The COVID-19 pandemic and related control measures have increased the prevalence of anorexia nervosa (AN), and recent studies demonstrated that approximately 70% of individuals diagnosed with AN experienced deterioration in symptoms. This study aimed to examine the psychosocial and clinical impacts on patients with AN during the COVID-19 pandemic. This cross-sectional study involved 35 female AN adolescents who were being treated at Ege University Child and Adolescent Psychiatry Department. To assess pre-pandemic symptom levels and daily life routines, a retrospective form utilizing the visual analog scale (VAS) was employed. Body mass index (BMI) and Clinical Global Impression (CGI) data were recorded by an interviewer for all 35 patients who gave consent to participate in the study. Fifteen patients completed all the forms [VAS, the Children's Depression Inventory (CDI), the Screen for Child Anxiety Related Disorders Scale (SCARED), the Eating Attitudes Test, the Quality-of-Life Scale (QoLS), the Autism Spectrum Screening Questionnaire, and the Turgay DSM-4 Based Screening and Evaluation Scale for Behavioral Disorders in Children and Adolescents] online in 2022. Clinical diagnosis and progress were assessed retrospectively using The Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS). The duration of the follow-up period and the number of psychiatric visits were obtained retrospectively from patient files. Retrospective data on pre-pandemic symptom levels and daily life routines were collected using the VAS. The mean age of AN patients was 16.67 ± 1.63 years. Comorbid diseases were present in 73.33% of patients, and major depressive disorder (MDD) was the most common (46.66%). Mean scores indicated moderate levels of anxiety (SCARED score: 37.23 ± 12.67) and depression (CDI score: 17.23 ± 10.85). QoLS scores were negatively correlated with eating attitudes (r = −0.601, p = 0.039). Obsession level, exercise level, and screen time increased during the pandemic, while social activity, quality of education, and perception of learning decreased. BMI increased in all patients. Patients who completed the forms had a higher number of psychiatric visits compared to those who did not complete the forms (p = 0.033). The mean number of clinic visits was 26.27 ± 20.33. The results show that the COVID-19 pandemic had adverse effects on AN patients and disrupted their daily routines. These patients experienced high rates of comorbidities. The patients showed improvement in BMI scores, indicating the positive impact of treatment. These findings emphasize the need for comprehensive psychiatric care and targeted interventions for AN patients during crises such as the COVID-19 pandemic.