Erik Erikson and Daniel Levinson expanded the understanding of adult development. Erikson proposed a life-span model of human development consisting of eight successive psychosocial stages, each associated with an inherent conflict of crisis that the individual must encounter and successfully resolve to proceed with development. Levinson proposed a developmental theory consisting of universal stages of phases that extend from the infancy state to the elderly state, based on biographical interviews of 40 men in America. Both theorists maintained that personality develops in a predetermined order and builds upon each previous stage, and that failure to successfully negotiate a stage can result in a reduced ability to complete further stages and therefore a more unhealthy personality and sense of self. However, Levinson’s theory is age-based rather than event-based, and his model proposed a ‘life sequence’ consisting of a series of alternating stable (structure-building) periods and cross-era transitional (structure-changing) periods, with transitional periods typically lasting 5 years.

Linguistic Development and Risk Factors for Delayed Speech and Language

The development of language skills is an important aspect of a child’s growth. The prelinguistic period, from birth to 12 months, is marked by crying, babbling, and echolalia. From 6 to 12 months, a child responds to their name and can differentiate between angry and friendly tones. By 18 to 24 months, a child can use up to 40-50 words, mainly nouns, and starts to combine words in short phrases. By 36 to 48 months, a child has a vocabulary of 900-1000 words, can use plurals and past tense, and can handle three-word sentences easily.

However, there are risk factors associated with delayed speech and language development. These include a positive family history, male gender, twins, lower maternal education, childhood illness, being born late in the family order, young mother at birth, and low socioeconomic status. of these, a positive family history is considered the most reliable risk factor. It is important to monitor a child’s language development and seek professional help if there are concerns about delayed speech and language.

Developmental Stages

There are four main developmental models that are important to understand: Freud’s theory of psychosexual development, Erikson’s theory of psychosocial development, Piaget’s theory of cognitive development, and Kohlberg’s theory of moral development.

Freud’s theory of psychosexual development includes five stages: oral, anal, phallic, latency, and genital. These stages occur from birth to adulthood and are characterized by different areas of focus and pleasure.

Erikson’s theory of psychosocial development includes eight stages, each with a specific crisis to be resolved. These stages occur from infancy to old age and are focused on developing a sense of self and relationships with others.

Piaget’s theory of cognitive development includes four stages: sensorimotor, preoperational, concrete operational, and formal operational. These stages occur from birth to adulthood and are focused on the development of cognitive abilities such as perception, memory, and problem-solving.

Kohlberg’s theory of moral development includes three stages: preconventional, conventional, and postconventional. These stages occur from childhood to adulthood and are focused on the development of moral reasoning and decision-making.

Understanding these developmental models can help individuals better understand themselves and others, as well as provide insight into how to support healthy development at each stage.

Developmental Stages

There are four main developmental models that are important to understand: Freud’s theory of psychosexual development, Erikson’s theory of psychosocial development, Piaget’s theory of cognitive development, and Kohlberg’s theory of moral development.

Freud’s theory of psychosexual development includes five stages: oral, anal, phallic, latency, and genital. These stages occur from birth to adulthood and are characterized by different areas of focus and pleasure.

Erikson’s theory of psychosocial development includes eight stages, each with a specific crisis to be resolved. These stages occur from infancy to old age and are focused on developing a sense of self and relationships with others.

Piaget’s theory of cognitive development includes four stages: sensorimotor, preoperational, concrete operational, and formal operational. These stages occur from birth to adulthood and are focused on the development of cognitive abilities such as perception, memory, and problem-solving.

Kohlberg’s theory of moral development includes three stages: preconventional, conventional, and postconventional. These stages occur from childhood to adulthood and are focused on the development of moral reasoning and decision-making.

Understanding these developmental models can help individuals better understand themselves and others, as well as provide insight into how to support healthy development at each stage.

Attachment theory is a framework that emphasizes the importance of secure emotional bonds and resources in shaping an individual’s development and behavior. It highlights the significance of early relationships and experiences in shaping one’s sense of security and ability to form healthy relationships later in life.

