Thirty-two adult males with an ASD were recruited via local mental health organizations (mainly through the specialized Autism Team North Netherlands of Lentis, Groningen, the Netherlands), and through mailing lists for high-functioning individuals with ASD. Six individuals with ASD were recruited from a local forensic clinic (FPC Dr. S. van Mesdag, Groningen, the Netherlands). The participants were considered to be high-functioning by their clinicians and none had an IQ score below 70. All participants were diagnosed with an ASD by a clinical psychologist or psychiatrist according to DSM-IV-TR criteria (n = 8 AD, n = 17 AS, n = 13 PDD-NOS), based on review of developmental history, current daily functioning, and observation. For this study, the ASD group will be investigated as one diagnostic entity along a continuous dimension of severity for two reasons. First, it is proposed for the near future that distinctions will no longer be made among different types of autism in clinical practice, because they have proven to be “inconsistent over time and place, and to be associated more with severity, language level, and intelligence than specific features” (www.dsm5.org ). Individuals with autism and PDD-NOS have also shown qualitatively similar behavioral patterns on the ADOS with varying degrees of severity (Lord et al. 2000 (link)). Second, investigating the subtypes would lead to overly small subgroups.
Eighteen adult males with schizophrenia and predominantly negative symptomatology, mainly outpatients, were selected by a specialized local mental health organization (Psychosencluster, GGZ Drenthe, Assen, the Netherlands). Diagnosis was confirmed by a structured clinical interview, the Dutch version of the Schedules of Clinical Assessment in Neuropsychiatry developed by the WHO (SCAN 2.1, Giel and Nienhuis 1996 ). Current symptomatology was assessed by the Positive and Negative Syndrome Scale (PANNS, Kay et al. 1987 (link)).
The psychopathy group consisted of 16 males recruited from two forensic psychiatric clinics (FPC Dr. S. van Mesdag and FPC Veldzicht). As part of the standard clinical procedure, these individuals were assessed with the Psychopathy Checklist Revised (PCL-R), an instrument widely used for the diagnosis of psychopathy (e.g. Hare 1991 ). Two diagnosticians obtained consensus on this instrument after separately scoring the items using file information extended with, if necessary, a semi-structured interview.
The typically developing group consisted of 21 typically developing males, who were interviewed to verify that first-degree relatives did not have an ASD or a history of psychosis. Age and IQ was matched with the participants with ASD who also took part in the neuroimaging part of the study (n = 21). There are no significant differences between the groups in terms of age and IQ. For an overview of the group characteristics see Table1 .
Eighteen adult males with schizophrenia and predominantly negative symptomatology, mainly outpatients, were selected by a specialized local mental health organization (Psychosencluster, GGZ Drenthe, Assen, the Netherlands). Diagnosis was confirmed by a structured clinical interview, the Dutch version of the Schedules of Clinical Assessment in Neuropsychiatry developed by the WHO (SCAN 2.1, Giel and Nienhuis 1996 ). Current symptomatology was assessed by the Positive and Negative Syndrome Scale (PANNS, Kay et al. 1987 (link)).
The psychopathy group consisted of 16 males recruited from two forensic psychiatric clinics (FPC Dr. S. van Mesdag and FPC Veldzicht). As part of the standard clinical procedure, these individuals were assessed with the Psychopathy Checklist Revised (PCL-R), an instrument widely used for the diagnosis of psychopathy (e.g. Hare 1991 ). Two diagnosticians obtained consensus on this instrument after separately scoring the items using file information extended with, if necessary, a semi-structured interview.
The typically developing group consisted of 21 typically developing males, who were interviewed to verify that first-degree relatives did not have an ASD or a history of psychosis. Age and IQ was matched with the participants with ASD who also took part in the neuroimaging part of the study (n = 21). There are no significant differences between the groups in terms of age and IQ. For an overview of the group characteristics see Table
Group characteristics
N | Mean | Stdev | Range | |
---|---|---|---|---|
ASD | ||||
Age | 38 | 31.82 | 11.24 | 18–66 |
IQ | 29 | 101.14 | 14.67 | 73–133 |
Schizophrenia | ||||
Age | 18 | 37.00 | 10.73 | 19–61 |
IQ | 18 | 89.17 | 13.89 | 68–112 |
Psychopathy | ||||
Age | 16 | 39.00 | 10.67 | 23–60 |
IQ | 15 | 92.73 | 16.10 | 63–117 |
Controls | ||||
Age | 21 | 34.24 | 9.14 | 21–53 |
IQ | 21 | 97.19 | 16.37 | 73–128 |
IQ scores were based on the Groninger Intelligence Test 2 (GIT2, Luteijn and Barelds 2004 ), except for four individuals with ASD who were administered the Wechsler Adult Intelligence Scale (WAIS, Wechsler 1997 ) and nine individuals with ASD for whom IQ scores were not obtained (they only took part in the ADOS part of the research project). For these cases, IQ was estimated to be in the normal range based on former IQ tests and clinical impression/daily functioning. GIT 2 scores for one individual with psychopathy were deemed unreliable and discarded