Background
Schizophrenia is a severe, pervasive mental disorder that is characterized by positive symptoms such as hallucinations, delusions and disorganized speech in addition to negative symptoms including marked apathy, paucity of speech, and blunting or incongruity of emotional responses. The onset of schizophrenia before the age of 18 is commonly categorized as early-onset schizophrenia. This form of schizophrenia can have either an acute or gradual onset. The onset of schizophrenia before the age of 13 is considered as childhood-onset schizophrenia, which in most cases shows an insidious onset [
1]. The prevalence of childhood-onset schizophrenia is less than one in 10 000 children, but the prevalence of schizophrenia-related disorders among adolescents is about 1–2% [
2,
3].
Catatonia refers to a motor and mood dysregulation syndrome that includes motor signs such as stupor, mutism, negativism, grimacing, stereotypies and echopraxia/echolalia [
4‐
8]. Originally, catatonia was classified as a subtype of schizophrenia. During the last decades, it has been associated with a wide range of medical disorders, both somatic and psychiatric in character [
9]. In the DSM-5 classification, catatonia can be associated with another mental disorder, emerge in connection to another medical condition, or remain unspecific [
9]. Besides the clinical diagnosis of catatonia, a wide range of chronic, less severe, and sometimes very subtle symptoms of posture, movement, speech, and behavior are considered to be catatonic in nature [
10,
11]. The term “catatonia spectrum” is used to cover the whole range of these manifestations [
10].
Studies on adult patients with schizophrenia-related and mood disorders have reported incidences of catatonia that varied between10–38% [
4,
7,
8]. However, despite that catatonia also occurs among children and adolescents [
12], it has been sparsely studied among this age group. In a study by Thakur et al. [
13], 17.7% of the children and adolescents who suffered from affective and non-affective psychotic disorders showed at least two signs of catatonia. Green et al. [
14] reported that 31.6% of 38 hospitalized children with schizophrenia manifested catatonic features.
Pervasive developmental disorders (PDDs), affect 0.6–1% of the general population [
15], and share a core triad of abnormalities: 1. qualitative impairments in reciprocal social interactions, 2. qualitative impairments in verbal and non-verbal communication, and 3. restricted social imagination with repetitive and stereotyped patterns of interests and behaviour [
16]. Catatonic features have also been related to PDDs [
17]. Wing and Shah [
11] studied catatonia-like features in 200 children and adults with autism spectrum disorders (a broad equivalent of PDDs). They found that most of the participants had displayed some catatonic features during their lifetime. The items which occurred in more than three-quarters of the participants were: lack of facial expression, delayed echolalia, odd intonation, poor eye contact, and lack of cooperation. A prospective population-based follow-up study of 120 individuals with autism conducted by Billstedt et al. [
18] reported that approximately 12% of the autistic persons met the criteria for catatonia during their adolescence.
Recently, Shorter and Wachtel [
19] described historical patient vignettes in which catatonia, autism and psychosis were all present at the same time. According to the authors, these three diagnoses may represent three different manifestations of the same underlying brain disorder. Unfortunately, this “iron triangle” has been largely overlooked because its clinical features are conventionally seen as separate disorders. Yet, recognition of a mixed form of catatonia, autism and psychosis has important implications for both diagnosis and treatment.
The principal aim of the present study was to evaluate catatonic features among a consecutive sample of adolescents who were suffering from schizophrenia. Since both neuroimaging and genetic studies have reported that there is an overlap of symptoms between schizophrenia and PDDs [
20,
21], our second aim was to compare the nature and number of catatonic features between schizophrenia patients with a comorbid PDD and those without one. Further, we wanted to compare the profile of catatonia-like features of our schizophrenia patients to that described earlier among persons with autistic spectrum disorders without schizophrenia [
11]. Our hypotheses were that adolescents suffering from schizophrenia manifest catatonic features, and that these features are more frequent among patients with a comorbid PDD. We also hypothesized that the profile of catatonia-like features of adolescents suffering from schizophrenia resembles that reported among autistic persons.
