Lakic 2012.

Methods	A cohort study of the influence of methylphenidate treatment on the occurrence of tics and exacerbation of pre‐existing tics
Participants	Number of participants screened: not stated Number of participants included: 68 Diagnosis of ADHD: DSM‐TR‐IV (subtype: not stated) Age: range 7‐15 years old IQ: > 70 Sex: not stated Methylphenidate‐naïve: not stated Ethnicity: not stated Country: Serbia Comorbidity: tic disorder 9.7% Comedication: not stated Sociodemographics: not stated Inclusion criteria: DSM‐TR‐IV diagnosis of ADHD Currently or recently treated with methylphenidate sustained release Exclusion criteria: Mental retardation
Interventions	Methylphenidate type: sustained‐release Methylphenidate dose range: 18‐36 mg/day (individualised dose) Administration schedule: not stated Duration of intervention: > 6 weeks, up to 6 months Treatment compliance: not stated
Outcomes	Non‐serious adverse events: Assessment of the occurrence of tics at the time of diagnosis, start of therapy and during methylphenidate treatment. Furthermore, monitoring (type, intensity, duration) of pre‐existing tics during methylphenidate treatment
Notes	Sample calculation: not stated Ethics approval: not stated Funding: no funding Authors' affiliations: not stated Key conclusions of the study authors: tics as a side effect of sustained‐release methylphenidate treatment in our patients was predominantly motor, of mild intensity and transient in nature, and did not require cessation of therapy Exclusion of methylphenidate non‐responders/children who have previously experienced adverse events on methylphenidate: not stated Supplemental outcome data and information about IQ and funding were received through personal email correspondence with the authors in October 2013 (Lakic 2013 [pers comm])