Prader-Willi Syndrome and Positive Behavior Support
An Alternative Method of Treatment

Stanley L. Swartz, Ph.D.
California State University


Prader-Willi Syndrome is a syndrome that is characterized by mental retardation, short stature, obesity, hypogonadism, and hyperphagia (compulsive eating). The syndrome is relatively rare, affecting approximately 1 in 15,000 people. Various learning and behavioral difficulties make Prader-Willi difficult to treat. Tradition methods of behavior modification have been used with some success in school and home environments. Positive Behavior Support (PBS) is found to hold great promise as an alternative method of treatment. PBS shifts the focus from the typical manipulation of consequences used in behavior modification to the analysis of environmental and behavior deficits. These data are then used to determine the function of inappropriate behaviors and design a positive approach to teaching appropriate behaviors.

Research on Characteristics of Prader-Willi

There has been considerable research on Prader-Willi Syndrome since it was first described in 1956 by Prader et al. This research has focused on genetics, major physical characteristics, hypothalamic dysfunction, medical abnormalities, psychological and behavioral characteristics, cognition, and learning difficulties (Waters, 1999). Research on effective treatment methods has been less extensive though various behavioral techniques have been found to be the most effective.

Genetic background

PWS can be caused by more than one genetic abnormality, but all are related to missing genetic coding from the paternal chromosome 15.

Major Physical Characteristics
Low muscle tone is evident from birth, including poor sucking ability which makes feeding difficult and has implications for later speech problems. Muscle tone can be helped with appropriate exercise (Eiholzer et al., 1998)
Evident earlier in males however both males and females experience delayed puberty.
The tendency to obesity can be life threatening and is caused by excessive eating and low physical activity.
Typical facial characteristics
Facial features might include a narrow forehead, ‘almond shaped’ eyes with upward slanting lower eyelids, and a down turned mouth. Hair and skin coloring is often lighter than family members.

Hypothalamic Dysfunction
Hyperphagia (eating more food than required)
Excessive appetite is the most well known feature of PWS. The mechanism that informs most people that they have had enough to eat is faulty in PWS and results in numerous behavior problems, i.e., stealing food from others, eating pet food.
Short stature
Average height without hormone treatment is 4’10” for females and 5’2” for males. Hands and feet are both typically smaller.
Somnolence, tiredness
Because sleeping patterns are regulated by the hypothalamus these are usually affected in PWS. Children usually require naps and adults are prone to daytime sleepiness.
Emotional instability
Both delayed and arrested emotional development are typical. These include various acting out behaviors as well as temper tantrums and stubbornness.

Other Medical Abnormalities
These medical abnormalities vary from individual to individual but are sometimes associated with PWS.
Adverse reaction to drugs
Some adverse effects have been found from drugs that affect the central nervous system (e.g., tranquilizers).
Prolonged drowsiness after anesthesia
Use of general anesthesia has been known to cause prolonged drowsiness.
Irregular body thermostat
The hypothalamus also controls body temperature and erratic behavior might be noted in extreme hot or cold weather.
High pain threshold
Both hyper and hyposensitivity to pain might be present.
Easy bruising
Careful monitoring of a child’s activity is necessary both because of pain threshold and because of easy bruising.
Lack of vomiting
Low muscle tone can result in the inability to vomit.
Visual impairments
Eye squinting and myopia (shortsightedness) are common. Nystagmus (involuntary jerking of the eyeball) has also been reported.
Curvature of the spine
Scoliosis is the most common curvature in PWS.
Skin problems
Both eczema and cellulitis are high risks for PWS.
Immature sexual development and delayed puberty
Secondary sex characteristics are slow to develop in both sexes and menstruation is later for girls. PWS are not sterile but have a high risk for various genetic abnormalities.
Dental and oral problems
Oral problems include thick saliva. Dental problems can include poor tooth enamel, high palate, and a small jaw.
Diabetes is associated with significant obesity.
Speech and language problems
Common in both children and adults.

