To compare the therapeutic effects of quetiapine and olanzapine in the treatment of patients with dementia related organic brain disorders and their impact on internal environment indicators.

A total of 240 patients with organic brain disorders caused by Alzheimer's disease who were admitted and diagnosed at the Department of Psychiatric of the Fourth Affiliated Hospital of China Medical University from July 2017 to January 2020 were selected. They were randomly divided into either a quetiapine group or an olanzapine group, with 120 cases in each group. Patients in the olanzapine group were given oral olanzapine orally, while those in the quetiapine group were given oral quetiapine. The course of the treatment was 6 weeks. The curative effect, positive and negative syndrome scale (PANSS) scores, and internal environmental indicators [prolactin, leptin, fasting blood glucose (FBG), insulin resistance (IR) triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), pH, partial pressure of carbon oxide (PaCO₂), standard bicarbonate (SB), base excess (BE), buffer base (BB), acetic acid, K⁺, Na⁺, Ca²⁺, and Mg²⁺] were recorded. The adverse reactions of all patients during treatment and within 6 weeks after treatment were recorded.

The numbers of patients with cure, significant improvement, improvement, and no improvement in the quetiapine group were 4, 34, 74, and 8 cases, respectively; the corresponding figures in the olanzapine group were 6, 24, 84, and 6 cases. There was no significant difference in the total effective rate between the quetiapine group and olanzapine group (93.33% vs 95.00%, respectively; χ²=0.303, P=0.582). Before treatment, there were no significant differences in the scores of positive symptoms, negative symptoms, and general psychopathology, and total score between the two groups (P＞0.05 for all). After treatment, all these scores of the two groups were significantly lower than those before treatment (P＜0.05 for all), but there were no statistically significant differences between the two groups (P＞0.05 for all). Before treatment, the internal environment indicators had no statistically significant differences between the two groups (P＞0.05). After treatment, the internal environmental indicators in the quetiapine group had no significant changes (P＞0.05), but prolactin, leptin, FBG, IR, TG, LDL-C, and TC were significantly increased in the olanzapine group (P＜0.05 for all). Compared with the quetiapine group, prolactin, leptin, FBG, IR, TG, LDL-C, and TC were significantly increased in the olanzapine group after treatment (P＜0.05 for all). In the quetiapine group, there were 6 cases of drowsiness, 4 cases of dry mouth, 8 cases of insomnia, and 4 cases of extrapyramidal reactions; the corresponding figures in the olanzapine group were 4, 5, 6, and 8 cases. The total adverse reaction rate did not differ significantly between the quetiapine group and olanzapine group (18.33% vs 19.17%, χ²=0.274, P=0.869).

Quetiapine and Olanzapine have similar therapeutic effects and adverse reactions in the treatment of dementia related organic brain disorders, but quetiapine has a relatively less effect on the internal environment of patients. For organic mental disorder patients with underlying diseases, quetiapine is recommended.