Background:
Most of the evidence from randomised clinical trials (RCTs) of schizophrenia comes from countries with different ethnic, cultural and economic backgrounds from Mexico (population ~120 million, lifetime prevalence of schizophrenia ~0.7%). The external validity of these trials might be questionable where it comes to application within Mexico, so local trials supporting or refuting the validity of findings from elsewhere are important.

Objectives:
To perform a broad overview of RCTs for people with schizophrenia in Mexico.

Methods:
Types of studies: We included all RCTs undertaken in Mexico in people with schizophrenia.
Search: The Information Specialist of the Cochrane Schizophrenia Group (CSzG) searched the CSzG register for the word ‘Mexico’. There are no language, date, document type, or publication status limitations for the inclusion of records into the register. We supplemented the search by contacting authors and the pharmaceutical industry.

Results:
We screened 290 references and included 26 studies. We also found 11 reports of ongoing studies (Figure 1).
Since the first identified trial in Mexico (1971), a total of 1294 people with schizophrenia have been randomised in Mexico. Nine of these trials were of short duration (< 12 weeks) and 11 were long-term (> 26 weeks), the rest were medium-term. The majority of studies evaluated drugs (80%), and the minority (20%) assessed non-pharmacological interventions. The pharmaceutical industry has produced 38% of clinical trials in Mexico accounting for 23% of the people ever randomized in Mexico (Figure 2).

Conclusions:
In Mexico, a country with approximately one million people living with schizophrenia, the number of people randomised since 1971 is only 1294. Evidence has largely flowed from the northern hemisphere – a very different care culture – and even evidence produced there may even be problematic to apply in those localities.

Patient or healthcare consumer involvement:
Mexican patients and clinicians deserve better. Further south, in Brazil, there are examples of schizophrenia trials which have been designed with local clinical needs in mind, and the river of evidence has flowed in a different direction at last. It is time for high-quality Mexican evidence to be produced for the people of Mexico but to inform everyone.