Attachment theory provides numerous implications for mental health and individual functioning throughout the lifespan. Attachment styles, formed based on early interactions with a caregiver, play a crucial role in emotional regulation, relational satisfaction, and psychological well-being. Childhood experiences become the foundation for the development of internal models of self, the world, and others, influencing attachment patterns in adulthood. These patterns are significant for later relationships, especially romantic ones, mental health, and the development of psychopathology. If the primary caregiver responds consistently, supports, and comforts the child, the child will be inclined to cooperate, seek closeness, and feel loved and safe. Such a child will develop a secure attachment, viewing the caregiver as a secure base and a refuge from the unpredictable world. Individuals who formed a secure attachment style in childhood tend to create stable and mature relationships, exhibit greater psychological resilience, and are less likely to struggle with mental health issues. Conversely, if the caregiver is unresponsive or lacks sensitivity, the child may develop an insecure attachment style, characterized by heightened anxiety or avoidance. Attachment-related anxiety is associated with a persistent state of heightened vigilance, as individuals remain on alert, anticipating potential separation from their parents. Avoidant attachment is marked by a tendency to maintain emotional distance, reluctance to rely on others, and a lack of seeking comfort and support from caregivers. An insecure attachment style negatively impacts romantic relationships. Moreover, individuals characterized by attachment anxiety or avoidance are more prone to mental health disorders. Attachment theory provides a crucial framework for understanding the complex links between early relational experiences and mental health. Poor relationship quality, complex PTSD, depression, personality disorders—particularly antisocial and borderline—have their roots in early maladaptive relationships between the child and caregiver and may be related to interpersonal trauma. Secure attachment acts as a protective factor against psychopathologies, promoting emotional stability and healthy social functioning.