An Epidemiology Study of Treatment Resistant Depression in the United States (US)

Recruitment & Eligibility

Inclusion Criteria

Have been in the database for the past year (ignoring breaks of < 30 days)
Have not had, an excluded diagnosis or dispensing of an AD medication during the past year
Are aged 14 to 60 years (if in the CCAE or MCDC databases), or are aged greater than or equal to (>=) 65 years (if in the MCDR database). Age is defined as age on Jan 1, 2011. The boundary at age 60 for the first two databases is intended to avoid loss to follow-up due to transfer to Medicare at age 65. The boundary at age 65 for the MCDR database reflects the fact that very few people described by that database are aged less than 65

Exclusion Criteria

Participants will be excluded when they receive diagnoses Schizophrenia, Bipolar disorder including mania or Dementia

Study & Design

Primary Outcome Measures

Name	Time	Method
Incidence Rate of Treatment Resistant Depression	Up to 4 years	TRD will be defined as the failure of two medications, as marked by their replacement or supplementation with other medications using three alternative definitions. In one the time for a medication regimen to fail is limited to less than or equal to (\<=) 3 months and in the second the time for a medication regimen to fail is limited to \<= 6 months, both corresponding to the medication never providing adequate relief. In the third, the time for a medication regimen to fail will be limited to \<= 2 years, corresponding to the medication not providing permanent or very long lasting relief.
Treatment Resistant Depression as a Proportion of Pharmacologically Treated Depression	Up to 4 years	An episode of PTD begins when a member of the study cohort receives a dispensing of an antidepressant (AD) medication and receives a diagnosis of depression between 180 days before that dispensing and 30 days after that dispensing.
Incidence Rate of Treatment Resistant Depression by Age Group and Sex	Up to 4 years	TRD incidence will be stratified by age group and sex under each of the three definitions of failure of a medication regimen.
Incidence Rate of TRD as Separate Estimates for the Medicaid Population, the Medicare Population, and the Privately Insured Population	Up to 4 years	TRD incidence will be stratified by data population (database): Medicaid, Medicare, Privately insured.

Secondary Outcome Measures

Name	Time	Method
Incidence on TRD Based on Sensitivity Analysis	Up to 4 years	Sensitivity analyses are intended to clarify how the results of the present study will compare to the results of other studies that may define as The maximum time for failure of a regimen is changed to: 60, 120, 150, or 365 days, or is not limited; the requirement that a regimen include greater than or equal to (\>=) 28 days' supply of the antidepressant medication and antipsychotic medication (if present) is changed to \>= 42 days and 14 days supply; participants who get an excluded diagnosis are retroactively excluded from the study cohort; or the definition of an incident case adds a requirement for no depression diagnosis in the prior year.
Number of Participants With Selected Markers for Severity of Depression	Up to 4 years	The following markers of severity will be tabulated during the PTD episodes and stratified according to whether the participant develops or does not develop TRD during the study period: Electro-convulsive therapy, hospitalization with a diagnosis of depression, receiving a diagnosis of suicidal thoughts, receiving a diagnosis of self-harm, emergency department visit with a diagnosis of injury, emergency department visit with a diagnosis of poisoning.

Recruitment & Eligibility