eAppendix 1: Search Strategy The PubMed search strategy employed the following terms (yielded 910 hits on 3/28/17): (“Dystonia”[Mesh] OR dystonia[tiab] OR “Torticollis”[Mesh] OR torticollis[tiab] OR wryneck[tiab] OR "Psychomotor Agitation"[Mesh] OR “psychomotor agitation”[tiab] OR restlessness[tiab] OR akathisia[tiab] OR "Akathisia, Drug-Induced"[Mesh] OR “drug-induced akathisia”[tiab] OR “tardive akathisia”[tiab] OR “Hypokinesia”[Mesh] OR hypokinesia[tiab] OR hypodynamia[tiab] OR bradykinesia[tiab] OR “Tardive Dyskinesia”[Mesh] OR “tardive dyskinesia”[tiab] OR "Drug-Related Side Effects and Adverse Reactions"[Mesh] OR “adverse drug event”[tiab] OR “adverse drug reaction”[tiab] OR “drug side effect”[tiab] OR "Treatment Outcome"[Mesh] OR “treatment outcome”[tiab]) AND ("Diphenhydramine"[Mesh] OR Diphenhydramine[tiab] OR "Histamine H1 Antagonists"[Mesh] OR “Histamine H1 Antagonists”[tiab] OR "Histamine H1 Antagonists" [Pharmacological Action] OR "Benztropine"[Mesh] OR benztropine[tiab]) AND ("Dopamine D2 Receptor Antagonists"[Mesh] OR “dopamine D2 antagonists”[tiab] OR "Dopamine D2 Receptor Antagonists" [Pharmacological Action] OR "Antiemetics"[Mesh] OR antiemetics[tiab] OR "Antiemetics" [Pharmacological Action] OR "Metoclopramide"[Mesh] OR metoclopramide[tiab] OR "Prochlorperazine"[Mesh] OR prochlorperazine[tiab] OR “Chlorpromazine” [MeSH] OR chlorpromazine[tiab] OR "Cholinergic Antagonists"[Mesh] OR “cholinergic antagonists”[tiab] OR "Cholinergic Antagonists" [Pharmacological Action] OR "Droperidol"[Mesh] OR droperidol[tiab]) The Cochrane search strategy employed the following terms (yielded 143 hits on 3/24/17): 1. (search terms 1 to 7): Dystonia, hypokinesia, extrapyramidal rigidity, psychomotor agitation, movement disorders, Drug-Related Side Effects and Adverse Reactions, treatment outcome 2. (search terms 8 to 10) Diphenhydramine, Histamine H1 Antagonists, Benztropine 3. (search terms 11 to 17) Dopamine D2 Receptor Antagonists, Antiemetics, Metoclopramide, Prochlorperazine, Chlorpromazine, Cholinergic Antagonists, Droperidol 4. Search strategy: (#1 or #2 or #3 or #4 or #5 or #6 or #7) and (#8 or #9 or #10) and (#11 or #12 or #13 or #14 or #15 or #16 or #17) The Embase search strategy employed the following terms (yielded 542 hits on 3/24/17): ‘extrapyramidal symptom’/exp OR ‘restlessness’/exp OR ‘psychomotor disorder’/exp OR ‘parkinsonism’/exp OR ‘tardive dyskinesia’/exp OR ‘adverse drug reaction’/exp OR ‘treatment outcome’/exp AND ‘diphenhydramine’/exp OR ‘Histamine H1 receptor Antagonists’/exp OR ‘benzatropine’/exp AND ‘dopamine 2 receptor blocking agent’/exp OR ‘Antiemetic agent’/exp OR ‘cholinergic receptor blocking agent’/exp) The Web of Science search strategy employed the following terms (yielded 36 hits on 3/28/17): #1 search: (TS=(dystonia OR torticollis OR "psychomotor agitation" OR restlessness OR akathisia OR "Drug-Induced Akathisia" OR hypokinesia OR "tardive dyskinesia" OR "Adverse Drug Event" OR "Adverse Drug Reaction" OR EPS OR "extrapyramidal symptoms")) #2 search: TS=(diphenhydramine OR "Histamine H1 Antagonists" OR benzatropine OR benztropine) #3 search: TS=("Dopamine D2 Receptor Antagonists" OR antiemetics OR metoclopramide OR prochlorperazine OR chlorpromazine OR "Cholinergic Antagonists" OR droperidol ) Combined search: #3 AND #2 AND #1 AND LANGUAGE: (English) AND DOCUMENT TYPES: (Article) All years Core collection (SCI-EXPANDED & SSCI) The Scopus search strategy employed the following terms (yielded 906 hits on 3/28/17): (TITLE-ABS-KEY ( dystonia OR torticollis OR "psychomotor agitation" OR restlessness OR "Drug-Induced Akathisia" OR hypokinesia OR akathisia OR EPS OR "extrapyramidal symptoms" OR "Adverse Drug Event" OR "Adverse Drug Reaction" ) AND TITLE-ABS-KEY ( diphenhydramine OR "Histamine H1 Antagonists" OR benzatropine OR benztropine ) AND TITLE-ABS-KEY ( "Dopamine D2 Receptor Antagonists" OR antiemetics OR metoclopramide OR prochlorperazine OR chlorpromazine OR "Cholinergic Antagonists" OR droperidol ) ) AND ( LIMIT-TO ( SRCTYPE,"j " ) ) AND ( LIMIT-TO ( DOCTYPE,"ar " ) OR LIMIT-TO ( DOCTYPE,"cp " )).