Background
The origins of separation anxiety disorder stem from attachment theory which has roots in the attachment theories both of Sigmund Freud and John Bowlby. Freuds attachment theory, which has similarities to learning theory, proposes that infants have instinctual impulses, and when these impulses go unnoticed, it traumatizes the infant. The infant then learns that when their mother is absent, this will be followed by a distressing lack of gratification, thus making the mothers absence a conditioned stimulus that triggers anxiety in the infant who then expects their needs to be ignored. The result of this association is that the child becomes fearful of all situations that include distance from their caregiver. John Bowlbys attachment theory also contributed to the thinking process surrounding separation anxiety disorder. His theory is a framework in which to contextualize the relationships that humans form with one another. Bowlby suggests that infants are instinctively motivated to seek proximity with a familiar caregiver, especially when they are alarmed, and they expect that in these moments they will be met with emotional support and protection. He poses that all infants become attached to their caregivers, however, there are individual differences in the way that these attachments develop. There are 4 main attachment styles according to Bowlby; secure attachment, anxious-avoidant attachment, disorganized attachment, and anxious-ambivalent attachment. Anxious-ambivalent attachment is most relevant here because its description, when an infant feels extreme distress and anxiety when their caregiver is absent and does not feel reassured when they return, is very similar to SAD.
In humans
In humans, enteroliths are rare and may be difficult to distinguish from gall stones. Their chemical composition is diverse, and rarely can a nidus be found. A differential diagnosis of an enterolith requires the enterolith, a normal gallbladder, and a diverticulum.An enterolith typically forms within a diverticulum. An enterolith formed in a Meckels diverticulum sometimes is known as a Meckels enterolith. Improper use of magnesium oxide as a long-term laxative has been reported to cause enteroliths and/or medication bezoars.Most enteroliths are not apparent and cause no complications. However, any complications that do occur are likely to be severe. Of these, bowel obstruction is most common, followed by ileus and perforation. Bowel obstruction and ileus typically occur when a large enterolith is expelled from a diverticulum into the lumen. Perforation typically occurs within the diverticulum.On plain X-rays,the visibility of the enterolith depends on its calcium content. Calcium-rich stones usually demonstrate a radiodense rim and a relatively radioluscent core. Choleic acid stones are almost always radiolucent. They sometimes can be visualized on CT scans without contrast;  presence of contrast in the lumen may reveal the enterolith as a void. Most often, they are visualized using ultrasound. Although recent surveys of enterolith composition are lacking, one early review notes struvite (as in equines), calcium phosphate, and calcium carbonate and reports choleic acid. Deoxycholic acid and cholic acid have also been reported. Treatment
In simple cases of obstruction, where there are no complications, a variety of non-surgical and surgical techniques are used to remove the enterolith.