Psychological and behavioral characteristics
Various researchers have tried to identify a behavioral phenotype for PWS that might have a genetic basis (Dykens & Kasari, 1997; Curfs et al., 1995; van Lieshout et al., 1998; Dykens & Cassidy, 1995).
Temper outbursts
Temper tantrums are frequent and can be extremely violent and unpredictable.
Stubbornness is linked to the desire to keep a routine.
Resistance to change
Need for routine is similar to that found in children with autism.
Obsessive and/or compulsive behavior
This behavior is found in as many as 80% of PWS. Obsessive behaviors intrude on appropriate participation in activities.
Hoarding and possessiveness
Hoarding and being unwilling to share is common in PWS and is linked to obsessive/compulsive behaviors.
This is usually manifested as persistent talking or questioning on one topic.
Skin picking
Unique to PWS, this behavior starts with children picking an existing spot or wound and spreads to other parts of the body.
Immature social skills
Difficulties with turn taking or being part of a group are common. Most are eccentric and have problems understanding other’s points of view.

Most PWS individuals are within the mild mental retardation range and many have severe learning difficulties. Though the range of intellectual ability varies, most do not perform at their tested level of ability.
Strengths and weaknesses
A chart of strengths and weaknesses using teacher data describe these various behaviors.


Relationship between intellectual ability and behavior
High I.Q. does not seem to protect PWS from behavioral manifestations associated with the syndrome (Dykens & Cassady, 1995).
Relationship between intellectual ability and obesity
This relationship has not been established. It is theorized that those with higher intelligence are more resourceful in seeking out food sources (Dykens et al., 1992).
Relationship between intellectual ability and age
Ability has not been found to decrease with age but is rather a phenomenon of an increasing ability gap between PWS and peers (Taylor, 1988).

Speech and language disorders
Speech disorders are common and occur in as many as 70% of PWS individuals. These can be the result of oral motor abilities. Problems in pitch have also been noted (Akefeldt et al. 1997). Expressive language has been found to be more impaired than receptive language (Kleppe et al., 1990).

Specific learning difficulties
Difficulty with auditory processing
This problem might result in having difficulty understanding verbal instructions or receiving too many instructions at once.
Repeated questioning on the same topic is a common behavior.
Difficulties with abstract concepts
Time concepts and temporal meanings are frequently confused.
Difficulty with problem solving strategies
Some stubbornness can be attributed to difficulty with sequential processing.
Rigid thinking
What is learned will be difficult to unlearn. This form of concrete thinking makes it difficult to follow a line of logic or learn from experience.
Poor short-term memory
Though short term memory is a problem (what is learned one day might be forgotten by the next) long term memory for persons, places and events might be very good.
Difficulty with applying methods
Even directions learned by rote can be difficult to understand or apply. A rule that applies in one situation might not be used in another similar situation.

Treatment and Education
Treatment for individuals with PWS needs to be carefully designed with special attention to behaviors that are associated with the syndrome. Few medical treatments are known to be effective therefore treatment and educational methods are primarily those that focus on behavior management and teaching of appropriate behaviors. Particular emphasis will need to be given to dietary needs and supervision, behavioral problems with focus on temper tantrums and obsessive behaviors, social skills, and inclusion in classes and activities with normal children. If successful intervention is to be accomplished, consideration must be given to the development of social skills and other appropriate behaviors that will contribute to successful integration in school, community, and home environments (Swartz, 1998). Work with individuals with PWS must include techniques that meet a high standard of social acceptability. To accomplish this, a system of behavior change that is as effective as typical behavior modifications programs yet is appropriate in home and community settings, has been identified.

Positive Behavior Support
One of the major obstacles to the treatment of individuals with Prader-Willi Syndrome, in school, community, and home settings, is behavior that is inappropriate and disruptive. Behaviors such as tantrums, stubbornness, various compulsive behaviors (in particular compulsive eating), are challenging beyond what many teachers and parents are prepared to handle. Families and those who work with individuals with Prader-Willi Syndrome are looking for treatment methods beyond the traditional manipulation of consequences offered by most behavior management programs.

