Pervasive refusal syndrome is for the most part frequently seen in girls and less so in boys. The average age of onset is between the ages of 7 and 15. Affected children are usually high achievers with high self-expectations, fears of failure, and difficulty dealing with failure to achieve personal standards. The onset of PRS is usually acute.

There are a number of factors that could potentially contribute to the development of feeding and eating disorders of infancy or early childhood. These factors include:

- Physiological – a chemical imbalance effecting the child's appetite could cause a feeding or eating disorder.

- Developmental – developmental abnormalities in oral-sensory, oral-motor, and swallowing can impact the child's eating ability and elicit a feeding or eating disorder.

- Environmental – simple issues such as inconsistent meal times can cause a feeding or eating disorder. Giving the child food that they are not developmentally acquired for can also cause these disorders. Family dysfunction and sociocultural issues could also play a role in feeding or eating disorders.

- Relational – when the child is not securely attached to the mother, it can cause feeding interactions to become disturbed or unnatural. Other factors, such as parental emotional unavailability and parental eating disorders, can cause feeding and eating disorders in their children.

- Psychological and behavioral – these factors include one involving the child's temperament. Characteristics such as being anxious, impulsive, distracted, or strong-willed personality types are ones that could affect the child's eating and cause a disorder. The individual could have learned to reject food due to a traumatic experience such as choking or being force fed.

Trauma, in general, appears to be an important factor, due to the fact that PRS is also repeatedly seen in refugees and witnesses to violence. The helplessness and hopelessness can transmit from parents to children and from children to parents as they watch one another battling with uncontrollable proceedings. Viral infections are repeatedly seen to be a factor in PRS; many cases are thought to begin with a viral infection. There have been other theories regarding the cause of PRS, for instance, the psychodynamic theory of fatal mothering and a potential neurobiological role of the insula. Von Folsach and Montgomery put forth four essential risk factors: (1) a premorbid personality, (2) a history of child psychiatric problems, (3) parental psychiatric problems and (4) sudden stressful events. PRS children are typically known to be perfectionists, conscientious and high achievers. When these children are put in stressful events that they feel they cannot control, they go into a state of learned helplessness. Previous child psychiatric problems can designate a susceptibility to develop PRS when put in stressful situations, and parental psychiatric problems may influence the parents' capability to support and care for their children.

Physical and emotional changes are often the most indicative symptoms of feeding and eating disorders of infancy or early childhood. The child's growth and development may be delayed due to the lack of necessary nutrients. The child will usually weigh much less than other children. Withdrawal and irritability are often associated with children that are malnourished.

Individuals suffering from Diogenes syndrome generally display signs of collectionism, hoarding, or compulsive disorder. Individuals who have suffered damage to the brain, particularly the frontal lobe, may be at more risk to developing the syndrome. The frontal lobes are of particular interest, because they are known to be involved in higher order cognitive processes, such as reasoning, decision-making and conflict monitoring.

Diogenes Syndrome tends to occur among the elderly. The behavioural patterns that is usually reflected by those living with this disorder are suffering from significant functional problem that is correlated with morbidity and mortality.

As with most mental disorders, BDD's causation is likely intricate, altogether biopsychosocial, through an interaction of multiple factors, including genetic, developmental, psychological, social, and cultural. BDD usually develops during early adolescence, although many patients note earlier trauma, abuse, neglect, teasing, or bullying. Though twin studies on BDD are few, one estimated its heritability at 43%. Yet BDD's causation may also involve introversion, negative body image, perfectionism, heightened aesthetic sensitivity, and childhood abuse and neglect. Media influence has also been identified as a factor causing poor body image.

Diogenes syndrome is a disorder that involves hoarding of rubbish and severe self-neglect. In addition, the syndrome is characterized by domestic squalor, syllogomania, social alienation, and refusal of help. It has been shown that the syndrome is caused as a reaction to stress that was experienced by the patient. The time span in which the syndrome develops is undefined, though it is most accurately distinguished as a reaction to stress that occurs late in life.

In most instances, patients were observed to have an abnormal possessiveness and patterns of compilation in a disordered manner. These symptoms suggest damages on the prefrontal areas of the brain, due to its relation to decision making. Although in contrast, there have been some cases where the hoarded objects were arranged in a methodical manner, which may suggest a cause other than brain damage.

Although most patients have been observed to come from homes with poor conditions, and many had been faced with poverty for a long period of time, these similarities are not considered as a definite cause to the syndrome. Research showed that some of the participants with the condition had solid family backgrounds as well successful professional lives. Half of the patients were of higher intelligence level. This indicates the "Diogenes syndrome" does not exclusively affect those experiencing poverty or those who had traumatic childhood experiences.

