Thomas F. McNeil

Substance abuse in schizophrenia: a review of the literature and a study of correlates in Sweden

The purpose of the current study is twofold: (a) to provide an overall synthesis of recent research on substance abuse in schizophrenia and (b) to present findings in a Swedish patient sample. Studies conducted since 1990 have found a wide range of abuse prevalence rates, with male gender and younger age as primary correlates. Less certainty exists regarding substance abuse as an independent risk factor for schizophrenia and its further impact on illness course. In a sample of 87 patients attending a psychiatric clinic in Malmö, lifetime prevalence of substance abuse was 48.3%, with abuse debut primarily preceding first contact for psychotic symptoms. Significant correlates of abuse were male gender, family history of substance abuse, and increased rates of hospitalization and criminality, with poorer outcome found in previous as well as current abusers. Alcohol abuse, either solely or in combination with other substances, was the main type of substance abuse. Although the specific factors (social, behavioural, genetic) that predispose schizophrenic patients to substance abuse remain unclear, the predominantly male profile of abusers might suggest a link between substance abuse and the poorer clinical outcome frequently observed, especially in male schizophrenic patients.

Increased rates of psychosis among immigrants to Sweden: is migration a risk factor for psychosis ?

BACKGROUND Previous studies have shown high rates of psychosis among Afro-Caribbean immigrants to the UK and immigrants to the Netherlands. Rates of schizophrenia-like psychoses (SLP), i.e. schizophrenia or other non-affective psychosis, among the native-born and immigrant populations were assessed in Malmö, the city in Sweden with the highest proportion of immigrants. METHODS All adult patients admitted for in-patient psychiatric treatment in Malmö during the course of a 1-year period (N = 1162) were studied with regard to ethnicity and SLP diagnosis. A smaller sample consisting only of first-onset SLP cases (regardless of in- or out-patient status) was also studied (N = 56). Risks for admission and first-onset were calculated on the basis of current background population figures for Malmö. RESULTS Compared with those who were native-born, immigrants had increased risk for admission for SLP, with a similar tendency for increased risk for first-onset of SLP. Relative risk for SLP admission was most markedly increased in immigrants from East-Africa. Background factors specifically associated with migration (e.g. extreme duress) did not appear to contribute strongly to SLP in immigrants. CONCLUSION While the current results add to the growing body of evidence showing increased risk for psychosis in immigrants, vulnerability to psychosis may have been determined by factors other than the migration process.

Obstetric complications as antecedents of schizophrenia: Empirical effects of using different obstetric complication scales

The new McNeil-Sjöström Scale for obstetric complications (OCs), as well as scales of Lewis et al. (Schizophrenia: Scientific progress. Oxford University Press, 1989) and Parnas et al. (British Journal of Psychiatry, 140, 416-420, 1982), were applied to the OC histories of 70 singleton schizophrenics and 70 demographically-matched controls from the same hospital delivery series, using blindly assessed hospital pregnancy and birth record information. With the McNeil-Sjöström scale, schizophrenics were found to have significantly increased rates of OCs for the total reproduction, as well as for labor-delivery and the neonatal period but not for pregnancy. Significant increases in OCs in these schizophrenics were also found in scores produced by the Lewis et al. scale but not by the Parnas et al. scale. Further application of these three scales to OC data obtained through parental report for 23 monozygotic (MZ) twin pairs discordant and 10 pairs concordant for schizophrenia, as well as seven normal control MZ pairs, showed a significant difference in OC rates across the different twin pair groups, when assessed by the McNeil-Sjöström and Parnas et al. scales, but not by the Lewis et al. scale. The particular scoring system used in a study is thus of considerable importance not only for findings concerning OC histories of schizophrenics vs. controls, but also for the relationship between OCs and other presumed etiological factors in schizophrenia. Among the three scales, the McNeil-Sjöström scale provided the most sensitive assessment of OC history for schizophrenics.

Paternal and maternal age as risk factors for psychosis: findings from Denmark, Sweden and Australia

BACKGROUND While the association between increased maternal age and congenital disorders has long been recognized, the offspring of older fathers are also at increased risk of congenital disorders related to DNA errors during spermatogenesis. Recent studies have drawn attention to an association between increased paternal age and increased risk of schizophrenia. The aim of the current study was to examine both paternal and maternal age as risk factors for the broader category of psychosis. METHOD We used data from three sources examining psychosis: a population-based cohort study (Denmark), and two case-control studies (Sweden and Australia). RESULTS When controlling for the effect of maternal age, increased paternal age was significantly associated with increased risk of psychosis in the Danish and Swedish studies. The Australian study found no association between adjusted paternal age and risk of psychosis. When controlling for the effect of paternal age, younger maternal age was associated with an increased risk of psychoses in the Danish study alone. CONCLUSIONS The offspring of older fathers are at increased risk of developing psychosis. The role of paternally derived mutations and/or psychosocial factors associated with older paternal age warrants further research.