If appropriate programs are to be designed, ones that allow a normal family life, it will be necessary not only to identify treatment methods that work, but ones that will be acceptable in the context of inclusive environments. The three concepts of social validity identified by Wolf (1978) are important considerations in reaching this goal. These are, feasibility - are we able to use the strategy; desirability – are we willing to use the strategy; and effectiveness – does the strategy make a difference for the individual in increasing inclusion opportunities? In other words, treatment strategies are needed that both parents and teachers are able and willing to use and that make a real difference for the lifestyle of the individual and their opportunities to participate in school, community and home.

An increasing body of research in the use of positive behavior support (PBS) has demonstrated that these strategies are highly effective for use with the behaviors presented by children with severe disabilities (Carr, Horner & Turnbull, 1999). In addition, PBS meets the various social validity criteria in most cases and facilitates inclusion of children with disabilities. Unlike traditional behavior management, which views the individual as the sole problem and seeks to “fix” him or her by quickly eliminating the challenging behavior, PBS views such things as settings and lack of skill as parts of the “problem” and works to change those. As such, PBS is characterized as a long-term approach to reducing the inappropriate behavior by teaching a more appropriate behavior, and providing the contextual supports necessary for successful outcomes (ERIC, 1999).

Effective behavior change must not only reduce inappropriate behaviors it must also teach suitable alternatives. These changes should not only help the individual in the immediate environment, or the short term, they must also be important for their life after school, or the long term. The key concept of PBS was then determined to be to change a problem behavior, it is first necessary to remediate deficient contexts. Deficient contexts were found to come in two varieties, those related to behavior repertoires and those related to environmental conditions. Behavior repertoires means that the individual does not have the necessary behaviors to be successful. Communication skills, social skills, self-management are all found to be inadequate for the demands of their day-to-day existence, whether in school, home, or community. Environmental conditions means that the stimuli in any particular environment are not conducive to appropriate behavior for this individual and contribute to the emergence of problem behaviors.

In applying PBS, the research review completed by Carr and his colleagues found two categories of intervention: stimulus-based and reinforcement-based (Carr, et al., 1999). When environments are deficient it is when there are too few stimuli to support positive behavior and that changes in this environment are necessary as part of the effort to help children with disabilities exhibit more appropriate behavior. On the other hand, from a reinforcement perspective, the existence of positive behaviors competes with or makes negative behaviors unnecessary because the positive behaviors provide an alternative for accessing the available reinforcement. In sum, PBS tries to change the environment so that the conditions for appropriate behavior and its reinforcement are available and to teach appropriate behaviors as a substitute for accessing reinforcement in the environment.

Positive behavior support appears to be best suited for long-term change and is proactive to the extent that it attempts to teach behaviors and impact the environment that surrounds these behaviors. This is contrasted to aversive or punitive approaches that seem best suited to crisis management. From the perspective of the family, and in keeping with the principles of social validity, PBS would seem to be the appropriate choice because of its good fit with a family environment. Parents are able to work with their children using techniques that are effective and at the same time part of a normal pattern of interaction. From the perspective of the school, PBS is a good match because of its suitability for use in inclusive settings and because it is primarily a teaching method. Positive behavior support is a procedure more likely to encourage the inclusion of children with disabilities in general classrooms.

Using Positive Behavior Support with Prader-Willi Syndrome

Functional Analysis of Behavior
The use of PBS is initiated with a functional analysis of behaviors. This process answers the question of what function(s) does the problem behavior serve for the individual? What might the person be communicating? The hypothesis that should be developed for each problem behavior is: 1) when does the behavior happen? (what are the specific antecedent and setting events that are associated with this behavior?), 2) describe the specific problem behavior, and 3) what are the possible function(s) of this behavior? Common functions and communicative intent of problem behaviors include: 1) to gain access to social interaction, 2) to gain access to activities, objects, food, 3) to terminate or avoid unwanted situations, and 4) to gain access to stimulating events (Bambara & Knoster, 1998).