Turner syndrome often goes undetected due to its subtle symptoms, resulting in delayed diagnosis. However, early identification is crucial as it allows for treatment with growth hormone and oestrogen therapy, which can increase overall height in adulthood. Despite the common belief that women with Turner syndrome are infertile, 2 to 5 percent of patients may experience spontaneous menstruation and childbirth. This could be due to the presence of normal cell populations in the ovaries, resulting from significant 46,XX/45,X mosaicism.

Understanding Turner Syndrome

Turner syndrome is a genetic disorder that affects only females. It occurs when one of the two X chromosomes is missing of partially missing. This happens randomly and does not increase the risk of the condition in future siblings. Although X-inactivation occurs in females, having only one X chromosome can cause issues as not all genes are inactivated in the inactivated X chromosome.

The features of Turner syndrome include short stature, a webbed neck, a broad chest with widely spaced nipples, gonadal dysfunction leading to amenorrhea and infertility, congenital heart disease, and hypothyroidism. Despite these physical characteristics, girls with Turner syndrome typically have normal intelligence, with a mean full-scale IQ of 90. However, they may struggle with nonverbal, social, and psychomotor skills. It is important to understand the symptoms and effects of Turner syndrome to provide appropriate care and support for affected individuals.

Intelligence Test: Raven’s Progressive Matrices

The Raven’s Progressive Matrices (RPM) test is designed to measure general intelligence without the use of verbal language. The test consists of a series of items where the participant is required to identify the missing pattern in a sequence. The difficulty level of the items increases progressively, which demands greater cognitive capacity to encode and analyze the patterns.

There are three versions of the RPM test, each designed for different age groups and abilities. The Coloured Progressive Matrices is intended for younger children and special groups, while the Stanford Progressive Matrices is suitable for individuals aged 6 to 80 years old with average intelligence. The Advanced Progressive Matrices is designed for above-average adolescents and adults.

The three major types of learning are: operant conditioning, classical conditioning, and observational learning. In operant conditioning, an individual’s behavior is instrumental in achieving a desired outcome. In classical conditioning, a neutral stimulus is paired with a stimulus that already evokes a reflex response, eventually leading to the new stimulus evoking a similar response. Observational learning involves learning through the observation of others. Shaping, a part of operant conditioning, involves reinforcing successive approximations to a desired behavior. Extinction, seen in both classical and operant conditioning, involves the observed behavior gradually stopping due to the absence of reinforcement of presentation of the stimulus alone.

If Peter had reached the stage of post-conventional morality, he would have evaluated whether purchasing sports equipment was a cause that aligned with his personal values and beliefs, rather than simply fulfilling a duty because his class was participating in it.

Kohlberg’s Six Stages of Moral Development

Kohlberg’s theory of moral development consists of six stages that can be categorized into three levels. The first level is the preconventional stage, which is characterized by obedience and punishment orientation, where the focus is on the direct consequences of actions and unquestioning deference to power. The second stage is the self-interest orientation, where right behavior is defined purely by what is in the individual’s own interest.

The second level is the conventional stage, which is characterized by interpersonal accord and conformity, where the focus is on how the individual will appear to others. The behavior should accord with a consensus view on what is good. The second stage is the authority and social order obedience driven, where what is lawful is judged to be morally right. Right behavior is dictated by societal rules, and there is a greater respect for social order and the need for laws.

The third level is the postconventional stage, which is characterized by the social contract orientation, where individual rights determine behavior. The individual views laws and rules as flexible tools for improving human purposes. The fourth stage is the universal ethical principles orientation, where the right action is the one that is consistent with abstract reasoning using universal ethical principles.

It is important to note that the age ranges for Kohlberg’s developmental stages are rough guides, and sources vary widely. Kohlberg developed his stage theory following an experiment he conducted on 72 boys aged 10-16. However, the theory is criticized as sexist as it only included boys.

