Psychopathological Differences Between Asperger Syndrome and Schizotypal Disorder in an Adult Sample
Condition: Asperger Syndrome; Autism Spectrum Disorder; Schizotypal Personality Disorder
MeSH terms: Syndrome; Autistic Disorder; Autism Spectrum Disorder; Child Development Disorders, Pervasive; Personality Disorders; Asperger Syndrome; Schizotypal Personality Disorder
Study type: Observational

Summary: 
      The purpose of this study is to identify psychopathology (psychiatric symptoms) that can
      differentiate between Schizotypal Disorder (SD) and Asperger Syndrome (normal IQ, no language
      impairment Autism Spectrum Disorder) (AS) in young adults.

      With our present knowledge, the differentiation between AS and SD can be difficult, as they
      both present with social difficulties, odd (but not psychotic) behaviour, and a 'feeling of
      not being as everyone else'. Studies suggest that adults with AS symptoms are either
      overlooked, or diagnosed within the schizophrenia spectrum in Adult Psychiatry.

      A 'correct' diagnosis is important, as it is the first step towards the most optimal plan,
      treatment and rehabilitation for the patient. The only way to diagnose psychiatric illness is
      the description of present psychopathology.

      To identify symptoms that can differentiate between the two disorders, we will use
      semi-structured interviews to explore present psychopathology in young adults with typical
      symptoms of SD and AS respectively, with special focus on presence of alterations in
      self-experience. Alterations in self-experience are typical for the schizophrenia spectrum,
      and are therefore not thought to be equally present in AS and SD.

      The hypotheses are that the total level of altered experiences is higher in SD, than in AS,
      and with a different pattern of altered experiences in SD than in AS. If the hypotheses are
      true, an examination of altered self-experience will be valuable to aid clinical
      differentiation between the two disorders.
    

Detailed description: 
      Background: SD is a non-psychotic disorder within the Schizophrenia Spectrum (in ICD-10), and
      has a prevalence of 3.9 % in adult samples. Autism Spectrum Disorder (ASD), a pervasive
      developmental disorder (including AS), has a prevalence of 1 %.

      SD is typically diagnosed in young adults, whereas AS typically is diagnosed in childhood.
      Sometimes however, the AS symptoms first become invalidating in young adulthood, where social
      demands exceed the individual's capacity. In these cases, patients with symptoms
      corresponding to AS, might first be diagnosed as young adults. In Adult Psychiatry though,
      experience with diagnosing ASD is scarce, and studies suggest that adult patients presenting
      with symptoms corresponding to AS, are either overlooked, or diagnosed within the
      schizophrenia spectrum.

      Psychiatric diagnosis: Description of present psychopathology is the only way to diagnose
      psychiatric illness. An accurate diagnosis is crucial for a relevant treatment and
      rehabilitation plan for the individual patient, as the diagnosis guides the help and support
      offered. Further, to properly guide neuro-psychiatric research, high diagnostic accuracy is
      imperative. This study will refer to the diagnostic criteria defined in ICD-10, when
      including participants, as ICD-10 is the principal diagnostic system in Denmark.

      Altered self-experience: Alterations in self-experience are considered highly specific for
      the schizophrenia spectrum, and are therefore not thought to be present in equal amounts
      and/or distribution in ASD. If this is true, an examination of anomalous self-experiences
      would be valuable to aid clinical differentiation between SD and AS. For patients with
      altered self-experience, the experience of him-/herself as a subject is disturbed. This means
      that the form and structure (rather than content) of the patients' thoughts and experiences
      is altered.

      Aim, objectives and hypotheses: The aim is to do an in depth exploration of differences in
      present psychopathology (psychiatric symptoms) in young adults with SD and AS. This will
      elaborate and refine our understanding of SD and AS specifically, and ASD and schizophrenia
      spectrum disorders in general.

