Prevalence and Incidence of Psychiatric Disorder Treated Episodes in an Occupational Cohort: Sociodemographic and Work Trends across a 6 Year Period

Background and Objective(s):Few investigations have addressed psychiatric disorders among workers in the oilfield services industry. The study objectives were to describe the annual prevalence and incidence of treated psychiatric disorder episodes from 2005 to 2010 and their distribution by subgroups among US employees of a large oilfield services corporation.

Methods: In this historical cohort study, yearly prevalence and incidence rates of any DSM-IV-TR treated psychiatric disorder episode of care were calculated for the years 2005 through 2010. Differences in rates by subgroups were assessed using chi-square tests of significant associations at a significance level of P≤ .05.                 

Results: The sample size ranged from 18,744 in 2005 to 25,922 in 2010. The 12-month prevalence ranged from 3.6% in 2008 to 4.3% in 2009. During 2006-2010, the 12-month incidence ranged from 3.2% in 2008 to 3.8% in 2009. Rates varied by all variables (P≤.05). For example, across all study years, prevalence was highest for females, those 35-44 years old, Caucasians and Colorado workers, but increased over time for minority groups and Wyoming employees.  Prevalence was greatest for salaried workers, those with tenure of 6 to 10 years, and employees in administrative/clerical or technical support jobs. Prevalence was lowest for operators and professionals throughout all years. Similar incidence rate trends were observed.

Conclusion: The prevalence and incidence of psychiatric disorder episodes varied by subgroups and across time. Findings may inform mental health promotion programs in the oil and gas industry.