Background <p>Most informal caregivers of persons with dementia suffer from symptoms of anxiety and depression, but there is still a lack of clear optimal intervention targets for this group. This study aims to explore the interrelationships between symptoms of anxiety and depression among informal caregivers of persons with dementia, identifying key symptoms to provide a scientific basis for developing precise mental health prevention and intervention strategies.</p> Methods <p>This study utilized a cross-sectional design. The Generalized Anxiety Disorder-7 and the Patient Health Questionnaire-9 were used to assess symptoms of anxiety and depression among informal caregivers. Latent profile analysis was used to identify subgroups of informal caregivers of persons with dementia with anxiety and depression profiles. We constructed anxiety-depression network structures and identified the core symptoms and bridging symptoms for each subgroup. Computer-simulated analysis was conducted to modulate each symptom to assess its impact on overall network connectivity.</p> Results <p>A total of 246 pairs of persons with dementia and informal caregivers were recruited from November 2024 to June 2025. Informal caregivers of persons with dementia were divided into two subgroups including the low anxiety-low depression group (66.26%) and the high anxiety-high depression group (33.74%). “Low mood” represented the core and bridging symptom of the low anxiety-low depression group and “uncontrollable worrying” of the high anxiety-high depression group. Computer simulation intervention suggested that in the low anxiety-low depression group, “easily irritable” and “feeling tense” were respectively identified as the targeted intervention symptoms that may alleviate and aggravate the symptoms of anxiety and depression. While in the high anxiety-high depression group, “uncontrollable worrying” and “loss of pleasure” were respectively identified as the targeted intervention symptoms that may alleviate and aggravate the symptoms of anxiety and depression.</p> Conclusion <p>Our findings highlight the crucial role of low mood and uncontrollable worrying in the network of symptoms of anxiety and depression among informal caregivers of persons with dementia. Based on simulated intervention results, it has certain reference significance for future research to develop intervention strategies for easily irritable and uncontrollable worrying and prevent symptoms of feeling tense and loss of pleasure to improve informal caregivers’ mental health.</p>