Clinical characteristics of psychosis in HIV infection have been described, but there have been limited comparative studies in HIV-endemic low-resource regions.

To compare clinical characteristics of psychosis in HIV-positive and HIV-negative patients at the main psychiatric referral units in Uganda.

Patients with psychosis were consecutively recruited and completed a standardised demographic questionnaire and psychiatric and laboratory assessments including an HIV test. The Mini International Neuropsychiatric Interview was used to diagnose psychiatric illness. Psychosis symptoms were compared between HIV-positive and HIV-negative individuals using bivariate methods. A logistic regression model was used to assess the effects of age, gender and HIV status on different types of psychosis.

There were 478 patients enrolled, of which 156 were HIV positive and 322 were HIV negative. The mean age was 33.2 years (95% CI 31.8–34.5) for the HIV-positive group and 29.6 years (95% CI 28.7–30.5) for the HIV-negative group (P < 0.001). Female patients had a higher proportion of seropositivity 40.6% (95% CI 34.8–46.4) compared with males 21.8% (95% CI 16.1–27.5) (P < 0.001). Psychotic disorder not otherwise specified occurred more in the HIV-positive individuals (88% (95% CI 82.9–93.1) v. 12% (95% CI 8.4–15.5), P < 0.001). Motor activity, irritability, emotional withdrawal, feelings of guilt, mannerisms and posturing, grandiosity, suspiciousness, unusual thoughts, blunted affect, excitement and disorientation were associated with HIV seropositivity.

The presentation of psychosis in patients with HIV is unique to this HIV endemic setting. Characterisation of the symptomatology of patients presenting with psychosis is important for proper diagnosis and care.

For complex multifactorial diseases it seems likely that co-exposure to two risk factors will show a greater than additive relationship on disease risk.

To test whether greater than additive relationships occur between risk factors for psychosis.

A cohort study of 50 053 Swedish conscripts. Data on IQ, cannabis use, psychiatric diagnoses, disturbed behaviour and social relations assessed at age 18 were linked to admissions with any non-affective psychoses over a 27-year follow-up period. Statistical interactions between risk factors were examined under both additive and multiplicative models.

There was some evidence of interaction for eight of the ten combinations of risk factors under additive models, but for only one combination under multiplicative models.

Multiplicative models describe the joint effect of risk factors more adequately than additive ones do. However, the implications of finding interactions as observed here, or for most interactions reported to date, remain very limited.

Some studies suggest that cannabis use is associated with suicidal ideation, but no detailed longitudinal study has examined suicide as an outcome.

To examine the association between cannabis use and completed suicide.

A longitudinal study investigated 50 087 men conscripted for Swedish military service, with cannabis use measured non-anonymously at conscription. Suicides during 33 years of follow-up were identified by linkage with the National Cause of Death Register.

There were 600 (1.2% of cohort) suicides or deaths from undetermined causes. Cannabis use was associated with an increased risk of suicide (crude OR for ‘ever use’ 1.62, 95% CI 1.28–2.07), but this association was eliminated after adjustment for confounding (adjusted OR = 0.88, 95% CI 0.65–1.20).

Although there was a strong association between cannabis use and suicide, this was explained by markers of psychological and behavioural problems. These results suggest that cannabis use is unlikely to have a strong effect on risk of completed suicide, either directly or as a consequence of mental health problems secondary to its use.

Previously reported associations between advancing paternal age and schizophrenia could be due to an increase in paternal germ cell mutations or be confounded by heritable personality traits associated with schizophrenia that result in delayed parenthood.

To investigate this association while adjusting for personality traits related to poor social integration in the subjects.

A cohort of 50 087 adolescent males was followed up by record linkage to determine hospital admissions for schizophrenia between 1970 and 1996.

Advancing paternal age was associated with an increased risk of developing schizophrenia in a ‘dose-dependent’ manner. The adjusted odds ratio for each 10-year increase in paternal age was 1.3 (95% Cl 1.0–1.5; P=0.015).

Advancing paternal age is an independent risk factor for schizophrenia. Adjusting for social integration in subjects made little difference to this association, consistent with the hypothesis that advancing paternal age may increase liability to schizophrenia owing to accumulating germ cell mutations.

Previous research has found an association between obstetric complications and schizophrenia, but in many studies the sample size was limited, and no assessment of specific exposures was possible.

To assess the role of different complications, and in particular to distinguish between disordered foetal development and hypoxia at birth.

From the Stockholm County In-Patient Register and community registers, we identified 524 cases of schizophrenia and 1043 controls, matched for age, gender, hospital and parish of birth. Data on obstetric complications were obtained from birth records.

There was a strong association between signs of asphyxia at birth and schizophrenia (OR 4.4; 95% C11.9–10.3) after adjustment for other obstetric complications, maternal history of psychotic illness and social class.

Signs of asphyxia at birth are associated with an increased risk of schizophrenia in adults.

Obstetric complications have been studied frequently as possible risk factors for schizophrenia.

To test the hypotheses that individual obstetric complications are most strongly associated with an increased risk of schizophrenia in males, in patients with an early age at first diagnosis and in subjects with a maternal history of psychosis.

Cases of schizophrenia diagnosed between January 1971 and June 1994 were identified in the Stockholm County In-Patient Register. Controls were matched on age, gender, hospital of birth and parish of birth. Obstetric data were recorded blind to case–control status for 524 cases and 1043 controls.

This study did not find any large or consistent effect of gender, age at diagnosis or maternal history of psychosis on the risk of schizophrenia associated with individual complications.

Future studies should examine these effects using a much larger sample that includes patients with schizophrenia and control subjects whose genetic risk of schizophrenia has been assessed accurately.

Those with schizophrenia often give a history of premorbid non-psychotic psychiatric disorder.

To investigate the association between non-psychotic psychiatric disorders and the later development of schizophrenia.

Men aged 18 or 19 years, conscripted to the Swedish army in 1970 (n=50 054) were linked to the Swedish National Psychiatric Case Register.

There was an increased risk of schizophrenia in those with ICD–8 diagnoses of neurosis (OR=4.6,95% CI 3.2–6.9), personality disorder (OR=8.2, 95% CI 5.4–12.3), alcohol abuse (OR=5.5, 95% CI 1.7–17.5) or substance abuse (OR=14.0, 95% CI 7.8–25.0) at age 18. Of those who developed schizophrenia, 38% (95% CI 32–45) received a diagnosis of non-psychotic psychiatric disorder at age 18. Only those with personality disorder had a significantly increased risk of schizophrenia (OR=2.4, 95% CI 1.1–5.2) with onset after age 23.

Personality factors could represent an underlying vulnerability to schizophrenia. Other diagnoses occurring before schizophrenia may reflect a prodromal phase of the illness.

Women take sick-leave more often than men, both in general and because of psychiatric disorders. The aim of the present study was to introduce the new dimension of sick-leave duration in the analysis of gender differences in minor psychiatric disorders.

A population-based register was used which included all sick-leave spells exceeding seven consecutive days, 1985–1987, in a Swedish county.

Sick-leave duration was longer for men. The greatest gender differences were found in the youngest and oldest age-groups. Women had higher incidence also in the longest spells. An increase in duration over the three years was found among women, leading to decreased gender differences.

Contrary to other studies on minor psychiatric disorders, small gender differences were found. It is suggested that sick-leave duration can be used as a quantitative measure of health-related working capacity.