Mahler’s Separation-Individuation theory of child development proposes that personality development occurs in distinct stages. The first stage, the Autistic phase, occurs during the first few weeks of life, where the child is mostly sleeping and cut off from the world. The second stage, the Symbiotic phase, lasts until around six months of age, where the child sees themselves and their mother as a single unit. The third stage, Separation-Individuation, has four subphases. The first subphase, Differentiation, occurs between six to ten months, where the child begins to see themselves as an individual and experiences separation anxiety. The second subphase, Practicing, occurs between ten to sixteen months, where the child explores connections with the external world and people other than the mother. The third subphase, Rapprochement, occurs between sixteen to twenty-four months, where the child struggles to balance their desire for independence and proximity to the mother, often resulting in tantrums and the use of transitional objects. The fourth subphase, Object constancy, occurs between twenty-four to thirty-six months, where the child accepts the idea of object constancy and is more comfortable with the mother being separate for periods of time.

Kohlberg’s Six Stages of Moral Development

Kohlberg’s theory of moral development consists of six stages that can be categorized into three levels. The first level is the preconventional stage, which is characterized by obedience and punishment orientation, where the focus is on the direct consequences of actions and unquestioning deference to power. The second stage is the self-interest orientation, where right behavior is defined purely by what is in the individual’s own interest.

The second level is the conventional stage, which is characterized by interpersonal accord and conformity, where the focus is on how the individual will appear to others. The behavior should accord with a consensus view on what is good. The second stage is the authority and social order obedience driven, where what is lawful is judged to be morally right. Right behavior is dictated by societal rules, and there is a greater respect for social order and the need for laws.

The third level is the postconventional stage, which is characterized by the social contract orientation, where individual rights determine behavior. The individual views laws and rules as flexible tools for improving human purposes. The fourth stage is the universal ethical principles orientation, where the right action is the one that is consistent with abstract reasoning using universal ethical principles.

It is important to note that the age ranges for Kohlberg’s developmental stages are rough guides, and sources vary widely. Kohlberg developed his stage theory following an experiment he conducted on 72 boys aged 10-16. However, the theory is criticized as sexist as it only included boys.

Linguistic Development and Risk Factors for Delayed Speech and Language

The development of language skills is an important aspect of a child’s growth. The prelinguistic period, from birth to 12 months, is marked by crying, babbling, and echolalia. From 6 to 12 months, a child responds to their name and can differentiate between angry and friendly tones. By 18 to 24 months, a child can use up to 40-50 words, mainly nouns, and starts to combine words in short phrases. By 36 to 48 months, a child has a vocabulary of 900-1000 words, can use plurals and past tense, and can handle three-word sentences easily.

However, there are risk factors associated with delayed speech and language development. These include a positive family history, male gender, twins, lower maternal education, childhood illness, being born late in the family order, young mother at birth, and low socioeconomic status. of these, a positive family history is considered the most reliable risk factor. It is important to monitor a child’s language development and seek professional help if there are concerns about delayed speech and language.

Psychosexual Development

The psychosexual theory of development, developed by Freud, outlines a number of stages that individuals go through in their development. These stages are quite complex, but tend to come up in exams. The stages include the oral stage, which occurs from birth to 18 months, where pleasure and needs are explored through sucking, swallowing, and biting. The anal stage occurs from 18 to 36 months, where pleasure and needs are explored through bowel and bladder elimination and retention. The phallic stage occurs from 3 to 5 years, where boys pass through the Oedipal complex and girls the Electra complex. Girls are also said to develop penis envy in this stage. The latency stage occurs from 5 to puberty, where the sexual drive remains latent. Finally, the genital stage occurs from puberty to adulthood, where a person achieves independence from their parents and forms intimate relationships with others.

Sophie has entered the phase of conventional morality where she comprehends that morality is determined by motivation rather than outcomes. However, societal norms still dictate what is considered moral rather than individual beliefs. This is exemplified by the emphasis on everyone in moral reasoning. Additionally, children begin to recognize the significance of portraying themselves as having virtuous intentions.

