Background Studies have suggested that developing good trends in clinical practices in adherence to the recommended processes and guidelines for basic care have been associated with good health outcomes. However, no previous studies have explored trends in psychiatric practices and their impact on relapse among patients with severe mental disorders. Methods: We conducted a retrospective chart review of 401 patients with severe psychiatric disorders selected by systematic random sampling technique. Trends in clinical practice were assessed by a tool adapted from published evidence based on advice from well-known experts in psychiatric practice. A univariable and multivariable logistic regression model was used to investigate the association between psychiatric practices and relapse. Results This study provided evidence of a significant deficit in adherence to the recommended practices of basic care. The vast majority of professionals were not following the appropriate psychiatry history-taking format at first contact (73.6%), not documented the reasons for drug discontinuation (88.5%), did not follow the correct guideline of shifting across psychrotrophic medications (86.8%), and did not put their name or signature on the chart (61.8%). In multivariable analysis, not following psychiatric history taking format at first contact 1.63 (1.04, 2.56)], the diagnosis of bipolar disorders [4.85 (2.01, 8.36)], drug discontinuation after a short duration of treatment [1.21 (1.02, 2.42)], poor documentation of patient data during follow up [3.10 (2.35, 4.43)], absence of name and signature of treating physician on the chart [7.58 (2.64, 21.79)], and failing to treat medication side effect [2.55 (1.02, 6.39)] were found to significant predictors of relapse among the participants. Conclusions The findings provided evidence of notably higher rates of deficits in adherence to the existing guideline of basic psychiatric care, which resulted in a higher risk of relapse among patients with severe psychiatric disorders.