Delusional disorder is traditionally considered a treatment resistant disorder. Antipsychotics are considered to be the treatment of choice despite information in this area is limited.

Describe a sample of DD inpatients, which received routine treatment.

To perform indirectly an efficacy analysis of long-acting injectable risperidone (RLAI) compared to oral risperidone and to others atypical antipsychotics.

Prospective observational study including 80 inpatients on DD, according to DSM-IV-TR, consecutively admitted over a period of 10 years, and who were treated with atypical antipsychotics. The sample was divided into three groups according to which antipsychotic received: RLAI, oral risperidone and other oral atypical antipsychotics (OAP). Sociodemographic data and clinical features at the first admission and indirect efficacy variables at follow-up were registered. For comparison purposes, ANOVA, Chi-square and Mann-Whitney test were used.

Twenty-four patients received RLAI (30%), 30 oral risperidone (37.5%) and 26 (32.5%) OAP. No statistically significant differences were found among the three treatment groups regarding demographic data, reason for hospitalization and psychopathology at admission. RLAI group showed a greater adherence to follow-up (15/24 with> 75% of visits) and percentage of maintenance at the end of the period. In addition, the RLAI group required less frequently treatment with antidepressants (n = 5/24, 20.8%) and benzodiazepines (54.2% vs 65.4% in other oral atypical antipsychotics).

Treatment with RLAI in delusional disorder improves adherence to follow-up in these patients. On the other hand, patients treated with RLAI require less frequently use of other psychoactive drugs.