Starting to sit unsupported at 8 months is considered normal as it falls within the expected range of achieving this milestone by 9 months. However, the other choices suggest a delay in development.

The Emergence of Social Smiling in Infants

Wormann (2014) discusses the emergence of social smiling in infants, which is usually interpreted as the first positive expression directed towards a cause. This occurs when an infant with an initially expressionless face examines the face of another person, and their face and eyes light up while the corners of their mouth pull upward. The age of the first appearance of the social smile varies across cultures, ranging from the fifth to seventh week. Additionally, there are differences in its duration and frequency between the second and seventh month of life. Understanding these milestones is important for a basic understanding of normal child development.

Child Development Milestones:
4 weeks Responds to noise (either by crying, of quieting), follows an object moved in front of eyes
6 weeks Begins social smiling*
3 months Holds head steady on sitting
6 months Rolls from stomach to back, starts babbling
7 months Transfers objects from hand to hand, looks for dropped object
9 months Sits unsupported, begins to crawl
12 months Cruising (walking by holding furniture)
18 months Walks without assistance, speaks about 10-20 words
2 years Runs, climbs up and down stairs alone, makes 2-3 word sentences
3 years Dresses self except for buttons and laces, counts to 10, feeds themself well
4 years Hops on one foot, copies a cross
5 years Copies a triangle, skips

Erik Erikson and Daniel Levinson expanded the understanding of adult development. Erikson proposed a life-span model of human development consisting of eight successive psychosocial stages, each associated with an inherent conflict of crisis that the individual must encounter and successfully resolve to proceed with development. Levinson proposed a developmental theory consisting of universal stages of phases that extend from the infancy state to the elderly state, based on biographical interviews of 40 men in America. Both theorists maintained that personality develops in a predetermined order and builds upon each previous stage, and that failure to successfully negotiate a stage can result in a reduced ability to complete further stages and therefore a more unhealthy personality and sense of self. However, Levinson’s theory is age-based rather than event-based, and his model proposed a ‘life sequence’ consisting of a series of alternating stable (structure-building) periods and cross-era transitional (structure-changing) periods, with transitional periods typically lasting 5 years.

Piaget’s cognitive theory involves the use of existing patterns of knowledge and behavior, known as schemas, through the process of assimilation. However, when faced with new situations, these schemas may need to be modified, which is known as accommodation. The theory is comprised of three main components: schemas, processes that facilitate the transition between stages (equilibrium, assimilation, and accommodation), and four stages of development: sensorimotor (0-2 years), preoperational (2-7 years), concrete operational (7-11 years), and formal operational (11+ years).

Rett Syndrome: A Rare Neurodevelopmental Disorder

Rett syndrome is a neurodevelopmental disorder that is rare, affecting approximately 1 in 10,000 female births. Although it mostly affects females, there have been cases of males with the disorder. While the exact cause of the disorder is not known, it is believed to have a genetic basis, with mutations in the MECP2 gene (Xq28) being associated with the disorder. Monozygotic twins have been found to have complete concordance in cases of Rett syndrome.

The disorder has a unique presentation, with affected children experiencing a normal period of development until 6-18 months. After this period, they begin to develop problems with language, losing previously acquired speech. Purposeful hand movements are replaced with stereotypic movements, such as hand wringing, and ataxia and psychomotor retardation may occur. Other stereotypical movements, such as finger licking of biting and tapping of slapping, may also be seen. Head circumference is normal at birth, but growth begins to decelerate between 6-12 months, resulting in microcephaly. All language skills are lost, both receptive and expressive, and social skills plateau at developmental levels between 6-12 months.

Seizures are associated with Rett syndrome in 75% of those affected, and almost all affected children have abnormal EEG findings. Breathing problems, such as hyperventilation, apnea, and breath holding, are also seen. Children with Rett syndrome may live for well over a decade after the onset of the disorder, but after 10 years, many patients are wheelchair-bound with virtually no language ability. Additional features of the disorder include seizures, breath holding and hyperventilation, sleep difficulties, and issues with locomotion.

