The Big-Seven Early Markers for Childhood-Onset Psychosis Spectrum Disorders
Tigerson M. Young, Ph.D.
Guilford Early Psychosis Intervention Program, Surrey, British Columbia, Canada
Assessing psychotic symptoms in children, particularly in those that are under the age of 12, can pose a special challenge to many clinicians. Recent studies have pointed to the direction of understanding the psychosis spectrum disorders from the neurodevelopmental model. The purpose of this review is to discuss the seven markers (i.e. affected first-degree relatives, impaired attention, impaired cognitive functioning, neuromotor difficuty, social impairment, attenuated positive symptoms, and impaired working memory, using the acronym RAINS-PM) that are readily observable by most out-patient clinicians. Using these identifiers may be helpful for making differential diagnoses of an emerging psychosis from anxiety and mood related disorders.
Early-onset psychosis; Child mental health; Schizophrenia; Early identifiers
Assessing children with psychotic symptoms, especially those that are younger than 12 years old, can present a special challenge to mental health clinicians. Currently, there are no consistent findings and protocols available for assessing children that display psychotic symptoms (Asarnow, Tompson, & McGrath, 2004; Hlastala & McClellan, 2005; Keshavan et al., 2002; Stayer et al., 2004). Their presentations could be a result of a variety of possibilities, ranging from an emerging psychosis to anxiety or mood disorders. Thus, it is important to locate diagnostic identifiers so that clinicians may render a more accurate diagnosis. Different cognitive functions, such as attention, intellectual functioning level, neuro-motor activity, and working memory, are said to be promising markers for identifying an emerging psychosis in children (Brewer et al., 2006; Cervellione et al., 2007; Wood et al., 2003). This paper is to review the current literature on this topic.
Psychosis: An Overview
Psychotic disorders include an array of disorders, such as schizophrenia, schizophreniform disorder, schizoaffective disorder, delusional disorder, brief psychotic disorder, bipolar disorder, and major depression with psychotic features, to name a few (American Psychiatric Association, 2000; Ehmann & Hanson, 2004). Given the heterogeneity and the complexity of these disorders, it may be more useful to conceptualize them using a spectrum perspective than viewing them as a single disorder. Therefore, it may be more useful to call them psychosis spectrum disorders (PSD). These disorders share the common presentation of the presence of thought and perceptual disturbance and impairment (Hlastala & McClellan, 2005). While the age of onset for the more severe forms of psychotic disorders, such as schizophrenia, was once believed to be in the late adolescence and young adulthood, recent research showed that the disorders could be a neurodevelopment disorder (Rapoport, Addington, Frangou, & MRC, 2005; Schenkel & Silverstein, 2004). In other words, the age of onset could be much younger for those who have certain neurological predisposition (Masi, Mucci, & Pari, 2006). For example, a study conducted by the University of California, Los Angeles on the onset of psychotic symptoms indicated that the mean age of onset in its study was 6.9 years (Russell, Bott, & Sammons, 1989). Some even suggest that the disorders may be related to the neurodevelopment process in the fetal stage (Rapoport et al., 2005).
The main concern for clinicians is, of course, how to tease out whether or not these psychotic symptoms are a prodromal state of an emerging psychosis (Amminger & Klier, 2004). From an epidemiological perspective, the overall prevalence rate worldwide of the more severe forms of PSD, such as schizophrenia, is about 1% of the total population (Cornblatt, Green, & Walker, 1999). The overall prevalence rates worldwide for other PSD, such as bipolar disorders and schizophreniform disorder, are similar, ranging between 0.2% and 1.6% (O’Leary & Norcross, 1998). The prevalence rates of these disorders among children, particularly for those who are younger than 12 years, are sporadic. Depending on which study, the prevalence rate of childhood-onset schizophrenia is said to be about 0.01% (Eggers, Bunk, Volberg, Ropcke, 1999). The prevalence rate of bipolar disorder in children is said to be less than 0.1% (SFU, 2007). Therefore, chances are rare and that only a fraction of the children with psychotic symptoms would qualify for having a diagnosis of an emerging psychosis (Remschmidt et al., 2007). On the other hand, anxiety and depression have a much higher prevalence rate, ranging from 5% to about 17% (O’Leary & Norcross, 1998), and the lifetime prevalence for anxiety disorder is around 29% with a median age of onset of 11 years of age and the lifetime prevalence for mood disorders is 25% with a median age of onset of 30 years of age (Kessler et al., 2005). Therefore, identifying the diagnostic markers for an emerging psychosis, especially in children, will be very helpful and important for clinicians in making an educated differential diagnosis.
