Diabetes and psychiatric illness in the total population of Stockholm Per Wändell a, ⁎, Gunnar Ljunggren b,c , Lars Wahlström a , Axel C. Carlsson a,d a Centre for Family Medicine, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden b Public Healthcare Services Committee Administration, Stockholm County Council, Box 6909, SE-102 39 Stockholm, Sweden c Medical Management Centre, Department of Learning, Informatics, Management and Ethics, Karolinska Institutet, Berzelius väg 3, SE-17177 Stockholm, Sweden d Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden abstract article info Article history: Received 8 May 2014 Received in revised form 23 June 2014 Accepted 23 June 2014 Keywords: Depression Psychosis Schizophrenia Anxiety Administrative databases Primary care Gender differences Age differences Epidemiology Objective: Concomitant psychiatric disorders in people with diabetes affect morbidity and mortality. We aimed to study psychiatric morbidity in people with diabetes and the general population using administrative health care data in Stockholm County. Methods: The study population included all living persons who resided in Stockholm County, Sweden, on January 1, 2011 (N = 2,058,408). Subjects with a diagnosis of diabetes were identified with data from all consultations in primary health care, specialist outpatient care and inpatient care during the time span 2009–2013. As outcome, information was obtained on all consultations due to any psychiatric diagnosis as well as, specifically, schizophre- nia, bipolar disorders, depression, and anxiety disorders, in 2011–2013. Analyses were performed by age group and gender. Age-adjusted odds ratios (ORs) with 95% confidence intervals (95% CI) for women and men with di- abetes, using individuals without diabetes as referents, were calculated. Results: Age-adjusted OR for all psychiatric diagnoses among people with diabetes was 1.296 (95% CI 1.267–1.326) for women and 1.399 (95% CI 1.368–1.432) for men. The greatest excess risk was found for schizo- phrenia, with OR 3.439 (95% CI 3.057–3.868) in women and 2.787 (95% CI 2.514–3.089) in men, with ORs be- tween 1.276 (95% CI 1.227–1.327) and 1.714 (95% CI 1.540–1.905) for the remaining diagnoses. Conclusion: The prevalence of psychiatric disorders is elevated in people with diabetes, which calls for preventive action to be taken to minimize suffering and costs to society. © 2014 Elsevier Inc. All rights reserved. Introduction There are several links between somatic diseases and psychiatric disorders. Diabetes and depression may influence each other in differ- ent ways [1–3]. Insulin resistance has been shown to be associated with depression [4], and people with diabetes have a higher risk of co- morbid depression [5–7]. Moreover, depression has been shown to be a risk factor for incident diabetes [6,8,9], and depression has also been linked to inflammation and increased oxidative stress [10,11]. Other psychiatric conditions have been shown to be commonly associated with diabetes, and to affect somatic health and outcomes among people with diabetes [12], including schizophrenia (partly drug induced) [13], bipolar disorder [14], generalized anxiety as well as panic disorders [15]. There are signs of a dysregulated immune system in many psychi- atric disorders [16], and some antipsychotic drugs are associated with weight gain and disturbed glucose metabolism [17]. Besides, there are genetic links between diabetes and schizophrenia [18–20]. Somatic health among people with psychiatric disorders is not al- ways given high priority [21]. For example, people with diabetes and depression [22], or anxiety [23], have been shown to have poorer met- abolic control, and there is also an increased risk of hypoglycemia in people with both diabetes and depression [24]. People with both diabe- tes and depression have been shown to have an increased risk of both cardio-vascular and all-cause mortality [25–27]. Besides, mental health among people with diabetes does not always receive full attention. The quality of life among people with diabetes and concomitant mental dis- orders is shown to be substantially affected [28], and people with type 1 diabetes are at increased risk of suicide [29]. Many studies of psychiatric disorders in people with diabetes have been based on the registration of depressive symptoms or the use of an- tidepressant drugs [8]. Less is known about clinically diagnosed individ- uals in the community. In Stockholm County, with a total population of more than two mil- lion people, all diagnosis codes and reasons for hospitalizations and con- sultations in primary health care and specialist care are recorded and stored in a large administrative database. This comprehensive data Journal of Psychosomatic Research 77 (2014) 169–173 ⁎ Corresponding author at: Centre for Family Medicine, Karolinska Institutet, Alfred Nobels Allé 12, 141 83 Huddinge, Sweden. Tel.: +46 8 52488727; fax: +46 8 52488706. E-mail address: per.wandell@ki.se (P. Wändell). http://dx.doi.org/10.1016/j.jpsychores.2014.06.012 0022-3999/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Journal of Psychosomatic Research