Understanding canine aggression: Neurobiological insights for a complex behavior

The relationship between humans and dogs, as the first domesticated animals, exemplifies a significant aspect of human-animal interaction. During domestication, dogs have undergone behavioral changes to establish closer bonds with humans. However, certain dogs face challenges in fully adapting to their new environment, leading to behavioral disorders such as aggression. One of the most prevalent and dangerous behavioral problems in dogs is aggression, which poses risks to both humans and the dogs themselves, sometimes resulting in euthanasia. Canine aggression can arise from various medical and non-medical factors, including physical problems, endocrine system disorders, infectious diseases, central nervous system diseases, hereditary conditions, as well as racial or personal differences. Evaluating aggression based solely on species, breed, and sex characteristics is insufficient. Accurate diagnosis of aggressive behavior requires integrating findings from diverse diagnostic methods, including serum biochemistry, hormone analysis, urinalysis, electroencephalography, radiography, magnetic resonance tests, and behavioral assessments. However, to gain a comprehensive understanding of canine aggression, it is essential to consider the underlying pathophysiological processes and neurobiology. The management of aggressive behavior in dogs necessitates the implementation of diverse treatment strategies aimed at preventing the manifestation of undesirable behaviors. Within the realm of medical interventions, neutering and pharmacotherapy have emerged as prominent approaches. Neutering has shown effectiveness in mitigating aggression among dogs exhibiting aggressive tendencies. On the other hand, pharmacotherapy involves the utilization of complementary and suppressive pharmacological agents that target primary and intermediate components within the mechanisms underlying aggression. These components encompass neurotransmitter/neuromodulator substances, peptides, enzymes, and hormones, all of which contribute to the pathophysiological processes of aggression. Through the modulation of these factors, pharmacotherapy seeks to offer a comprehensive treatment approach for addressing aggressive behavior in dogs. This review aims to investigate the neurobiological basis of aggression in dogs, considering the underlying pathophysiological processes and the role of neurotransmitter/neuromodulator substances, neuropeptides, peptides, enzyme systems, and hormones. Accurate diagnosis and understanding of canine aggression are crucial for the development of effective medical and alternative treatment methods.