Response to Dell’Osso and Elli

To the Editor: We thank Drs. Dell’Osso and Elli for their critical interest in our article. They raise the issue of an “affective diathesis rather than schizophrenia” in the patient we reported on in our clinical case conference. They base their critique upon the patient’s history of depressive symptoms, hallucinations, and delusions as well as a family history of seasonal affective disorder in his parents and bouts of depression in his grandparents.

Depressive symptoms have been recognized as a feature of schizophrenia since Bleuler described them as either directly springing from the very process of the malady (i.e., primary symptoms) or as secondary symptoms of schizophrenia, stating that “chronic as well as acute depressions are found more frequently in the beginning of an outspoken illness than any other syndrome” (1). Kraepelin lists among the clinical forms of dementia praecox “simple depressive dementia” and “delusional depressive dementia” (2). In longitudinal population-based studies, the diagnosis of schizophrenia is often preceded by another diagnosis that is often affective in nature. In longitudinal studies, up to one-third of patients who initially had a diagnosis other than schizophrenia were later diagnosed with schizophrenia (3, 4).

Depressive symptoms in patients with schizophrenia can be observed during each phase of the disorder including the prodromal phase. It is important to note that in our case, depressive symptoms presented at age 15 in conjunction with psychotic symptoms in the context of his “first break” that caused the patient’s first hospitalization and a diagnosis of major depression with psychotic features. Depressive symptoms in the early course of schizophrenia have been associated with a family history of unipolar depression or psychiatric disorders other than schizophrenia (5, 6). A familial genetic liability to affective disorder, as in the case we have presented, can modify the patient's schizophrenic illness to increase expression of depressive symptoms.

Although there is some recent evidence linking major depressive disorder to celiac disease or gluten sensitivity (7, 8), the evidence does not have the long history and series of replications found in the literature on schizophrenia (9).We agree with the authors of the letter that celiac disease has been associated with psychiatric disorders other than schizophrenia, including major depressive disorder. With all this taken into account, we also agree with the authors that a gluten-free diet should be investigated in psychiatric disorders that show evidence of an association with celiac disease or gluten sensitivity.