Background/Objectives: Celiac disease is an immune-mediated enteropathy with heterogeneous gastrointestinal and extraintestinal manifestations. Psychiatric symptoms, arthralgia, thyroid comorbidity, anemia, and abnormal liver tests can obscure recognition in primary care. Methods: We report a de-identified reflective case from routine family medicine practice, structured in accordance with CARE case-report principles. Results: A woman in her early sixties with hypothyroidism and glaucoma presented with new low mood, anhedonia, somnolence, generalized anxiety, increased alcohol intake, poor appetite, weight loss, abdominal bloating, diarrhea, flatulence, and polyarthralgia. Investigations showed mild anemia, markedly elevated ferritin and liver enzymes, uncontrolled hypothyroidism, and strongly positive tissue transglutaminase IgA (>250 kIU/L; reference 0.0-14.9). Radiographs showed mild osteoarthritis and osteopenia without erosive arthropathy. CT abdomen/pelvis excluded malignancy but showed severe diffuse hepatic steatosis and mild pancreatic atrophy. The patient declined gastroenterology referral and confirmatory endoscopy with duodenal biopsy. A working diagnosis of probable celiac disease was made; she commenced a gluten-free diet, received alcohol-cessation advice, had levothyroxine adjusted, and was followed in the community. Most symptoms improved within six months. Conclusions: Celiac serology should be considered in adults with anxiety or depressive symptoms accompanied by gastrointestinal symptoms, weight loss, arthralgia, autoimmune thyroid disease, or unexplained liver-test abnormalities. The case also highlights diagnostic uncertainty, and follow-up needs when biopsy is declined.