Background: Pharmacological treatment is the criterion standard in delusional disorder (DD). No second-generation antipsychotic (SGA) is specifically authorized for the treatment of DD.
Aims: To evaluate the evidence available on pharmacological treatments in adults with DD and to compare first-generation antipsychotics (FGA) versus SGA.
Methods: A systematic review on pharmacological treatment of DD following the PRISMA methodology was conducted. We selected the best evidence available and analyzed it critically assessing both, biases and quality, to finally perform a narrative and quantitative synthesis.
Results: The evidence available was mainly limited to observational studies and case series. There were no randomized clinical trials. Three hundred eighty-five DD cases were included (177 of which were on SGAs). Overall, antipsychotics achieved a good response in 33.6%% of the patients. As a group, FGAs showed significant superiority compared to SGAs (good response rates were 39% vs 28%, respectively). We did not find superiority of any specific antipsychotic over another.
Conclusions: There is no strong evidence to make definite recommendations, although antipsychotics in general seem to be an effective treatment for DD with a slight superiority in favor of FGAs as compared with SGAs. Existent data are, albeit, scarce and specific clinical trials on DD, are strongly recommended.