Exploring the Role of Cognitive Reserve and Human–Animal Interaction in Late-Life Depression: A Moderation Analysis

<b>Background/Objectives:</b> Depression impairs the quality of life in older adults and represents a significant public health issue. Cognitive reserve may act as a protective factor against depressive symptoms in older adults. Additionally, interaction with pets may serve as another potential protective factor against these symptoms. Thus, this study aimed to evaluate whether higher cognitive reserve could predict a reduction in depressive symptoms in older adults and to investigate the moderating role of pet companionship in this relationship. <b>Methods:</b> The following instruments were used: a Sociodemographic Data Sheet, the Modified Telephone Interview for Cognitive Status (TICS-M), the Cognitive Reserve Index Questionnaire (CRIq), and the Geriatric Depression Scale (GDS-15). Data were collected via video calls through WhatsApp and analyzed using a moderation analysis with PROCESS for SPSS. <b>Results:</b> The final sample consisted of 215 older adults with a mean age of 69.13 years (SD = 6.89). Among the participants, 53% owned pets and 47% did not. The overall model revealed a significant association between the predictor variables and the outcome (F(3, 211) = 4.24, <i>p</i> < 0.01). For the group without pets, the effect was not significant (β = -0.1082, <i>p</i> = 0.2916), but for the group with pets, the effect was substantial and negative on the GDS (β = -0.1936, <i>p</i> < 0.05). <b>Conclusions:</b> We concluded that the relationship between cognitive reserve and depressive symptoms is moderated by the presence of pets in individuals' lives. These findings highlight the role of pets in protecting against depressive symptoms in older adults. Future studies should explore this relationship with more diverse samples.