Study	Reason for exclusion
Akimoto 1966	Method: randomised. Participants: chronic schizophrenic participants. Intervention: perphenazine versus placebo.
Anon 2006	Method: randomised. Participants: schizophrenic participants. Intervention: perphenazine versus atypical antipsychotics.
Bennett 1961	Method: randomised. Participants: schizophrenia. Intervention: perphenazine, chlorpromazine. Outcome: no usable data.
Casey 1960	Method: randomised. Participants: schizophrenia. Intervention: perphenazine, chlorpromazine. Outcome: no usable data.
Hollister 1974	Method: not randomised.
Lapolla 1967	Method: randomised. Participants: hospitalised schizophrenic participants. Intervention: perphenazine in combination with amitriptyline versus chlorpromazine alone.
Loza 2001	Method: randomised. Participants: schizophrenic participants. Intervention: perphenazine versus atypical antipsychotics.
Nordic 1986	Method: randomised. Participants: psychiatric participants with tardive dyskinesia, not exclusively people with schizophrenia, how many participants had schizophrenia or related disorders was not reported.
Schulsinger 1958	Method: not randomised.
Smith 1959	Method: not randomised.
Svestka 1972	Method: not randomised.
Svestka 1974	Method: not randomised, but double‐blind. Cross‐over study, results of first phase not reported separately. Participants: acute exacerbation of psychosis (mainly schizophrenia) Intervention: perphenazine versus oxypertine (difficult to classify, probably a mid‐potency antipsychotic).
Vinar 1968	Method: randomised. Participants: schizophrenia. Intervention: perphenazine, chlorpromazine, levomepromazine, thioridazine. Outcome: no usable data, only total number of participants leaving early (no data for single drugs), no rating scale results (no mean, no SD).

SD ‐ standard deviation