A relationship between bladder infections and enuresis has been long established and was further confirmed by Hansson in 1992. However, urinary tract obstruction is highly debated in the literature as a cause, warranting caution before recommending unnecessary surgery, especially considering that urethral dilatation and/or bladder neck repair do not appear to be effective treatments for enuresis. Circadian rhythmicity and its role in the ability for children to concentrate their urine has also been implicated. A substance called plasma arginine vasopressin (AVP) has been found to be decreased in children with enuresis and may be able to explain the ability for desmopressin (DDAVP) to help resolve enuresis. Certain medications
are also known to cause secondary enuresis and include lithium, valproic acid, clozapine, and theophylline.

Developmental delay has been found to occur twice as often in children with enuresis as in those without enuresis in an early study by Essen and Peckham. Enuresis correlates with multiple maturational delays in the areas of language, speech, motor skills, and social development. Furthermore, delayed maturation of central nervous system functioning has been considered as a possible contributing factor after a study by Mimouni and colleagues in 1985 showed that children with enuresis lagged behind control children in bone age and height. Delayed maturation likely also contributes to the manifestation of enuresis in conjunction with behavioral disturbances. The association of enuresis with behavioral disturbance is higher in secondary enuresis and enuresis that persists into adolescence. Lastly, among adolescents, late sexual maturation has been associated with enuresis.

The rate of psychiatric disorders is higher in children with enuresis compared to children without enuresis; however, most children with enuresis do not show symptoms of emotional or behavioral difficulties. A recent prospective study by Zink and colleagues in 2008 found that children with voiding postponement had the highest rates of psychiatric comorbidity, while children with monosymptomatic nocturnal enuresis had the lowest rates of psychiatric comorbidity. Psychiatric disorders can occur coincidentally with enuresis or even as a result of enuresis. It is important to remember that for a small subgroup of children, however, enuresis does have a psychological etiology, which is most frequently associated with secondary enuresis that develops after a stressor. Secondary enuresis has also been reported after sexual molestation. When psychological factors are related to primary enuresis, it is typically when there has been considerable disorganization or neglect within the family so that appropriate efforts at toilet training were not made.

Genetics plays a large role in the transmission of primary enuresis across generations. The chromosomes that have been identified include 13q, 12q, 8, and 22. In families of enuretic children, one third of fathers and one fifth of mothers were themselves enuretic as children.
A penetrance above 90% has been found in some families with an autosomal dominant mode of transmission.

Although a sleep disorder cannot be identified as a major etiologic factor in enuresis, sleep states have long been studied in terms of their relationship to enuretic episodes. Roberts found that these episodes occur in each sleep stage, in proportion to the amount of time spent in that stage. Children with primary enuresis also appear to be more difficult to arouse during sleep compared to control subjects. Enuresis has also been reported in association with specific sleep disorders, including narcolepsy and sleep apnea syndrome. However, no specific sleep state or disorder has been found to be causal in enuresis.

Physiologic factors must be considered in children with encopresis. Abnormal anorectal dynamics can contribute to problems with encopresis. These include a failure of the external sphincter to relax in conjunction with rectal contraction waves, a weak internal sphincter, or abdominal straining. Anatomic causes include anterior location of the anus, anal fissure, anal stenosis, and/or anal atresia. Furthermore, a correlation has been found between children who were constipated in the first year of life and the development of subsequent encopresis. On the other hand, encopresis also arises after a bout with diarrhea or acute constipation. Constipation can cause painful defecation and can lead to anal fissures, both of which can cause children to withhold to prevent further pain, leading to chronic constipation.

Hormonal influences have also been postulated in the etiology of encopresis. Stern and colleagues speculated that postprandial levels of pancreatic polypeptide peaked earlier and remained higher, while the motilin response was lower in children with encopresis. However, the authors could not conclude whether these findings were the result or the cause of chronic constipation.

Developmental delay associated with encopresis has been shown specifically in patients with lower intellectual abilities. Fragile X syndrome and other forms of mental retardation, cerebral palsy, and hypotonia can increase the risk of fecal incontinence.

Parental attitudes toward toilet training play a key role in the development of fecal continence. Parents must be attuned to their child’s signals and be able to remain calm when introducing their child to the toilet. They need to be encouraging and give praise when children are able to defecate in the toilet. Conversely, parents should avoid punishing children when they fail and not try to coerce children to use the toilet. Parents who are experiencing depression or other psychiatric disorders may not be fully emotionally available to assist in this process. Toilet training for fecal continence also involves a great deal of learning on the children’s part. They must learn when and where it is appropriate to defecate, how to sense rectal fullness, and the process of withholding until the appropriate place to defecate is found. They also must learn to get into the right posture, relax their sphincters, and increase intra-abdominal pressure.

Children who have been sexually abused may present with fecal incontinence. Signs and symptoms that may accompany this can include sexual acting out or other regressive behaviors. Additional psychiatric disorders and/or symptoms that have been associated with encopresis
include enuresis, oppositional defiant disorder, tantrums, school refusal, and fire setting. However, the degree of association between these symptoms has not yet been established, and therefore, it is undetermined whether psychological problems are causal, associated, or secondary to encopresis.