Metformin treatment significantly improved depressive symptoms in patients with type 2 diabetes, according to a study published in the Journal of Affective Disorders.
The prevalence of type 2 diabetes (T2D) has risen dramatically, with over 400 million people affected globally. Research has established a strong association between T2D and depressive symptoms, which exacerbate the disease’s outcomes. Existing treatments for depression, such as antidepressants, may worsen metabolic control, necessitating alternatives that address both conditions.
Yating Yang and colleagues conducted a 24-week longitudinal study to examine whether metformin, a first-line medication for T2D, could also alleviate depressive symptoms.
A total of 475 participants with first-episode T2D and depressive symptoms, aged 18 to 60, were recruited from the endocrinology outpatient clinic of Chaohu Hospital of Anhui Medical University between January 2021 and February 2024. Inclusion criteria required patients to meet clinical thresholds for T2D diagnosis and to score 10 or higher on the depression subscale of the Depression Anxiety Stress Scale-21 (DASS-21). Patients were excluded if they had previously used glucose-lowering medications, antidepressants, or insulin, or if they experienced severe diabetes complications during the study period.
Participants were divided into two groups; the group receiving metformin comprised 350 participants, while 125 participants were treated with alternative glucose-lowering medications. Demographic and medical data, including sex, marital status, education, and presence of hypertension or dyslipidemia, were also collected.
The DASS-21 was administered at baseline and after 24 weeks to evaluate changes in depressive, anxiety, and stress symptoms. To ensure objectivity, the identity of participants’ prescribed treatments was blinded from evaluators. Blood samples were collected and analyzed for fasting blood glucose and glycated serum protein, among other metrics, to monitor metabolic status during the intervention.
Yang and colleagues observed significant improvements in depressive symptoms among patients treated with metformin over the 24-week period. At the study’s conclusion, DASS-21 scores showed a marked reduction in depression, anxiety, and stress levels in the metformin group compared to the non-metformin group. Patients receiving metformin demonstrated a significant decrease in depression scores, dropping from an average of 16.01 at baseline to 12.75 at week 24. In contrast, participants in the non-metformin group saw smaller reductions, with scores falling from 15.68 to 14.84 during the same period.
Logistic regression identified key risk factors for depression, including female sex (odds ratio [OR] = 2.04), the presence of hypertension (OR = 2.67), dyslipidemia (OR = 2.44), and the absence of metformin use (OR = 4.21).
The authors acknowledged that the DASS-21 does not align with ICD-10 diagnostic criteria, which limits the generalizability of findings. Further, the lack of randomization in treatment assignments could introduce bias.
Overall, this study underscores the dual benefits of metformin in improving glycemic control and alleviating depressive symptoms in T2D patients, particularly among individuals with less complex comorbid conditions.
The study, “Metformin treatment improves depressive symptoms associated with type 2 diabetes: A 24-week longitudinal study,” was authored by Yating Yang, Xi Zhang, Yun Zhang, Jianyong Zhao, Jingfang Jia, Huanzhong Liu, and Suqi Song.
