Developmental psychology
Attachment theory, originally developed by John Bowlby, focuses on the importance of open, intimate, emotionally meaningful relationships. Attachment is described as a biological system or powerful survival impulse that evolved to ensure the survival of the infant. A child who is threatened or stressed will move toward caregivers who create a sense of physical, emotional and psychological safety for the individual. Attachment feeds on body contact and familiarity. Later Mary Ainsworth developed the Strange Situation protocol and the concept of the secure base.
Attachment and Health
According to attachment theory people with insecure attachment have less effective strategies for dealing with negative emotions compared to people with secure attachment. One way in which insecurely individuals may try to regulate their distress is by using strategies or behaviours that are attractive for their short term relief but may have deleterious risks over years like eating, drug use or risky sex. 
In a survey of 356 primary care patients in Toronto, rates of smoking, harmful drinking and obesity, were all found to be highest in those with the most severe anxious and avoidant attachment. Both attachment anxiety and attachment avoidance have been linked in separate studies to increasing the risk of eating disorders and substance use in adolescents.