The Emergence of Social Smiling in Infants

Wormann (2014) discusses the emergence of social smiling in infants, which is usually interpreted as the first positive expression directed towards a cause. This occurs when an infant with an initially expressionless face examines the face of another person, and their face and eyes light up while the corners of their mouth pull upward. The age of the first appearance of the social smile varies across cultures, ranging from the fifth to seventh week. Additionally, there are differences in its duration and frequency between the second and seventh month of life. Understanding these milestones is important for a basic understanding of normal child development.

Child Development Milestones:
4 weeks Responds to noise (either by crying, of quieting), follows an object moved in front of eyes
6 weeks Begins social smiling*
3 months Holds head steady on sitting
6 months Rolls from stomach to back, starts babbling
7 months Transfers objects from hand to hand, looks for dropped object
9 months Sits unsupported, begins to crawl
12 months Cruising (walking by holding furniture)
18 months Walks without assistance, speaks about 10-20 words
2 years Runs, climbs up and down stairs alone, makes 2-3 word sentences
3 years Dresses self except for buttons and laces, counts to 10, feeds themself well
4 years Hops on one foot, copies a cross
5 years Copies a triangle, skips

Attachment Theory and Harlow’s Monkeys

Attachment theory, developed by John Bowlby, suggests that children have an innate tendency to form relationships with people around them to increase their chance of survival. This attachment is different from bonding, which concerns the mother’s feelings for her infant. Children typically single out a primary caregiver, referred to as the principle attachment figure, from about 1-3 months. The quality of a person’s early attachments is associated with their adult behavior, with poor attachments leading to withdrawn individuals who struggle to form relationships and good attachments leading to socially competent adults who can form healthy relationships.

Bowlby’s attachment model has four stages: preattachment, attachment in the making, clear-cut attachment, and formation of reciprocal attachment. The time from 6 months to 36 months is known as the critical period, during which a child is most vulnerable to interruptions in its attachment. Attachments are divided into secure and insecure types, with insecure types further divided into avoidant and ambivalent types.

Harlow’s experiment with young rhesus monkeys demonstrated the importance of the need for closeness over food. The experiment involved giving the monkeys a choice between two different mothers, one made of soft terry cloth but provided no food and the other made of wire but provided food from an attached baby bottle. The baby monkeys spent significantly more time with their cloth mother than with their wire mother, showing the importance of attachment and closeness in early development.

Attachment Theory and Harlow’s Monkeys

Attachment theory, developed by John Bowlby, suggests that children have an innate tendency to form relationships with people around them to increase their chance of survival. This attachment is different from bonding, which concerns the mother’s feelings for her infant. Children typically single out a primary caregiver, referred to as the principle attachment figure, from about 1-3 months. The quality of a person’s early attachments is associated with their adult behavior, with poor attachments leading to withdrawn individuals who struggle to form relationships and good attachments leading to socially competent adults who can form healthy relationships.

Bowlby’s attachment model has four stages: preattachment, attachment in the making, clear-cut attachment, and formation of reciprocal attachment. The time from 6 months to 36 months is known as the critical period, during which a child is most vulnerable to interruptions in its attachment. Attachments are divided into secure and insecure types, with insecure types further divided into avoidant and ambivalent types.

Harlow’s experiment with young rhesus monkeys demonstrated the importance of the need for closeness over food. The experiment involved giving the monkeys a choice between two different mothers, one made of soft terry cloth but provided no food and the other made of wire but provided food from an attached baby bottle. The baby monkeys spent significantly more time with their cloth mother than with their wire mother, showing the importance of attachment and closeness in early development.

Developmental Stages

There are four main developmental models that are important to understand: Freud’s theory of psychosexual development, Erikson’s theory of psychosocial development, Piaget’s theory of cognitive development, and Kohlberg’s theory of moral development.