Antecedent and Setting Event Modifications
A first step of intervention that can have powerful results is to consider the environment and any events that might be antecedents to problem behaviors. Modifications of this kind have the advantage of avoiding undesirable behaviors by making changes before they occur. These might include: 1) removing a problem event such as avoiding a situation known to agitate the individual, 2) modifying a problem event such as shortening the expectation for on-task behavior, mixing hard and easy tasks using new tasks with mastered tasks, 3) adding events that promote desired behavior such as providing for choice and preferences, and 4) neutralizing the impact of negative events by allowing frequent breaks during difficult tasks.

Teaching Alternative Skills
Rather than focusing on undesirable behaviors, PBS focuses on the desired behavior. It is assumed that the individual does not have the appropriate behavior or does not have it in sufficient strength to use it when it is needed.

These might include: 1) replacing skills where the behavior taught is a one-to-one substitute for the function of the undesirable behavior, 2) teaching general skills that can help the individual change a problem situation and avoid the need for the problem behavior, and 3) teaching coping and tolerance skills needed to help the individual deal with problems that they encounter.

Management of Consequences
The management of consequences of behaviors is a method used to teach an individual to use alternative behaviors. This teaching is part of the PBS approach as contrasted to the primary focus of typical behavior management systems that only apply consequences. These might include: 1) increasing the use of alternative behaviors by prompting the use of the appropriate behavior and subsequent reinforcement, 2) reducing the outcomes of inappropriate behavior by redirecting the individual to an appropriate behavior or providing corrective feedback, and 3) implementing a crisis management procedure that redirects the individual to more appropriate responses and behaviors.

Behaviors that Affect Lifestyle
When we think of lifestyle we think of the routines of normal life and the behaviors necessary to successfully participate in inclusive settings. The overriding factor in program development is to consider how the quality of life is improved for the individual. These might include: 1) teaching behaviors that focus on relationships, choice and control, preferred activities, and inclusion, and 2) focus on permanent adaptations and skills that can be used in various settings (Bambura & Knoster, 1998).

Redirective Therapy with Prader-Willi Syndrome
Redirective Therapy was developed as part of a training program in a university clinic for parents and families of children with severe disabilities (Swartz, 1994). Parents had reported that though some techniques currently available appeared to be effective, they were too harsh and too unusual as a pattern of parent-child interaction. They felt that the treatment became an aversive to both parent and child because of its intensity and that its suitability for the community or an inclusive school setting was also an issue. The criteria used in the development of Redirective Therapy (RT) was that it must allow for a positive interaction between parents and their children and that it must be suitable for use in all settings. Using research in nonpunitive techniques (Donnellan, et al., 1998), the strategy focused on a simple pattern of redirection with teaching an appropriate behavior as the end goal. Similar in this regard to the strategy identified as differential reinforcement of alternative behavior (DRA), Redirective Therapy diverged by electing to use only social rewards. It was felt that since one of the primary goals for most children in the program was increased socialization, the use of social rewards would be the first important step in teaching social skills. Redirective Therapy is an application of Positive Behavior Support that can be applied in inclusive settings (school, community, and home) and used by individuals without specific professional training, (i.e., parents and caretakers). It also begins with a functional analysis of behaviors. Both the environment and the behavior repertoire of the individual are considered. Environmental impacts on problem behavior are modified or removed as a first step. Specific behaviors that the individual needs are the focus in the next steps. Rather than focusing on undesirable behaviors, RT focuses on teaching children appropriate alternative behaviors that have the same function.

Parents, therapists and teachers using RT are taught to interrupt the undesired behavior and redirect the child to an appropriate behavior. They are instructed to do this interruption in the least intrusive way possible (for example, a word or a gesture would be a preferable interruption to a physical cue). Social reinforcement (praise or touch, or both) would immediate follow the interruption and redirection. In this way, the concern about limited availability of reinforcement in the use of differential reinforcement of other behaviors (DRO) is resolved. This pattern is repeated until the child stays on the new task and exhibits an appropriate behavior. Parents report that their positive feeling about this strategy is that they can use it at home and on any trips into the community. In another words, it meets both the social validity criteria of feasible (I can use it) and desirable (I will use it).