A prospective study of postpartum psychoses in a high-risk group: I. Clinical characteristics of the current postpartum episodes

Abstract— Postpartum psychotic episodes (PPPs) occurring during the first 6 months after delivery were prospectively studied in 88 pregnant index women with a history of nonorganic psychosis and 104 pregnant controls with no such history. While no control developed a PPP, PPPs were found following 28% of the index deliveries, almost all of these 25 cases being psychiatrically hospitalized. PPPs were especially frequent among cases with total illness diagnoses of Cycloid Psychosis and Affective Illness. More than half of the 25 cases had symptom onset within 3 weeks of delivery, and these early onset cases represented predominantly affective disorders, many of whom were manic in this episode. Cases with onset after 3 weeks were predominantly schizophrenic. Confusion was part of the current episode symptomatology in about one third of the cases and was well distributed across the different diagnostic groups.

Minor physical anomalies in schizophrenia: Cognitive, neurological and other clinical correlates

Minor physical anomalies (MPAs) are minor congenital malformations which are found with significantly increased frequency among both patients with schizophrenia and their siblings, suggesting the effect of early developmental disturbance in their families. The aim of this study was to explore the relationship between these signs of early dysmorphogenesis and cognitive and neurological dysfunction in the patients and their siblings as well as the clinical characteristics of the patients. Sixty patients with schizophrenia, 21 nonpsychotic siblings and 75 normal comparison subjects were studied. Increased rates of cognitive and neurological dysfunction and high MPA scores were found in both the patients and their siblings. High rates of MPAs were not significantly related to cognitive or neurological dysfunction in the patients or siblings, or to premorbid history or other characteristics of the clinical disease process in the patients. These results suggest that MPAs are possibly markers of general early neuromaldevelopment rather than markers of a specific cognitive/neurological or clinical subtype of schizophrenia.

A prospective study of postpartum psychoses in a high-risk group. 2. Relationships to demographic and psychiatric history characteristics.

ABSTRACT— Among 88 reproductions to women with a history of nonorganic psychosis, 25 postpartum episodes (PPPs) occurring during the total 6‐month period following the current delivery were not systematically related to the womans demographic characteristics, to her psychiatric history characteristics surrounding onset of the previous disorder or to a history of PPPs following previous reproductions. PPPs were highly significantly related to greater length of previous psychiatric hospitalization and to active mental disturbance just prior to this pregnancy, and this was true both for PPPs developing within 3 weeks of delivery and for those developing later. Considerable differences were found in the demographic characteristics that were related to development of PPPs within these Early vs. Later Onset cases, suggesting these to represent different disorders not only diagnostically but also demographically. In several diagnostic categories, selected demographic or psychiatric history characteristics identified subgroups with PPP rates as high as 75%.

Increased rates of schizophrenia among immigrants: some methodological concerns raised by Danish findings.

BACKGROUND Several studies during recent years have reported an increased occurrence of schizophrenia in selected immigrant groups. However, difficulties in establishing the population denominator for immigrant rates of mental disorder, selective referral for treatment, and other problems may have influenced such results. The current study aims at testing empirically the influence of some of these methodological problems. METHODS Using nationwide case register data from Denmark, the diagnosis specific first-admission rates were compared between persons born in Denmark and other countries respectively. A case-control design was used to compare schizophrenia risk between different immigrant groups. RESULTS Incidence rates of mental disorders among non-Danish residents calculated from admission data showed increased rates of schizophrenia (RR 1.7) and non-affective functional psychoses (RR 1.9). A case-control analysis utilizing non-psychotic admissions as control for schizophrenic admissions yielded essentially the same result, thus excluding selective referral as the sole explanation of the increased schizophrenia rate. However, this was almost exclusively due to increased rates in individuals born in countries neighbouring on Denmark. CONCLUSIONS While selective risk factors may be operating in various groups of immigrants, caution should be warranted in the interpretation of immigrant studies as large portions of transient visitors may obscure actual rates of mental disorders.

Obstetric complications in histories of monozygotic twins discordant and concordant for schizophrenia

Histories of obstetric complications (OCs) during pregnancy, labor‐delivery and the neonatal period were investigated by detailed maternal report for 23 monozygotic (MZ) twin pairs discordant for schizophrenia, 10 MZ twin pairs concordant for schizophrenia and 7 normal MZ control pairs. Statistically significant differences in OC rates were found across these 3 groups, OCs being most frequent in discordant pairs and least frequent in normal control pairs. Labor complications were significantly more frequent in discordant than concordant pairs. Oc rates were equivalent in sick and well discordant twins. The results provide evidence for the role of OCs in the development of schizophrenia, complications at the time of birth being especially associated with the development of schizophrenia in discordant twins.

Offspring of women with nonorganic psychoses. Development of a longitudinal study of children at high risk.

ABSTRACT– This article describes the development of a prospective, longitudinal study of 88 “high‐risk” offspring of pregnant index women with a history of nonorganic psychoses and 104 offspring of demographically‐similar pregnant control women. The maternal psychoses represented the diagnostic categories, Schizophrenia, Cycloid Psychosis, Affective Illness, Psychogenic Psychosis, Postpartum Psychosis and Other (remaining) Psychoses. The first phase of the study began during pregnancy and continued until the offspring reached 2 years of age. Selected characteristics of the mothers, the offspring and their environments were investigated during this project phase.