Standard approaches to cognitive remediation can suffer from limited skill transferability to
patients’ life. Complex virtual environments (VEs) enable us to create ecologically valid remediation
scenarios while preserving laboratory conditions. Nevertheless, the feasibility and efficacy of these
programs in psychiatric patients are still unknown. Our aim was to compare the feasibility and
efficacy of a novel rehabilitation program, designed in complex VEs, with standard paper–pencil
treatment in patients with schizophrenia and major depressive disorder. We recruited 35 participants
to complete a VE rehabilitation program and standard treatment in a crossover pilot study. Twenty-
eight participants completed at least one program, 22 were diagnosed with schizophrenia and 6
with major depressive disorder. Participant’s performance in the representative VE training task
significantly improved in terms of maximum achieved difficulty (p ≤ 0.001), speed (p < 0.001) and
efficacy (p ≤ 0.001) but not in item performance measure. Neither the standard treatment nor
the VE program led to improvement in standardized cognitive measures. Participants perceived
both programs as enjoyable and beneficial. The refusal rate was higher in the VE program (8.6%)
than in the standard treatment (0%). But in general, the VE program was well-accepted by the
psychiatric patients and it required minimal involvement of the clinician due to automatic difficulty
level adjustment and performance recording. However, the VE program did not prove to be effective
in improving cognitive performance in the standardized measures