Haloperidol 1973.

Study characteristics
Methods	Randomisation: unclear, randomisation assumed due to double‐blinding. Allocation: procedure not described. Blinding: double‐blind, all participants received both (placebo) tablets and (placebo) liquid, no further details. Duration: 90 days. Design: parallel. Location: single‐centre. Setting: inpatient.
Participants	Diagnosis: chronic schizophrenia (clinical diagnosis), all had previously responded to haloperidol and were adequately maintained on it. N = 49. Gender: 24 men, 20 women. Age: mean 42.5 years. History: duration stable‐ all stabilised for 30 days on haloperidol concentrate, duration ill‐ n.i., but mean duration of hospitalisation 13.7 years, number of previous hospitalisations‐ n.i., age at onset‐ n.i., severity of illness‐ mean BPRS 46.6 (16 items scale, rating system unclear), mean Clinical Global Impression of severity 4.9, baseline antipsychotic dose‐ mean 9.3 mg haloperidol/day.
Interventions	1. Drug: haloperidol tablets.* Flexible dose. Allowed dose range: n.i.. Mean dose: mean 8.8mg/day. N = 17. 2. Drug: haloperidol liquid.* Flexible dose. Allowed dose range: n.i.. Mean dose: 10.4 mg/day. N = 16. 3. Placebo: duration of taper: 0 days. N = 16. Rescue medication: antiparkinson medication was allowed.
Outcomes	Examined Relapse: deterioration of global state. Leaving the study early. Global state ‐ number of participants improved. Adverse effects (movement disorders). Suicide ideation. Unable to use/Not included Mental state: Brief Psychiatric Rating Scale (no SD/no predefined outcome of interest). Global state: Clinical Global Impression of Severity (no SD/no predefined outcome of interest). Behaviour: Nurses Observation Scale for Inpatient Evalutation (NOSIE) (no SD/no predefined outcome of interest). Adverse effects: laboratory (insufficient data/no predefined outcome of interest), vital signs (insufficient data/no predefined outcome of interest).
Notes	*Groups 1 and 2 were pooled for the purpose of this review.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear, randomisation assumed due to double‐blinding.
Allocation concealment (selection bias)	Unclear risk	Procedure not described.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blind, all participants received both (placebo) tablets and (placebo) liquid, no further details.
Blinding (performance bias and detection bias) Subjective outcomes	Unclear risk	Double‐blind, all participants received both (placebo) tablets and (placebo) liquid, no further details.
Blinding (performance bias and detection bias) Objective outcomes	Low risk	Double‐blind, all participants received both (placebo) tablets and (placebo) liquid, no further details.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Acceptable dropout rate (10%), which should not affect other outcomes (completer analysis).
Selective reporting (reporting bias)	Low risk	No evidence for selective reporting.
Other bias	Low risk	No clear other bias.