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12-03-2012 | Immunology | Article

Atopic disorders linked to increased schizophrenia risk


Free abstract

MedWire News: Results from a Danish study suggest that patients with atopic disorders, particularly those with asthma, are at increased risk for schizophrenia.

Writing in Schizophrenia Research, Michael Pedersen (Aarhus University) and team explain: "Autoimmune diseases and infections have been associated with an increased risk of schizophrenia that could be rooted in inflammatory mechanisms.

"However, other diseases characterized by a heightened immune response, such as atopic disorders, remain to be thoroughly investigated."

The researchers therefore used the Danish Psychiatric Central Register and the National Hospital Register to assess the risk for schizophrenia associated with atopic diseases among 808,559 individuals born between 1977 and 1992.

In total, 3539 individuals were diagnosed with schizophrenia during 7,169,984 person-years of follow up from 1992 through 2008.

The researchers found that hospital contact for any atopic disorder was associated with a significantly increased risk for schizophrenia, at a rate ratio (RR) of 1.35, after adjustment for calendar year, age, gender, a family history of psychiatric disorders, and degree of urbanization.

The significantly increased risk for schizophrenia associated with atopic disorders was mainly driven by hospital contact for asthma, at an adjusted RR of 1.46.

The increased risk for schizophrenia associated with other atopic disorders was only significant when they were combined as a group, at a RR of 1.27, after adjustment for calendar year, age, and gender, and lost significance after further adjustment for a family history of psychiatric disorders and degree of urbanization.

Pedersen and team conclude: "This study indicates the existence of an association between atopic disorders in general and asthma in particular and the risk of developing schizophrenia."

They add: "The results thus lend further credit to the emerging consensus that immune or inflammatory processes are involved in the pathophysiology of schizophrenia.

"However, the other investigated atopic disorders… only significantly increased the risk of schizophrenia if they were collapsed into one group."

By Mark Cowen

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