily life) and differences (dysfunction in self-regulation and impaired control over gaming in PG; pathological level of social refusal, avoidance, or disinterest yielding an unwillingness to attend school/work and to participate in social interactions in hikikomori) between the two conditions and improve the understanding of potential comorbidity and symptom overlaps. Associations of small-to-moderate magnitude and conceptual analysis point to PG and hikikomori being different conditions. Future studies need to investigate shared risk factors and potential confounders (e.g., parent-child relationship quality, poor social and problem-solving skills, avoidant personality traits, traumatic events, and symptoms of mood and anxiety disorders) to control for the risk of spurious association and uncover the nature of the association between PG and hikikomori, if any.</p>