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Case Study: Sam, a 44-Year-Old Male with Depression

While all case studies are based on actual patients, significant aspects of the case have been changed to conceal the patient’s original identity.

Initial Presentation

Sam was a lawyer on disability due to chronic, medication-resistant depression. After trying over a dozen different medications and multiple rounds of transcranial magnetic stimulation, Sam was still struggling with overwhelming symptoms. When I finally met him, his depression had overwhelmed his capacity to work. His time was filled with visits to therapists, counselors and physicians. While his career had been promising, it was rapidly being curtailed by the severity of his depressive symptoms.

Initial Relevant Labs

  • 25-hydroxy vitamin D low at 19 ng/mL
  • Serum vitamin B12 low at 206 pg/mL
  • Ferritin was low at 13 ng/mL
  • Complete blood count and red blood cell indices were borderline for microcytic anemia

Based on the initial results, Sam was asked about his food intake. He described following a paleo diet, focusing on non-starchy vegetables, red meat and chicken. However, he had a weakness for buttered crescents and whole wheat toast, which often formed part of his breakfast. Due to having low iron with regular meat consumption, malabsorption was suspected and a celiac panel was added to the initial round of testing:

  • Tissue transglutaminase (tTG) antibody was positive
  • Endomysial antibody was positive

Working Diagnosis:

  • Major depression secondary to celiac disease

Initial Treatment

  • Vitamin D, 5000 iu
  • B12 injections, 1 mg weekly
  • Iron bisglycinate 20 mg three times daily
  • Multivitamin
  • Gluten-free diet


In a male who consumes meat on a regular basis, iron deficiency is uncommon. The main causes are blood loss and problems with nutrient absorption. Celiac disease is a potential cause of iron deficiency in men (Montoro-Huguet 2021). While Sam did not have any gastrointestinal (GI) symptoms, a significant subset of celiac patients do not present with GI complaints (Green 2005).

Even without obvious GI symptoms, celiac disease can cause or contribute to depression (Sharma 2021), likely from increased inflammation and nutrient deficits caused by poor absorption. While Sam’s low iron and B12 were treated more directly, a multivitamin was also added to make sure other underlying nutritional needs were met.

Follow-up Presentation

Sam’s recovery was slow, but consistent with the implementation of a gluten-free diet. After three months, his depression symptoms were improved enough that he was able to restart work. Testing also confirmed that the nutritional deficiencies had been restored back into the normal range. The B12 injections and iron were stopped and Sam continued with just vitamin D and a multivitamin.

Case Summary

Celiac disease is an often-overlooked cause or contributing factor to a variety of different mental health conditions (Alkhiari 2023). While it is a more obvious rule out when patients have classic gastrointestinal symptoms, celiac disease should still be a consideration in other mental health conditions, especially when significant nutritional deficiencies are present.

Treatment of celiac disease is fairly straightforward through the implementation of a gluten-free diet, although some patients struggle to fully eliminate gluten. Recovery is variable and often slow. One study found that only 65% of people with celiac disease on a gluten-free diet had achieved histologic remission by two years (Wahab 2002). While unnecessary in Sam’s case, some patients need additional support to help heal the gastrointestinal tract and improve recovery.

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Alkhiari R. Psychiatric and Neurological Manifestations of Celiac Disease in Adults. Cureus. 2023;15(3):e35712. Published 2023 Mar 3. doi:10.7759/cureus.35712

Montoro-Huguet MA, Santolaria-Piedrafita S, Cañamares-Orbis P, García-Erce JA. Iron Deficiency in Celiac Disease: Prevalence, Health Impact, and Clinical Management. Nutrients. 2021;13(10):3437. Published 2021 Sep 28. doi:10.3390/nu13103437

Sharma N, Singh K, Senapati S. Celiac disease poses significant risk in developing depression, anxiety, headache, epilepsy, panic disorder, dysthymia: A meta-analysis. Indian J Gastroenterol. 2021;40(5):453-462. doi:10.1007/s12664-021-01215-2

Wahab PJ, Meijer JW, Mulder CJ. Histologic follow-up of people with celiac disease on a gluten-free diet: slow and incomplete recovery. Am J Clin Pathol. 2002;118(3):459-463. doi:10.1309/EVXT-851X-WHLC-RLX9