In a world where the population is aging, strategies are required that promote physical, social and mental health in these age groups. Depression associated with biological aging is evidenced by clinical findings and biological markers in the course of the disease (such is the case of the GDF-15). The presence of mental health disorders, such as depression, favors the risk of premature mortality (even 25 years less than the general population, even controlling for the suicide variable.

In addition, older adult patients with depression have a higher risk of presenting chronic diseases, immunological alterations, and neurocognitive disorders , favoring accelerated aging that contributes to a reduction in their intrinsic and functional capacities. (51) .

GDF -15 has been proposed as a pro-aging protein , specifically promoted by mitochondrial dysfunction, which in turn leads to accelerated aging through oxidative stress.

In addition, considering that mental health requires care through therapies with the necessary scientific evidence to have an impact on the mental and physical health of older adults, therefore , Acceptance and Commitment Therapy is proposed as a way to lead to healthy aging that promotes less oxidative stress derived from the same depression. Therefore, the purpose of this study is focused on demonstrating the efficacy of acceptance and commitment therapy implemented for twelve weeks in a group of older adults with and without depression, and evaluating it considering the serum levels of GDF- 15 .

Research question:

What is the efficacy of the implementation of Acceptance and Commitment Therapy in a group modality for twelve weeks on the serum levels of GDF-15 in older adults with and without depression?

General objective:

To determine the effectiveness of the implementation of Acceptance and Commitment Therapy in a group mode for twelve weeks on the serum levels of GDF-15 in older adults with and without depression .

Specific objectives:

• To determine the severity of depressive symptoms in the elderly participants.
• To assess the serum levels of GDF-15 in the elderly participants.
• To compare the serum levels of GDF-15 before and after the implementation of Acceptance and Commitment Therapy for twelve weeks in older adults with and without depression.
• To compare the depressive symptoms before and after the implementation of the Acceptance and Commitment Therapy and the control group for twelve weeks.
• Evaluate the adherence to the interventions carried out on the study participants.
• To establish the influence of age, sex, comorbidities and socioeconomic level on the efficacy of acceptance and commitment therapy and the control group in the participants.

Study hypothesis:

Older adults with depression show a greater decrease in serum GDF-15 levels after the implementation of Acceptance and Commitment Therapy in a group mode when compared to the group without depression for twelve weeks.

Type of research and variables:

Study Design: Non-randomized intervention study.

• For ethical reasons, it is methodologically inappropriate to randomize the study groups, so the protocol will adhere to the TREND guidelines (Transparent Reports of Non-randomized Evaluations [for its acronym in English: Transparent reporting of reviews with nonrandomized Designs ]), which share several criteria with CONSORTs.

Inclusion Criteria:

• Adults over 60 years of age of any gender with at least nine years of studies.
• People belonging to the group of Retirees and Pensioners of the University of Colima AC
• People who wish to voluntarily participate in the study.
• People with and without depression.

Exclusion Criteria:

• People who are undergoing psychological treatment or who in the last 12 months have undergone some psychological therapy.
• People under drug treatment for depression.
• People with a score of less than 23 points in the assessment of the cognitive state by the Minimental .
• People with medical diagnosis of neurocognitive diseases.

For ethical reasons, it is methodologically inappropriate to randomize the study groups, so the protocol will adhere to the TREND guidelines (Transparent Reports of Non-randomized Evaluations [for its acronym in English: Transparent reporting of reviews with nonrandomized Designs ]), which share several criteria with CONSORTs