Chandler 1989.

Methods	A patient report of 2 boys on methylphenidate treatment. 1 with preexisting tics that were aggravated by stimulants and 1 with stimulant induced tics
Participants	Case 1 Diagnosis of ADHD: DSM‐III (subtype: not stated) Age: 12 years old IQ: > 70 Sex: male Ethnicity: not stated Country: USA Comorbidity: not stated Comedication: not stated Sociodemographics: not stated Case 2 Diagnosis of ADHD: DSM‐III (subtype: not stated) Age: 9 years old IQ: > 70 Sex: male Ethnicity: not stated Country: USA Comorbidity: none Comedication: not stated Sociodemographics: not stated
Interventions	Case 1 Methylphenidate type: not stated Methylphenidate dosage: 0.2 mg/kg Administration schedule: twice daily Duration of treatment: 1 month Treatment compliance: not stated Case 2 Methylphenidate type: not stated Methylphenidate dosage: 0.2 mg/kg Administration schedule: twice daily Duration of intervention: not stated Treatment compliance: not stated
Outcomes	Non‐serious adverse events: Case 1: after a month, the child's mother reported motor and phonic tics again Case 2: he was treated first with methylphenidate, and then with nortriptyline, with both drugs he manifested severe facial grimacing and phonic tics. Apparently, the tics had only occurred in the past when the child was treated with methylphenidate
Notes	Funding/vested interests/authors affiliations: not stated Key conclusions of the study authors: we report 2 cases of AD/HD children, 1 with pre‐existing tics that were aggravated by stimulants and 1 with stimulant induced tics. With combined stimulant/L‐tryptophan treatment there was sustained improvement in AD/HD symptoms and no motor or phonic tics. Side effects such as hypomania, hyperreflexia, and diaphoresis have been reported in patients on the combination of a monoamine oxidase inhibitor and tryptophan. By itself, L‐tryptophan may be mildly sedating. In light of such a favorable side effect profile, and no evidence for adverse interaction with stimulants, and at least some rationale from preclinical research, it should be investigated further as a means of alleviating some of the harsh consequences of psychostimulant treatment in AD/HD Supplemental information regarding diagnosis and IQ received through personal email correspondence with the authors in September 2013 (Gualtieri 2013 [pers comm])