What is the evidence.
See evidence matrix  in Epistemonikos later

We found three systematic reviews [1],[2],[3] including five primary studies [4],[5],[6],[7],[8], of which two correspond to randomized controlled trials [4],[8]. This table and the summary in general are based on the latter.

What types of patients were included

Both studies included adult patients with a recent diagnosis of schizophrenia (DSM IV) [4],[8]. One study included patients with first-episode psychosis only within the last two years prior to the initiation of the study [4].

What types of interventions were included

Both studies compared long-acting injectable risperidone to oral risperidone [4],[8]. In one study patients were treated with oral antipsychotics for an average of 7.2 months before randomization, and then for 6 more months [4]. The other study maintained treatment for 12 weeks [8].

What types of outcomes
were measured

The reviews addressed the following outcomes:

- Acceptance by patients to switch from oral to injectable risperidone.
- Non-adherence was defined as the absence of medication during 14 days or more.
- Subjective perception of patients regarding adherence by the Rating Scale of Medication Influences (ROMI) [8].

One study measured changes in the volume of white matter in the frontal lobe by using magnetic resonance imaging (MRI) and neurocognitive assessment by CogState computerized cognitive battery [4]. 

To whom this evidence does and does not apply

• This evidence applies to all adult patients with first-episode schizophrenia. 

• The outcomes presented in this summary are those considered critical for decision making by the authors of this summary. 

• The certainty of the available evidence is very low so it is not possible to make an adequate risk/benefit balance.

• Despite the high rate of non-adherence in these patients, there is still underuse of depot antipsychotics, particularly in patients who present with a first-episode psychosis. One study [9] observed three factors that influenced that pattern: (a) limited availability of long-acting second generation antipsychotics; (b) preconceived notion of rejection by the patient; and (c) patient's skepticism based on an absence of previous relapses, demonstrating the importance of a patient-centered approach, evaluating this treatment in all patients with first-episode psychosis.
• Independent of the therapeutic option chosen, it is important to inform the patient about the existing uncertainty of the evidence. 

• The certainty of the evidence is very low, so it is not possible to make an appropriate cost/effectiveness analysis.

Differences between this summary and other sources

• The conclusions of our summary are consistent with the conclusions of the individual systematic reviews identified.
• Clinical guidelines recommend the use of depot antipsychotics as first line in schizophrenic patients with adherence problems, frequent recurrences, which pose a risk to others, with low insight, for patient preference or when there is a previous positive response. Second generation antipsychotics are also recommended in cognitive deficits and social isolation [10].

• The probability that the main findings of this summary change in the future is very high, due to the very low certainty of the evidence so far.
• There are at least three randomized controlled trials [11],[12],[13] which have not yet been included in systematic reviews. So a new review including these would increase the certainty of the evidence.