The primary purpose of this study is to identify whether, after adjustment for confounders via stratification on a propensity score and adjustment for calendar year, the combined endpoint consisting of #1 to #4 (1. switching back to Concerta, 2. changing the use of immediate release [IR] methylphenidate, 3. beginning a new attention deficit hyperactivity disorder [ADHD] medication, or 4. stopping both Concerta and the long acting [LA] methylphenidate {authorized generic [AG] methylphenidate or equivalent generic [EG] methylphenidate} that was begun on the index date), differs between participants who switch from branded Concerta to the EG formulations versus participants who switch from branded Concerta to the AG formulation.

This is a retrospective cohort study based on a health claims database, the Truven Commercial Claims and Encounters (CCAE) database. Participants will enter the cohort when, after using Concerta continuously for at least 60 days after October 3, 2012, they receive a dispensing of the AG or EG formulation within 15 days of the end of the days of Concerta supplied. The date of that dispensing of the AG or EG formulation is the participants index date. This study will track various events, example, back-switches, and methylphenidate dose changes over time (the 60 days before the switch from Concerta to an AG or EG generic compared to the 60 days after that switch).

Inclusion Criteria:

• Male or female participants 6 to 65 years of age
• Have been in the database continuously for at least 183 days after June 1, 2012
• Have a diagnosis of attention deficit hyperactivity disorder (ADHD)
• Use Concerta (a brand of methylphenidate) for at least 60 days and receive a dispensing of the authorized generic (AG) or equivalent generic (EG) formulation within 15 days of the end of the days of Concerta supplied. The date of that dispensing of the EG or AG formulation is the participants index date
• Have an index date greater than or equal to (>=) Dec 1, 2012 and less than or equal to (<=) Dec 3, 2014, the former to reflect the fact that the EG preparation became available in December, 2012, and the latter to allow 60 days follow up <= Jan 31, 2015, which is the end date for the available data

Exclusion Criteria:

• Their age or sex is not specified in the database
• At any time after June 1, 2012 and before their index date they receive a diagnosis of Renal insufficiency or Hepatic insufficiency or Schizophrenia or Bipolar disorder or mania or Anxiety or Glaucoma or Tourettes's syndrome or Nervous tension or Narrowing of esophagus, stomach or intestine
• At any time from 183 days before they join the cohort to 60 days after their index date, they a) are diagnosed as pregnant; b) are dispensed any prescription medication commonly used to treat seizures or migraines c) are dispensed any antidepressant or antipsychotic medication
• At any time from 60 days before their index date to 60 days after their index date they a) Receive a dispensing of methylphenidate in any form other than a non-chewable tablet, example, if they receive methylphenidate as a patch, suspension, syrup, or chewable tablet b) Receive a dispensing of long acting (LA) methylphenidate other than Concerta, the AG formulation or an EG formulation
• Concerta is dispensed to the participant <= 3 days after the index date

Participants in the Truven Commercial Claims and Encounters (CCAE) database who enroll in the study will have a confirmed diagnosis of ADHD and continuously used Concerta brand of methylphenidate for at least 60 days and receive a dispensing of the AG or EG formulation within 15 days of the end of the days of Concerta supplied.