Discussion
Our first hypothesis states that adolescents suffering from schizophrenia show catatonic features. This hypothesis was verified since the entire study group had presented many lifetime catatonic features. This finding is in line with the previous studies by Thakur et al. [
13] and Green et al. [
14].
Our second hypothesis states that catatonic features are more prevalent among adolescent schizophrenia patients with a comorbid PDD than those without one. We found that this was true in childhood but was no longer the case in adolescence. Wing and Shah [
11] chose their 28 specific items on the bases of clinical similarities between catatonia-like behavior and the unusual patterns of movement, speech, and behavior found in persons with autism spectrum disorders. These features are typically present already in early childhood and they have a tendency to become less marked with increasing age, especially in more able persons. In the present study, the number of catatonic features did not significantly change in transition from childhood to adolescence among the patients with a comorbid PDD. Among those without this comorbidity, the number of catatonic features increased significantly in transition from childhood to adolescence. In the future, it would be interesting to study whether this reflects the onset and impact of the schizophrenia process, although other factors, e.g. antipsychotic medication, may also contribute to this result.
More detailed analysis revealed that during their childhood, schizophrenia patients with a comorbid PDD differed from those without one in five specific items: “lacks facial expression”, “delayed echolalia”, “odd intonation”, “destructive behavior” and “strips in public”. This finding is, at least partially, a circular argument. “Lacks facial expression” and “stripping in public” can be regarded as qualitative impairments in reciprocal social interactions and “delayed echolalia” and “odd intonation” as qualitative impairments of verbal and non-verbal communication. Patients with PDDs also exhibit repetitive and stereotyped patterns of behaviour, and when those are prevented the person may get very anxious and sometimes even destructive. Thus, there is an overlap between catatonic features by Wing and Shah [
11] and the core symptoms of PDDs.
Over three-quarters of our patients shared four catatonic features during their lifetime: “lacks facial expression”, “odd intonation”, “poor eye contact” and “lack of cooperation”. On the other hand, none of our patients exhibited any features from the “visual fascination” subgroup. Wing and Shah [
11] reported that over three-quarters of their patients with autistic spectrum disorders shared these same four catatonic features plus the feature called “delayed echolalia”. The authors also reported that the frequencies of features in the “visual fascination” subgroup were very low. Given the fact that the authors had a sample of 200 autistic persons of whom a substantial proportion (35%) suffered also from mental retardation, it is interesting to note this overlap between their and our results.
In a study by Wing and Shah [
29] about one in seven patients with autism spectrum disorders fulfilled the clinical diagnosis of catatonia. Kakooza-Mwezine et al. [
30] have noted that the risk of developing clinical catatonia is about the same in persons with autism as in those suffering from affective and psychotic disorders. Further studies with follow-ups from childhood to adulthood are needed to find out whether differences in the occurrence of clinical catatonia as conceptualized in the DSM-5 among schizophrenia patients with and without a comorbid PDD will emerge. The same naturally applies to catatonia-like features and their waxing or waning or possible exacerbation into clinical catatonia.
The strengths of our study include recruiting patients on a consecutive basis from inpatient units in a geographically defined area. In addition, structured instruments with good psychometric properties were used in combination with primary documents from early childhood, which are readily available in Finland. Nevertheless, the study has its obvious limitations. The small sample size reduces the generalizability of our findings and the results must be regarded as preliminary. Moreover, the current study may have been underpowered to detect smaller statistical group differences that could have been detected in a larger sample. Further, our adaptation of the DISCO interview by splitting it into childhood and adolescence sections has not been validated. However, our use of the DISCO was in accordance with the original structure and design of this diagnostic instrument.
Competing interests
The authors declare no conflict of interest.
Authors’ contributions
PW planned the study, collected, organized and analyzed the data and served as the first author. NL participated in the planning, analysis and writing processes. KK participated in collecting the data. JL performed statistical analyzes. PT supervised the study project and participated in the writing process. All authors read and approved the final manuscript.