The severe neglect that they bring on themselves usually results in physical collapse or mental breakdown. Most individuals who suffer from the syndrome do not get identified until they face this stage of collapse, due to their predilection to refuse help from others.

The patients are generally highly intelligent, and the personality traits that can be seen frequently in patients diagnosed with Diogenes syndrome are aggressiveness, stubbornness, suspicion of others, unpredictable mood swings, emotional instability and deformed perception of reality. Secondary DS is related to mental disorders. The direct relation of the patients' personalities to the syndrome is unclear, though the similarities in character suggest potential avenues for investigation.

Although more research is needed to determine the multiple pathways to complicated grief disorder, preexisting conditions (such as major depression, PTSD, and sleep disorders) are thought to exacerbate the interruption of the natural healing process.

There are some known predictive characteristics for CGD. An individual is at increased risk for CGD if they are:

- Female

- Pessimistic

- Previously diagnosed with a mood disorder

- Low self-reported social support

- An insecure attachment

- High stress

- A positive caregiving experience and dependency on the deceased

- Have had a early pregnancy loss (miscarriage)

Untreated CGD has clinically significant consequences. A high level of impairment can be pervasive, including destructive thoughts and behaviors (such as substance abuse). CGD may worsen the course of preexisting disorders and contribute to the development of new ones.

Spoiling in early childhood tends to create characteristic reactions that persist, fixed, into later life. These can cause significant social problems. Spoiled children may have difficulty coping with situations such as teachers scolding them or refusing to grant extensions on homework assignments, playmates refusing to allow them to play with their toys and playmates refusing playdates with them, a loss in friends, failure in employment, and failure with personal relationships. As adults, spoiled children may experience problems with anger management, professionalism, and personal relationships; a link with adult psychopathy has been observed.

Similar to adult personality disorders there are multiple causes and causal interactions for personality development disorders. In clinical practice it is important to view the disorder multi-perspectively and from an individual perspective. Biological and neurological causes need to be observed just as much as psychosocial factors. Looking at the disorder from only one perspective (e.g. (s)he had a bad childhood) often results in ignorance of important other factors or causal interactions. This might be one of the main reasons why traditional treatment methods often fail with these disorders. Only a multi-perspective view can provide for a multi-dimensional treatment approach which seems to be the key for these disorders.

The diagnosis personality development disorder should only be given carefully and after a longer period of evaluation. Also a thorough diagnostic evaluation is necessary. Parents should be questioned separately and together with the child or adolescent to evaluate the severity and duration of the problems. In addition standardized personality tests might be helpful. It is also useful to ask the family what treatment approaches they have already tried so far without success.

Pathological demand avoidance (PDA) is a proposed subtype of autism characterized by an avoidance of demand-framed requests by an individual. It was proposed in 1980 by the UK child psychologist Elizabeth Newson. The Elizabeth Newson Centre in Nottingham, England carries out assessments for the NHS, local authorities and private patients around autism spectrum disorder, which include, but are not exclusively PDA.

PDA behaviours are consistent with autism, but have differences from other autism subtypes diagnoses. It is not recognised by either the DSM-5 or the .

Alfred Adler (1870–1937) believed that "only children" were likely to experience a variety of problems from their situation. Adler theorized that because only children have no rivals for their parents' affection, they will become pampered and spoiled, particularly by their mother. He suggested that this could later cause interpersonal difficulties if the person is not universally liked and admired.

A 1987 quantitative review of 141 studies on 16 different personality traits contradicted Adler's theory. This research found no evidence of any "spoilage" or other pattern of maladjustment in only children. The major finding was that only children are not very different from children with siblings. The main exception to this was the finding that only children are generally higher in achievement motivation. A second analysis revealed that only children, first-borns, and children with only one sibling score higher on tests of verbal ability than later-borns and children with multiple siblings.

Factors that can cause reluctance to attend school can be divided into four categories. These categories have been developed based on studies in the United States under the leadership of Professor Christopher Kearney. Some students may be affected by several factors at once.

- The child might want to be free.

- The child possibly wants to avoid school-related issues and situations that cause them to experience unpleasant feelings, such as anxiety, depression, or psychosomatic symptoms. The reluctance to attend school is one symptom that can indicate the presence of a larger issue, such as anxiety disorder, depression, learning disability, sleep disorder, separation anxiety or panic disorder.

- The child may want to avoid tests, presentations, group work, specific lessons, or interaction with other children. The child should be assessed for learning disabilities if academic performance is average or low.

- The child may want attention from significant people outside of school, such as parents or older acquaintances.

