Pharmacological treatment of patients with schizophrenia and other psychoses get scientific backing of its main clinical trials. Methodological guarantees these test tend to strengthen the internal validity of the results at the expense of external validity and the ability to generalize the results to the clinical population. For this reason, and to minimize the shortcomings of external validity while maintaining internal validity, has been promoted in recent years to carry out large clinical trials based on clinical practice. This type of test expands the criteria for inclusion, limiting the exclusion criteria to incorporate as many patients as possible. The first and most significant of these trials was the CATIE trial (Lieberman et al, 2005).

Discuss eligibility patients admitted during the year 2009 in a psychiatric inpatient unit with a diagnosis of schizophrenia for participation in CATIE.

A total of 145 patients (27.6% females, mean age 39.6+/−12.8 years), consecutively admitted to an inpatient psychiatric ward with a clinical diagnosis of schizophrenia or other psychoses were assessed to test if they would fulfill criteria for participation in CATIE.

60 (41.4%) patients did not fulfill CATIE inclusion criteria. Mental retardation (n = 22, p < 0.001), absence of consent (n = 15, p < 0.001) and refusal to take oral medication (n = 12, p < 0.001) were the main factors responsible for not meeting criteria. Meeting the criteria was not significantly related to gender or specific diagnosis.

The 41.38% of patients did not meet criteria for participation in the CATIE study.