Freud’s theory of psychosexual development includes five stages: oral, anal, phallic, latency, and genital. These stages occur from birth to adulthood and are characterized by different areas of focus and pleasure.

Erikson’s theory of psychosocial development includes eight stages, each with a specific crisis to be resolved. These stages occur from infancy to old age and are focused on developing a sense of self and relationships with others.

Piaget’s theory of cognitive development includes four stages: sensorimotor, preoperational, concrete operational, and formal operational. These stages occur from birth to adulthood and are focused on the development of cognitive abilities such as perception, memory, and problem-solving.

Kohlberg’s theory of moral development includes three stages: preconventional, conventional, and postconventional. These stages occur from childhood to adulthood and are focused on the development of moral reasoning and decision-making.

Understanding these developmental models can help individuals better understand themselves and others, as well as provide insight into how to support healthy development at each stage.

During the formal operational stage, individuals possess the capacity to conceive of intangible concepts that are not perceptible through the senses. This includes the ability to formulate hypotheses and process abstract ideas.

Piaget’s Stages of Development and Key Concepts

Piaget developed four stages of development that describe how children think and acquire knowledge. The first stage is the Sensorimotor stage, which occurs from birth to 18-24 months. In this stage, infants learn through sensory observation and gain control of their motor functions through activity, exploration, and manipulation of the environment.

The second stage is the Preoperational stage, which occurs from 2 to 7 years. During this stage, children use symbols and language more extensively, but they are unable to think logically of deductively. They also use a type of magical thinking and animistic thinking.

The third stage is the Concrete Operational stage, which occurs from 7 to 11 years. In this stage, egocentric thought is replaced by operational thought, which involves dealing with a wide array of information outside the child. Children in this stage begin to use limited logical thought and can serialise, order, and group things into classes on the basis of common characteristics.

The fourth and final stage is the Formal Operations stage, which occurs from 11 through the end of adolescence. This stage is characterized by the ability to think abstractly, to reason deductively, to define concepts, and also by the emergence of skills for dealing with permutations and combinations.

Piaget also developed key concepts, including schema, assimilation, and accommodation. A schema is a category of knowledge and the process of obtaining that knowledge. Assimilation is the process of taking new information into an existing schema, while accommodation involves altering a schema in view of additional information.

Overall, Piaget’s stages of development and key concepts provide a framework for understanding how children learn and acquire knowledge.

Kleine-Levin Syndrome: A Mysterious Condition

Kleine-Levin syndrome is a peculiar disorder that typically affects adolescent boys. It is characterized by an excessive need for sleep and an insatiable appetite when awake. The condition is also associated with emotional and behavioral issues such as irritability and aggression.

The onset of symptoms is sudden and can last for several days to weeks before disappearing. This is followed by a period of normalcy, only to be followed by another episode. This pattern can continue for years, but the severity of symptoms tends to decrease over time. During the periods between episodes, those affected appear to be perfectly healthy with no signs of physical of behavioral dysfunction. The media has dubbed this condition as Sleeping Beauty syndrome.

Despite extensive research, the cause of Kleine-Levin syndrome remains unknown. However, the prognosis is generally positive, with most individuals making a full recovery.

Puberty

Puberty is a natural process that occurs in both boys and girls. The age range for the onset of puberty is between 8-14 years for females and 9-14 years for males, with the mean age of onset being 11 years for girls and 12 years for boys. The duration of puberty is typically 3-4 years. The onset of puberty is marked by the appearance of secondary sex characteristics, such as breast development in females and testicular enlargement in males. These characteristics evolve over time and are rated into 5 stages according to Tanner’s criteria. The sequence of events differs between boys and girls, with the onset of breast development (thelarche) generally preceding the onset of the first period (menarche) by around 2 years in girls. The pubertal growth spurt occurs during stages 3 to 4 in most boys and during stages 2 and 3 in girls. Precocious puberty, which occurs earlier than usual, is more common in girls than in boys. The age of onset of puberty in girls has been decreasing over time, with environmental factors such as nutrition potentially playing a role in this trend.