Literature review was conducted using electronic databases, such as Academic Search Premiere, Medline, and PsychInfo. Certain keywords were used, such as childhood-onset schizophrenia, early psychosis, early identifiers, and biomarkers. Only materials in English and human participants were included in the search. Some markers, such as chromosomal abnormality and brain structural differences, are not readily identifiable by clinicians in an out-patient setting (O’Neil et al., 2004; Rapoport, Addington, Frangou, & MRC, 2005). They are, therefore, not included in this review. Given these inclusive and exclusive criteria, seven viable diagnostic identifiers were located as a result of the review.
What are some of the diagnostic markers for an emerging psychosis, as opposed to anxiety and depression, which a clinician may use to assess a young child with psychotic symptoms? Recent research has suggested an array of markers, such as attention, cognitive ability, and working memory, to name a few (Brewer et al., 2006; Cervellione et al., 2007; Wood et al., 2003). While some studies have suggested that the childhood-onset schizophrenia has a similar presentation and assessment procedure as the adult-onset schizophrenia (Asarnow, Tompson, & McGrath, 2004; Masi, Mucci, & Pari, 2006), false positives are high as well (Stayer et al., 2004). Thus, knowing these diagnostic markers will help decrease the possibility of misdiagnosis and false positives. Many of these diagnostic markers are general and are present in different psychological disorders. Therefore, it is important to look for the aggregate of these diagnostic markers, instead of just focusing on an individual marker, in order to have a more accurate diagnostic picture. The following is a more in-depth discussion of the seven diagnostic markers that are readily usable by out-patient clinicians and suggestions on what types of tools are available to assess each of the seven areas. And, they are conveniently called RAINS PM:
Affected First-Degree Relatives (R)
Probably, one of the most prominent markers is the presence of an affected first-degree relative (Keshavan et al., 2002). Medical genetic studies have shown that there is a high heritability of psychotic disorders (Sorter, 1998). Lyons and his colleagues (1995), for example, reported that the perceptual aberration among siblings is familial, with the sibling intraclass correlations and heritabilities (h2), using the psychosis proneness scales, in the upper quadrant (h2 = 0.62, p < .05) in their studies. Avila et al. (2006) also found that the neurocognitive performance between relatives of clients with schizophrenia and clients with schizophrenia was very similar, suggesting that the impairment in cognition could be a heritable domain of dysfunction and might be a phenotypic trait of psychotic disorders. Therefore, having a thorough family history will help identify the genetic vulnerability of the children with psychotic symptoms when assessing the possibility of an emerging psychosis. A number of tools are available in the market today to conduct thorough family history assessment. One of them is the Structured Developmental History questionnaire (SDH), which is part of the Behaviour Assessment System for Children (BASC-2; Reynolds & Kamphaus, 2004).
Impaired Attention (A)
Another important marker is the ability to focus and to pay attention. Keefe and his colleagues (2006) compared 37 participants that matched the criteria of having a prodromal state of psychosis with 59 participants that had their first episode of psychosis and 47 healthy participants. Their results indicated that poor performance on the attention task, using the Continuous Performance Test (CPT) – Identical Pairs version, was one of the significant markers in predicting eventual development of psychosis among the prodromal participants. The authors also pointed out that “a combination of poor CPT performance and better WAIS-R digit – symbol performance significantly predicted psychosis development” (Keefe et al., 2006, p. 34). Another study also indicated that 31% of the adults with psychosis in their study had a history of Attention Deficity/ Hyperactivity Disorder (ADHD) in their childhood, suggesting attention could be a useful marker for identifying psychosis (Keshavan et al., 2002). Therefore, using an attention assessment tool, such as the Conners’ Continuous Performance Test (CPT-II), may help identify problems with attention (Conners, 2004), which may be an indication of having an emerging psychosis. Of course, the majority of youth who have attention problems do not develop psychosis. Again, it is important to recognize that attention is only one piece of the diagnostic puzzle.
Impaired Cognitive Functioning (I)
Cervellione and her colleagues (2007) found that the neurocognitive deficits were “a stable, trait-like feature of the disorder” in their study (p. 875). Some suggest the pre-morbid deficits could range anywhere from 1.0 to 2.0 standard deviations (Hoff et al., 1999). In other reports, findings suggest that there is not only a lower starting point, but that the neurocognitive functioning levels of clients with psychosis, children and adults alike, declines during the developmental process of their illness. Eberhard, Riley, and Levander (2003), for example, reported in their study of 35 Swedish clients, who had schizophrenia, that they had lost at least 1.0 standard deviation in most of the cognitive tests in their study when their intellectual functioning level was compared before and after their development of schizophrenia. Therefore, including a standardized cognitive test batteries, such as the Wechsler scales or the Stanford-Binet scales, are warranted when assessing the possibility of having an emerging psychosis (Brewer et al., 2006).