The cycle of Redirective Therapy illustrated is a pattern of interaction that can be used by parents, therapists or teachers in any setting. It does not rely on external or tangible reinforcement and should result in a higher level of internalization. The particular advantage for using RT with PWS is the coordination of teaching methods between home and school and the normal pattern of interaction that it represents. Punishment and negative reinforcement have no place in efforts to treat individuals with Prader-Willi Syndrome.

Educational Curriculum

In addition to particular emphasis on behaviors necessary to participate in school settings such as establishing classroom routines and expectations, and management of various inappropriate behaviors, consideration needs to be given to the development of academic skills and achievement. With carefully planned instruction most individuals with PWS can succeed in both literacy and numeracy. Learning difficulties referenced earlier will be an important part of developing individualized educational programs.

Numeracy skills are more difficulty because of deficits in abstract concepts. Using the same concept or procedures for more than one problem is an additional difficulty. Generally success will depend on the resourcefulness of the teacher in making numeracy concepts concrete. Individuals can be expected to also use spatial concepts more effectively than those that are abstract. Teaching methods that emphasis small steps and using mathematical concepts in real life applications are more likely to result in progress.

Literacy is generally reported as a strength in individuals with PWS. Writing might be affected by poor muscle development and motor control, but reading can be considered an opportunity to excel. Nevertheless, students often learn reading skills by learning to write their own messages (Swartz, Klein, & Shook, 2001). The reciprocity of reading and writing (what one reads, one can also write) should be emphasized. Individuals with PWS have been found to learn words by sight rather than by phonic analysis. Comprehension is often a mismatch for what the individual is able to decode and read out.

Direct instruction in reading needs to include helping individuals develop the necessary reading behaviors to decode and understand text. These include: 1) monitoring your own behavior as you read, 2) comparing sources of information in the text, phonics and comprehension, 3) fluency, where the reader is encouraged to read at the usual rate of speaking, and 4) correction, the reader recognizes errors and corrects them as they read (Swartz, Shook, & Klein, 2003).

The following chart can be used as prompts for teachers and parents to support reading development.

In addition, once the individual has read text, it is important to make sure that they are reading for meaning and not just calling words from memory. The following chart includes various questions that can be used to probe for comprehension.


Individuals with Prader-Willi Syndrome can be successful in both social and academic settings with appropriately designed programs of treatment that consider the major characteristics of the syndrome. Using strengths and teaching appropriate behaviors should be the primary focus. Training of parents and teachers in Positive Behavior Support is a necessary part of coordinating efforts between home and school and increasing the opportunities for individuals with Prader-Willi Syndrome to participate in inclusive settings.

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Carter, C.H. (1975). Handbook of mental retardation syndromes (3rd edition). Springfield, IL: Charles C. Thomas.

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Kleppe, S.A., et al. (1990). The speech and language characteristics of children with Prader-Willi syndrome. Journal of Speech and Hearing Disorders 55, 300-9.

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Swartz, S.L., Shook, R.E., & Klein, A.F. (2003). Guided reading and literacy centers. Carlsbad, CA: Dominie Press.

Swartz, S.L., Klein, A.F., & Shook, R.E. (2001). Interactive writing and interactive editing. Carlsbad, CA: Dominie Press.

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Prader-Willi web sites
In Spanish Prader Willi association web site (English/Spanish) Spanish Prader Willi site Spanish version in California International Prader Willi Society Organization (various languages) Prader Willi in Chile

Related web site maintained by Dr. Swartz

Other Prader-Willi web sites Prader Willi in New York Prader Willi in Ontario, Canada outline of Prader Willi basic Prader Willi info Research organization Prader Willi FAQ page Prader Willi site Prader Willi in the UK Prader Willi paper Prader Willi genes and disease site Prader Willi general practitioners site Prader Willi in New Jersey Arizona chapter of Prader Willi Prader Willi in Australia Prader Willi in Argentina Prader Willi in New Zealand Prader Willi in South Carolina Prader Willi in Germany Prader Willi in Ohio Prader Willi in Florida Prader Willi and Angelman syndrome Contact a Family Organization Genetic Drift

Stanley L. Swartz, Ph.D.
Professor of Education
California State University
Visiting Professor, Facultad de Cientas Humanas,
Universidad Autonoma de Baja California
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