Incidence and prevalence of 'diagnosed OCD' in a primary care, treatment seeking, population.

Objective. To obtain valid and accurate estimates of the incidence and prevalence of OCD in a treatment-seeking primary care population and to compare these estimates with estimates from epidemiological community studies. Methods. A retrospective cohort study (1996-2007) was conducted in a GP research database with longitudinal electronic patient record data of 800,000 patients throughout The Netherlands. OCD was ascertained and classified by systematic review of computerized longitudinal medical records. Age and gender specific incidence rates were calculated per calendar year as the number of newly diagnosed cases per 100 person years. Results. Among 577,085 eligible patients, 346 patients were newly diagnosed with OCD resulting in a 1-year treatment-seeking incidence of 0.016% (95% CI: 0.014-0.018). Across the entire study period, a total of 780 patients had a clinical diagnosis of OCD resulting in a treatment-seeking prevalence of 0.14% (95% CI: 0.126-0.145). The incidence rate was highest among women and between the age of 20 and 29. No significant changes over time were observed. Conclusions. The incidence rate and prevalence of OCD in treatment-seeking GP patients are at least 3 times lower than estimates known from the most conservative epidemiological community studies, suggesting that OCD may be under recognised and under treated

Incidence rates and risk factors of bipolar disorder in the general population: a population-based cohort study.

To estimate the incidence rates (IRs) of bipolar I and bipolar II disorders in the general population according to sociodemographic population characteristics. A cohort study (during the years 1996-2007) was conducted in a general practitioners research database with a longitudinal electronic record of 800000 patients throughout the Netherlands [the Integrated Primary Care Information (IPCI) database]. Cases of bipolar disorder were identified and classified by systematic review of medical records. Age- and gender-specific IRs were calculated per calendar year, degree of urbanization, and degree of deprivation. The overall IR of bipolar disorder was 0.70/10000 person-years (PY) [95% confidence interval (CI): 0.57-0.83]; the IR of bipolar I disorder was 0.43/10000 PY (95% CI: 0.34-0.55) and the IR of bipolar II disorder was 0.19/10000 PY (95% CI: 0.13-0.27). Two peaks in the age at onset of the disorder were noticed: one in early adulthood (15-24 years; 0.68/10000 PY) and a larger peak in later life (45-54 years; 1.2/10000 PY). In bipolar II disorder, only one peak, in the 45-54 year age category (IR 0.42/10000 PY), was found. The IRs of bipolar disorder were significantly higher in deprived areas. Similar rates were found for men compared to women and in urban compared to rural areas. No association was found between the onset of first (hypo)manic episode and month or season of birth. We found two peaks in the age at onset of bipolar disorder, one in early adulthood and one in later life, the former consisting mainly of bipolar I disorder subjects. The incidence of bipolar disorder is higher in deprived areas. The onset of bipolar disorder is not associated with gender, urbanization, or month or season of birt

Annual incidence rate of schizophrenia and schizophrenia spectrum disorders in a longitudinal population-based cohort study.

Longitudinal incidence studies of schizophrenia spectrum disorders (SSD) performed in mental health service organizations are prone to confounding factors not found in research performed in the general population. To estimate the incidence rates (IRs) over a 10-year period of SSD (broadly defined) and schizophrenia (narrowly defined) in the general population and to analyze associated risk factors. A cohort study (1996-2006) in a large general practitioners research database was conducted with longitudinal medical records of 350,524 patients throughout the Netherlands. Cases of SSD were identified and classified by systematic review of medical records. Age- and gender-specific IRs were calculated per calendar year, date of birth, degree of urbanicity and deprivation. Overall IR of SSD in this population was 22/100,000 person years (PY) (95 % CI 19-24). IR of schizophrenia was 12/100,000 PY (95 % CI 10-14). Period prevalence was 3.5 per 1,000 PY. IRs were higher in men compared to women, had a peak at age 15-25 years, decreasing rapidly after 25 years by 40 % per 10 years. IRs of SSD were significantly higher in urban areas, irrespective of deprivation. No association was found between IRs of SSD and living in deprived areas or month of birth. There was no si IRs of SSD are higher in urban areas, independent of social deprivation. Age- and gender-specific differences in IR were found. The magnitude of these differences was larger in narrowly defined schizophrenia than in SSD