      The objectives are to; 1. Explore differences in psychopathology between young adults with SD
      and AS and, 2. Contribute to both the general and the specific (in SD and AS respectively)
      description of the autism concept.

      The hypotheses are that; 1. The total level of altered experiences (EASE total score) is
      higher in SD than in AS and, 2. The pattern of most occurring altered experiences (individual
      EASE items) is different in AS, compared to SD.

      Material and methods: The study is observational and comparative in design, and will include
      100 participants; 50 diagnosed with SD, and 50 with AS. The included subjects medical history
      will be revised by two senior psychiatric consultants, ensuring identification of
      participants with typical symptoms. Further, all included participants will be assessed with
      three semi-structured psychopathological interviews, general symptom and functional scores
      and self-reports.

      Co-ratings: All study interviews will be videotaped, and a subset of the taped SCAN and EASE
      interviews will be co-rated within the research group. Co-ratings will also routinely be
      performed amongst psychologists at The Danish Autism Centre, who conducts the ADOS
      interviews.

      Statistical analyses: To investigate between group differences, group wise comparisons
      between SCAN algorithms, ADOS algorithms and EASE outcomes will be applied. Further,
      secondary correlations across psychopathological domains will be explored, and explorative
      cross-diagnostic factor analysis will be performed.

      Ethical considerations: Prior to inclusion a differentiated informed consent will be obtained
      from all participants.
    

Intervention name(s): Expert panel evaluation; Semi-structured psychopathological interviews; Self-administered rating scales; Other general interviewer ratings
Intervention type(s): Other; Other; Other; Other
Intervention description(s): From the medical records, described social and psychiatric history and observed psychiatric symptoms will be summarized and presented to two senior psychiatric consultants. The panels evaluation ensures the identification of subjects with typical symptoms, according to a best estimate clinical consensus.
The panel divides the participants into 4 groups: 'participant with symptoms typical of AS', 'participant with symptoms typical of SD', 'participant with inconclusive/non typical symptoms' and 'non eligible participant'.; Included participants are asked for a detailed social and developmental history and interviewed with 3 semi-structured interviews: 1. Schedules for Assessment in Neuropsychiatry (SCAN); Covering psychopathology and behaviour associated with the major psychiatric disorders. 2. Autism Diagnostic Observation Schedule (ADOS), module 4; An assessment to identify symptoms within the autism spectrum. 3. Examination of anomalous self-experience (EASE); A checklist for exploration of experiential anomalies. The Ph.D.-student will obtain social and developmental history and carry out SCAN and EASE interviews. ADOS will be carried out by a consultant psychologist at The Danish Autism Centre.; 1.The Autism Quotient (AQ), a 50 question scale, for the assessment of autistic traits, 2. The Schizotypal Personality Questionnaire (SPQ), a 74 item scale, for the assessment of schizotypal personality, 3. The WHO-5 Well-Being Index (WHO-5), a 5 item scale, for the assessment of subjective psychological well-being.; 1. Global Assessment of Functioning (GAF), a numeric scale (1 through 100) for assessing social, occupational, and psychological functioning, 2. The Clinical Global Impressions scale (CGI-Severity), an assessment of the clinician's global view of the patient's severity of psychopathology on a 7 point scale.
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Only already diagnosed participants are recruited, from specialised units. This is
        essential, as inclusion of participants with typical symptoms, reduces confounding of the
        results by diagnostic uncertainty.

        Participants with SD will be recruited from OPUS-teams (a specialized treatment program for
        patients with first episode of schizophrenia spectrum disorder), within the Mental Health
        Services in the Capitol Region of Denmark, and participants with AS from The Danish Autism
        Centre (a non-profit organization for people with ASD).
      
Keywords: Asperger Syndrome; Autism Spectrum Disorder; Schizotypal disorder; Schizophrenia Spectrum Disorder; Psychopathology; Examination of Anomalous Self Disorder; Autism Diagnostic Observation Schedule; Phenomenology; Differential diagnosis; Young Adult