According to the Global Burden of Disease (GBD-2019) report, mental disorders have been at the top of the global burden of disease list between 1990 and 2019. Depression ranks first among mental disorders with disability and psychosocial dependence. The worldwide prevalence rate of depression is 3.8% and it is a common disorder. The prevalence rate in adults is 5%, and the prevalence rate in adults aged 60 and over is 5.7%. According to the 2021 data from the US Centers for Disease Control and Prevention, compared to the general population, the rate of depression is 13.5% higher in older adults who need home healthcare services and 11.5% higher in hospitalized older adults. A recent systematic review and meta-analysis (2022) found that the global prevalence rate of depression in older adults was 28.4% and that the prevalence of depression in older adults is high, although there are variations by geographical location, diagnostic/screening tools, sample size, representativeness, and study quality. The isolation measures taken to prevent the spread of the COVID-19 pandemic have negative psychological effects on the protection of vulnerable groups, including older adults. Therefore, the pandemic is reported to have led to a significant increase in major depression cases globally, with an estimated 28.1% increase. With the COVID-19 pandemic, there is an increase in the demand for mental health services due to the increase in the incidence of depression and anxiety. Depression is more than a short-term emotional response to mood swings and psychological difficulties experienced in daily life. Especially recurrent and moderate or severe depression is an important health problem. The individual's daily life is negatively affected, functionality decreases and/or suicide may occur.

Depression is a serious mental disorder characterized by symptoms such as depressed mood or loss of interest/desire. In addition to these important symptoms, DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) criteria include sleep problems, changes in appetite/weight, psychomotor restlessness/agitation, loss of energy, concentration problems, feelings of worthlessness or guilt, and recurrent suicidal thoughts. Over time, this illness leads to cognitive and social dysfunction.

In the treatment of depression, multimodal treatment options need to be carried out simultaneously. Although there are known effective treatments for mental disorders, more than 75% of people in low- and middle-income countries do not receive treatment. Barriers to effective care include a lack of financial resources, lack of legal regulations, lack of trained health professionals, and stigma. Therefore, psychotherapeutic interventions in inpatient/outpatient mental health facilities for psychosocial rehabilitation are insufficient, and effective care management is needed to address this problem.

In the treatment of depression, only medication can be used due to various factors such as patient preference and economic reasons. However, despite medication, the disability and decreased functionality seen in patients are not sufficient for the rehabilitation of the patient. Insight into the disease and low compliance with treatment emphasizes the need for psychotherapies and psychosocial interventions. In this sense, cognitive-behavioral therapy approaches and family interventions are an essential complement to psychopharmacology.

Metacognitive Training (MCT) was created by Steffen Moritz (2007) focusing on psychosis. Studies conducted using MCT show that MCT is beneficial in patients with schizophrenia and psychosis, reduces the severity of delusions, and shows a positive effect even after 6 months of follow-up. Following these results, Metacognitive Training for Depression (D-MCT), which focuses on cognitive biases specific to depression, was developed based on the Metacognitive Training for Psychosis program. Metacognitive Training for Depression is a new treatment option for depression and is a variant of cognitive behavioral therapy that adopts a metacognitive perspective by focusing on changing cognitive biases and dysfunctional attitudes. In the first pilot study conducted by Jelinek et al. (2013), it was proven that there was a significant decrease in depressive symptoms, cognitive distortions, and rumination and an increase in self-esteem. In other randomized controlled studies conducted by Jelinek and colleagues, at the end of Metacognitive Training for Depression and at 6-month follow-up, it was determined that there was more improvement in depressive symptoms and a decrease in dysfunctional metacognitive beliefs. In secondary analyses conducted 3.5 years later, it was found that positive effects were still seen in the groups where Metacognitive Training for Depression was applied. The adaptation study of the Metacognitive Training for Depression program to Turkish culture was conducted by Okyay and Taş (2017) and the results of the study show that there is a significant difference in the data of Rumi Positive \& Negative Scales, Ruminative Reactions Scale and Self-Efficacy Scale in depression patients who were administered this program. In another study (2022), after Metacognitive Training for Depression, there was a decrease in the Beck Depression Scale and Cognitive Distortions Scale scores, depression and cognitive distortion levels of patients.

The presentation of the positive effects of Metacognitive Training for Depression with high level of evidence has contributed to the development of the Metacognitive Training for Older Adults (MCT-Silver) program for depression in older adults. Metacognitive Training-Silver focuses on helping individuals move away from thought patterns that feed/support depression and focuses on physical changes that occur during the aging process, coping with loss and adapting to new social roles. Metacognitive Training-Silver addresses how to identify and reinterpret values in life for individuals aged 60 and over and how to move towards accepting situations that cannot be prevented/changed. In the first pilot study (2018) of the Metacognitive Training-Silver program, a significant reduction in depressive symptoms and dysfunctional attitudes was found. Therefore, more studies are needed to prove the effectiveness of the Metacognitive Training-Silver program.

The Metacognitive Training-Silver program has not yet been adapted to Turkish culture and studies are needed to prove its effectiveness in Turkey. In this direction, a randomized controlled trial is planned to evaluate the effectiveness of the Metacognitive Training-Silver program in older adults diagnosed with depression.