Problematic smartphone use (PSU) is an increasing global concern, particularly among young people, and emotional factors can play a crucial role in PSU. This study investigated the relationships between loneliness, body attitudes, PSU, and smartphone deprivation (withdrawal) feelings using a structural equation modeling (SEM) approach. A total of 697 Hungarian participants (74.8% female, Mage = 23.51 ± 7.26) completed the Smartphone Application-Based Addiction Scale, the Loneliness Scale, the Body Attitude Test, the Smartphone Withdrawal Symptom Scale, and demographic questions. The results revealed that loneliness was positively related to PSU and smartphone deprivation, with body attitude mediating these relationships. Age was a protective factor since older individuals reported less PSU and feelings of deprivation. While an alternative non-mediated model yielded a comparable fit, the mediated model provided a more thorough perspective. Overall, the findings suggest a potentially vicious cycle in which loneliness, negative body attitude, and PSU reinforce one another, with feelings of smartphone deprivation further exacerbating PSU. This cycle not only deepens psychological distress but also underscores the urgent need for targeted interventions to enhance body image and social well-being as a means of mitigating PSU. Given the broader implications, further empirical research, particularly cross-cultural validation, is essential to ensure the findings apply across diverse populations and inform globally relevant strategies.