- The child possibly wants to do something more enjoyable outside of school, like practice hobbies, play computer games, watch movies, play with friends such as riding bikes, etc., or learn autodidactictally.

Other factors can be:

- Anxiety about academic achievement and being tested can arise on the basis of inflated claims by teachers and/or parents, but also unrealistic ambitions of the upset child themselves.

- School refusal may arise as a response to bullying or peer rejection.

- Shyness or a social phobia can contribute to school refusal.

- The child might worry about parents or siblings, for instance, a parent with substance abuse, or a parent who physically abuses other family members.

- Some students may refuse to go to school due to anxiety or fears of emergency drills, such as fire, lockdown, and tornado drills.

Traumatic grief or complicated mourning are conditions where both trauma and grief coincide. There are conceptual links between trauma and bereavement since loss of a loved one is inherently traumatic. If a traumatic event was life-threatening, but did not result in death, then it is more likely that the survivor will experience post-traumatic stress symptoms. If a person dies, and the survivor was close to the person who died, then it is more likely that symptoms of grief will also develop. When the death is of a loved one, and was sudden or violent, then both symptoms often coincide. This is likely in children exposed to community violence.

For C-PTSD to manifest, the violence would occur under conditions of captivity, loss of control and disempowerment, coinciding with the death of a friend or loved one in life-threatening circumstances. This again is most likely for children and stepchildren who experience prolonged domestic or chronic community violence that ultimately results in the death of friends and loved ones. The phenomenon of the increased risk of violence and death of stepchildren is referred to as the Cinderella effect.

Neurodevelopmental disorders are in their multitude associated with widely varying degrees of difficulty, depending on which there are different degrees of mental, emotional, physical, and economic consequences for individuals, and in turn families, groups and society.

Approximately 1 to 5% of school-aged children have school refusal, though it is most common in 5- and 6-year olds and in 10- and 11-year olds, it occurs more frequently during major changes in a child’s life, such as entrance to kindergarten, changing from elementary to middle school, or changing from middle to high school. The problem may start following vacations, school holidays, summer vacation, or brief illness, after the child has been home for some time, and usually ends prior to vacations, school holidays, or summer vacation, before the child will be out of school for some time. School refusal can also occur after a stressful event, such as moving to a new house, or the death of a pet or relative.

The rate is similar within both genders, and although it is significantly more prevalent in some urban areas, there are no known socioeconomic differences.

Brain trauma in the developing human is a common cause (over 400,000 injuries per year in the US alone, without clear information as to how many produce developmental sequellae) of neurodevelopmental syndromes. It may be subdivided into two major categories, congenital injury (including injury resulting from otherwise uncomplicated premature birth) and injury occurring in infancy or childhood. Common causes of congenital injury are asphyxia (obstruction of the trachea), hypoxia (lack of oxygen to the brain) and the mechanical trauma of the birth process itself.

All of the causes of childhood disintegrative disorder are still unknown. Sometimes CDD surfaces abruptly within days or weeks, while in other cases it develops over a longer period of time. A Mayo Clinic report indicates: "Comprehensive medical and neurological examinations in children diagnosed with childhood disintegrative disorder seldom uncover an underlying medical or neurological cause. Although the occurrence of epilepsy is higher in children with childhood disintegrative disorder, experts don't know whether epilepsy plays a role in causing the disorder."

CDD, especially in cases of later age of onset, has also been associated with certain other conditions, particularly the following:

- Lipid storage diseases: In this condition, a toxic buildup of excess fats (lipids) takes place in the brain and nervous system.

- Subacute sclerosing panencephalitis: Chronic infection of the brain by a form of the measles virus causes subacute sclerosing panencephalitis. This condition leads to brain inflammation and the death of nerve cells.

- Tuberous sclerosis (TSC): TSC is a genetic disorder. In this disorder, tumors may grow in the brain and other vital organs like kidneys, heart, eyes, lungs, and skin. In this condition, noncancerous (benign) tumors, hamartomas, grow in the brain.

- Leukodystrophy: In this condition, the myelin sheath does not develop in a normal way causing white matter in the brain to disintegrate.

A personality development disorder is an inflexible and pervasive pattern of inner experience and behavior in children and adolescents, that markedly deviates from the expectations of the individual's culture. Personality development disorder is not recognized as a mental disorder in any of the medical manuals, such as the ICD-10 or the DSM-IV, neither is it part of the proposed revision of this manual, the DSM-5. DSM-IV allows the diagnosis of personality disorders in children and adolescents only as an exception.

This diagnosis is currently proposed by a few authors in Germany. The term personality "development" disorder is used to emphasize the changes in personality development which might still take place and the open outcome during development. Personality development disorder is considered to be a childhood risk factor or early stage of a later personality disorder in adulthood.

