Ninety percent of people with depression also report suffering from additional cognitive disorders. However, despite the high prevalence, the effectiveness of cognitive training methods for mental illnesses has not yet been extensively researched.In our study, ninety-six adult patients with depressive symptoms were randomly assigned to one of two intervention groups or a passive control group. Ultimately, 48 patients successfully completed the training and assessments. The first intervention group completed computer-based cognitive training (three times a week for 20 min). The second intervention group practiced different memory strategies three times a week, in addition to completing the same computer-based cognitive training as the first intervention group.All groups demonstrated several improvements in cognitive performance and experienced benefits in everyday life over time. However, we found neither a significant group effect nor a significant time × group interaction effect for any of the measures. Despite this, on a descriptive level, the intervention groups showed improvements across all five cognitive test performance outcomes (especially attention and working memory) and displayed better scores in the post intervention assessment of the self-reported personal variables (well-being, emotional regulation and depressive symptoms). Approximately 50 % of the subjects in each group did not complete the training or the post intervention assessment and were excluded. We worked closely with healthcare professionals, therapists and doctors and were thus able to gather not only research results but also valuable experience in dealing with patients with depressive symptoms who are undergoing cognitive training. Our findings and experiences may have implications for optimizing the reintegration of people with depressive symptoms.