Development: Erikson and Marcia

Erikson’s theory of psychosocial development outlines eight stages of ego growth, each marked by a specific crisis that must be resolved for positive development. These stages range from trust vs. mistrust in infancy to integrity vs. despair in old age. Successful resolution of each crisis leads to positive growth and development.

Marcia expanded on Erikson’s theory, focusing on identity formation during adolescence. He described four separate identity statuses, which represent the four possible combinations of commitment and exploration. Identity confusion/diffusion occurs when adolescents neither explore nor commit to any identities. Foreclosure occurs when an individual commits to an identity without exploring options. A moratorium is a state in which adolescents are actively exploring options but have not yet made commitments. Individuals who have explored different options, discovered their purpose, and have made identity commitments are in a state of identity achievement.

Overall, both Erikson and Marcia’s theories emphasize the importance of positive resolution of developmental crises and the role of exploration and commitment in identity formation.

Mental Age and IQ

The concept of mental age (MA) was introduced by Alfred Binet in 1905. It involves administering a series of tests to a person of child, which are then ranked according to the age at which people are expected to complete them. The mental age can be used to calculate the intelligence quotient (IQ) using the formula: IQ = MA/CA x 100, where CA is the chronological age. An IQ of 100 indicates that the mental and chronological ages are equal. IQ tends to remain stable throughout life. The Stanford-Binet test was the first IQ test, while the WAIS-IV (Wechsler Adult Intelligence Scale) is the most commonly used IQ test today.

Lesch-Nyhan Syndrome: A Rare Genetic Disorder

Lesch-Nyhan syndrome is a rare genetic disorder that causes the overproduction and accumulation of uric acid in the body, leading to various health problems such as gouty arthritis, kidney stones, and subcutaneous tophi. The condition primarily affects males and is caused by mutations in the HPRT gene located on the X-chromosome.

People with Lesch-Nyhan syndrome typically experience motor disability, including severe dystonia, hypotonia, and choreoathetosis, which can make it difficult of impossible for them to walk of sit without assistance. They may also exhibit self-injurious behavior, such as biting and head-banging, which is the most common and distinctive behavioral problem associated with the condition. Intellectual disability is common, but severe cognitive impairment is rare.

The absence of the HPRT enzyme, which is responsible for recycling purine bases, leads to the accumulation of uric acid and affects the development of specific neural pathways in the brain, particularly the mesotelencephalic dopamine pathways. This disruption is likely responsible for the motor disability and behavioral peculiarities associated with the condition.

Treatment for self-injurious behavior typically involves the use of protective restraints applied to the limbs, trunk, of head to prevent self-hitting of self-biting. Dental extraction may be necessary in cases of lip of tongue biting. Behavior modification methods that involve extinction may also be used, but neuroleptics may be required during particularly stressful of difficult behavior periods. However, these medications should only be used transiently due to their sedative effects and potential side-effects.

Mahler’s Separation-Individuation theory of child development proposes that personality development occurs in distinct stages. The first stage, the Autistic phase, occurs during the first few weeks of life, where the child is mostly sleeping and cut off from the world. The second stage, the Symbiotic phase, lasts until around six months of age, where the child sees themselves and their mother as a single unit. The third stage, Separation-Individuation, has four subphases. The first subphase, Differentiation, occurs between six to ten months, where the child begins to see themselves as an individual and experiences separation anxiety. The second subphase, Practicing, occurs between ten to sixteen months, where the child explores connections with the external world and people other than the mother. The third subphase, Rapprochement, occurs between sixteen to twenty-four months, where the child struggles to balance their desire for independence and proximity to the mother, often resulting in tantrums and the use of transitional objects. The fourth subphase, Object constancy, occurs between twenty-four to thirty-six months, where the child accepts the idea of object constancy and is more comfortable with the mother being separate for periods of time.