Adults usually show personality patterns over a long duration of time. Children and adolescents however still show marked changes in personality development. Some of these children and adolescents have a hard time developing their personalities in an ordinary way. DSM-IV states, for example, that children and adolescents are at higher risk to develop an antisocial personality disorder if they showed signs of conduct disorder and attention deficit disorder before the age of 10. This led Adam & Breithaupt-Peters (2010) to the idea that these children and adolescents need to be looked at more carefully. The therapy which these children and adolescents need might be more intense and maybe even different from looking at the disorders traditionally. The concept of personality development disorders also focuses on the severity of the disorder and the poor prognosis. An early diagnosis might help to get the right treatment at an early stage and thus might help to prevent a personality disorder outcome in adulthood.

The IDEA requires that a student must exhibit one or more of the following characteristics over a long duration, and to a marked degree that adversely affects their educational performance, to receive an EBD classification:

- Difficulty to learn that cannot be explained by intellectual, sensory, or health factors.

- Difficulty to build or maintain satisfactory interpersonal relationships with peers and teachers.

- Inappropriate types of behavior (acting out against self or others) or feelings (expresses the need to harm self or others, low self-worth, etc.) under normal circumstances.

- A general pervasive mood of unhappiness or depression.

- A tendency to develop physical symptoms or fears associated with personal or school problems.

The term "EBD" includes students diagnosed with schizophrenia, but does not apply to students who are "socially maladjusted", unless it is determined that they also meet the criteria for an EBD classification.

Emotional and behavioral disorders (EBD; sometimes called emotional disturbance or serious emotional disturbance) refer to a disability classification used in educational settings that allows educational institutions to provide special education and related services to students that have poor social or academic adjustment that cannot be better explained by biological abnormalities or a developmental disability.

The classification is often given to students that need individualized behavior supports to receive a free and appropriate public education, but would not be eligible for an individualized education program under another disability category of the Individuals with Disabilities Education Act (IDEA).

There are positive and negative consequences of tube feeding. It is important to wean the child as soon as possible. The longer a child will be tube fed the higher the risk of becoming tube dependent.

Positive consequences:

- establishing life-supporting functions

- improving quality of life after severe medical conditions

- simple control of food intake and positive effect on growth

Negative consequences:

- excessive vomiting, retching and gagging

- reflux diseases, dislocations of feeding tubes, skin irritationss and skin inflammations

- reduced development of oral autonomy, lack of learning to eat autonomously

- impairment in speech, social and motor development

- active food refusal, oral hypersensitivity, food phobia

- strong defense against any contact with fluids, pureed and solid food

- interactive problems and burden to the family, social and financial stress

Estimates of prevalence and gender distribution have varied widely via discrepancies in diagnosis and reporting. In American psychiatry, BDD gained diagnostic criteria in the "DSM-IV", but clinicians' knowledge of it, especially among general practitioners, is constricted. Meanwhile, shame about having the bodily concern, and fear of the stigma of vanity, makes many hide even having the concern.

Via shared symptoms, BDD is commonly misdiagnosed as social-anxiety disorder, obsessive-compulsive disorder, major depressive disorder, or social phobia. Correct diagnosis can depend on specialized questioning and correlation with emotional distress or social dysfunction. Estimates place the Body Dysmorphic Disorder Questionnaire's sensitivity at 100% (0% false negatives) and specificity at 92.5% (7.5% false positives).

Tube dependency develops in children who have the physical ability to ingest and digest food, but failed to be weaned off their temporary intended tube by traditional means and resist/refuse or cannot make the transition to natural oral feeding. It occurs after the phase of critical medical treatment and interventions when the child is expected to resume or start oral intake.

The medical reasons affecting oral explorative behavior, appetite, sucking and swallowing coordination are diverse, including extreme prematurity, neonatal or postnatal operations, intensive care, parenteral feeding, respiratory support and many more.

Many children are tube-fed during the critical age and the stage of developing oral skills. They may have neuromuscular and sensory conditions requiring physio-occupational and speech and language therapy before becoming ready for learning to eat.

The condition also has psychological and social causes. Children who have experienced oral trauma or have been exposed to medicines with bad flavors may become reluctant to repeat oral experiences.

Many children have been on the receiving end of well-intended encouragement and intrusive feeding attempts or even forced feeding, resulting in growing refusal and oppositional behavior. As the phenomenon of tube dependency is hardly recognized as a problem or functional disorder, there is no scientific data on the issue of incidence or risk of development nor epidemiology in countries with a high standard of neonatal medicine and surgery.