John Bowlby's attachment theory proposed that the quality of early caregiving shapes internal working models, mental representations of self and other that guide expectations and behaviours in subsequent relationships throughout life. Mary Ainsworth's Strange Situation experiments identified three primary attachment patterns in infants: secure, anxious, and avoidant. A fourth, disorganised, was identified later. What was not known when Bowlby and Ainsworth developed the theory is that these early relationship templates continue to have direct physiological effects in adulthood, influencing the stress response, inflammatory activity, and health-related behaviour.
Secure Attachment and Health
Securely attached adults, those who expect relationships to be reliable sources of support and comfort, show the most adaptive physiological responses to stress. They show smaller cortisol responses to laboratory stressors, return to baseline more quickly after activation, and show lower resting levels of inflammatory markers. They are more likely to seek medical care when needed, more likely to adhere to treatment recommendations, and less likely to use avoidance or rumination as coping strategies. Secure attachment is associated with better immune function, lower cardiovascular risk, and longer telomere length.
Anxious Attachment and Health
Anxiously attached adults, characterised by hyperactivation of the attachment system and preoccupation with relationship security, show elevated baseline cortisol, heightened cardiovascular reactivity to interpersonal stressors, and higher levels of inflammatory markers. They tend to amplify physical symptoms and are more likely to catastrophise health threats. Paradoxically, their elevated health anxiety does not translate to better health behaviour; the same catastrophising that makes them worry more about health threats also makes them more likely to avoid definitive medical investigation.
Avoidant Attachment and Health
Avoidantly attached adults, characterised by deactivation of the attachment system and apparent self-sufficiency, present a more subtle pattern. They report low distress and low relationship dependence, but physiological measures tell a different story: when engaging in tasks designed to activate the attachment system, avoidantly attached adults show elevated sympathetic arousal despite their behavioural appearance of calm. Research by Paula Pietromonaco and colleagues found that avoidant attachment was associated with elevated ambulatory blood pressure during interpersonal conflict, despite lower self-reported distress.
Attachment Can Change
The early view that attachment patterns were fixed by age three is not supported by the current evidence. Longitudinal studies show meaningful movement across attachment categories across the lifespan, particularly following significant positive or negative relationship experiences and in response to psychotherapy. Earned security, the development of secure attachment patterns in adulthood following insecure early experience, is associated with health outcomes comparable to those of people who were securely attached from childhood. The plasticity of the attachment system is good news for anyone whose early relational experience was difficult.