Neuromotor Difficulty (N)
Schenkel and Silverstein (2004) reviewed neuromotor function as one of the identifiers for emerging psychosis. The authors pointed out that a host of studies has noticed a history of childhood motor development delays and difficulties are correlated with the development of schizophrenia in adulthood (e.g. Schiffman et al., 2004; Walker et al., 2004). This is also related to the current functioning level of perceptual – motor speed. Albus et al. (2006), for example, studied 71 patients that had experienced their first episode of psychosis throughout a 5-year-study. Their results indicated that these patients had the “most pronounced deficits” in the areas of “visuomotor processing and attention” (Albus et al., 2006, p. 447). Therefore, collecting information on the early development of neuromotor functioning level and using a standardized test, such as Block Design from the Wechsler scales or the puzzle from the Stanford-Binet scales may be helpful in locating this identifier.
Social Impairment (S)
According to a multi-site longitudinal study across North America, social impairment was one of the key predictors of psychosis among the 291 participants in the study. The mean age of the participants in the study was 18 years old. The findings suggested that “the poorer the social functioning and the more severe the subsyndromal symptoms at ascertainment, particularly in the domains of unusual thought content and suspiciousness, the closer the subject is to the onset of psychosis” (Cannon et al., 2008, p. 33). Social Skills Rating Scale (SSRS), for example, is a good tool for assessing this area (Gresham & Elliott, 1990).
Attenuated Positive Symptoms (P)
Another helpful identifier is to examine the contents of the positive symptoms. Usually, if it is an emerging psychosis, it may include positive symptoms that are more bizarre and magical, such as illusions, ideas of reference, and magical thinking, than the psychotic features that are a result of anxiety or depression (Amminger & Klier, 2004). Hlastala and McClellan (2005), for example, studied 75 youth, ages 7 to 18 years of age, with psychosis in a 2-year study. Their results indicated that atypical psychotic symptoms were very different than the typical psychotic symptoms in their study. They found that the atypical symptoms were usually “context-specific, overly elaborative, and/or responsive to secondary gain” (Hlastala & McClellan, 2005, p. 504). Therefore, the authors suggested that these atypical psychotic symptoms were “more likely to be related to dissociative and/or post-traumatic phenomena, rather than a current or developing psychotic illness” (p. 505). Clinicians may find scales, such as the Chapman’s Magical Ideation (Ekblad & Chapman, 1983) and Perceptual Abberation (Chapman et al., 1978) Scales, helpful in differentiating typical and atypical psychotic symptoms.
Impaired Working Memory (M)
In addition to attention, studies have shown that the working memory (WM) for those who have emerging psychosis is severely debilitated. Yoo and colleagues (2005), for example, studied twelve 18 to 45 year-old patients who had been diagnosed as having schizophrenia and compared them to 12 demographically matched volunteers. Their results indicated that the patients had “an impaired facial WM” when compared to the volunteers (Yoo et al., 2005, p. 358). A meta-analytical study on 124 studies by Lee and Park (2005) concluded a very similar finding that “working memory deficits in schizophrenia are reliably found across very diverse methods and approaches,” suggesting that “common cognitive processes necessary to perform working memory tasks maybe abnormal in schizophrenia” (p. 602). Again, using a standardized tool, such as the Digit Span from the Wechsler scales or the Memory for Sentences from the Stanford-Binet scales may be helpful in identifying working memory concerns.
Other Areas of Concerns
Other markers, such as a declining academic performance, deficits in other executive functions (e.g. organizational skill), obstetric complications, substance use (e.g. cannabis), and social factors (e.g. unemployment and early separation from both parents), have been suggested by various studies to have a significant role in the development of psychosis as well (Keefe et al., 2006; Mallett, Leff, Bhugra, Pang, & Zhao, 2002; Rapoport, Addington, Frangou, & MRC, 2005; Solowij & Michi, 2007). Clinicians may want to pay attention to these areas as well.
The study of PSD, particularly childhood-onset emerging psychosis, is an exciting field. From the traditional perspective to the neurodevelopmental model, we can only expect more changes in our understanding of these disorders when research results are available in the near future with the help of neuroimaging and medico-genetic technologies (Ehmann, MacEwan, & Honer, 2004; Masi, Mucci, & Pari, 2006; Rapoport, Addington, Frangou, & MRC, 2005). Childhood-onset emerging psychosis may as well represent a unique subgroup of the PSD. In the mean time, using the acronym, RAINS PM, may be a viable option for out-patient clinicians to look for identifiers and markers that may suggest an emerging psychosis from children that display psychotic symptoms. While several of these markers are identified, what their loadings are on the onset of psychotic disorders in children is still subject to more study. Future study may want to focus on this that clinicians may know to what extent each of these markers has played in the development of these disorders in children.
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First Published July 2008