Chronic thromboembolic pulmonary hypertension and schizophrenia.

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by persistent thromboemboli in the pulmonary arteries, which cause pulmonary hypertension and result in right heart failure and death [1]. CTEPH occurs in 2–4% of patients with acute pulmonary embolism (PE) [2], indicating a pathological relationship between the two diseases. Several common risk factors for CTEPH and PE have been reported, such as certain medical therapies, thrombophilia, and a genetic predisposition [1,3,4]. However, no report has addressed the association between CTEPH and schizophrenia, although an association between PE and schizophrenia has been suggested due to enhanced blood clotting from the long-term administration of antipsychotic drugs and immobility syndrome [5]. We report a significantly higher prevalence of schizophrenia in patients with CTEPH than in those with pulmonary arterial hypertension (PAH) and the general population. We treated 110 patients with CTEPH (63.1 ± 1.3 years, 86 women) and 150 patients with PAH (48.7± 1.4 years, 110women) diagnosed at our hospital between December 1992 and June 2015. The diagnosis of CTEPH and PAH, and schizophrenia was based on the current CTEPH guideline [6] and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, respectively. Themean pulmonary arterial pressure was comparable between the two groups (CTEPH 42.0 ± 0.9 mm Hg, PAH 43.7 ± 1.5 mm Hg, P = 0.353). The prevalence of schizophrenia was compared between patients with CTEPH and PAH, and the general Japanese population in 2008 according to the Japanese government's statistics [7,8] using Fisher's exact test with a significance level of P b 0.016 for Bonferroni correction. The prevalence of schizophrenia