Age at onset of non-affective psychosis in relation to cannabis use, other drug use and gender.

BACKGROUND: Cannabis use is associated with an earlier age at onset of psychotic illness. The aim of the present study was to examine whether this association is confounded by gender or other substance use in a large cohort of patients with a non-affective psychotic disorder. METHOD: In 785 patients with a non-affective psychotic disorder, regression analysis was used to investigate the independent effects of gender, cannabis use and other drug use on age at onset of first psychosis. RESULTS: Age at onset was 1.8 years earlier in cannabis users compared to non-users, controlling for gender and other possible confounders. Use of other drugs did not have an additional effect on age at onset when cannabis use was taken into account. In 63.5% of cannabis-using patients, age at most intense cannabis use preceded the age at onset of first psychosis. In males, the mean age at onset was 1.3 years lower than in females, controlling for cannabis use and other confounders. CONCLUSIONS: Cannabis use and gender are independently associated with an earlier onset of psychotic illness. Our findings also suggest that cannabis use may precipitate psychosis. More research is needed to clarify the neurobiological factors that make people vulnerable to this precipitating effect of cannabis.

[Women, schizophrenia and oestrogen; neurobiological hypotheses and hormonetherapy studies]. / Vrouwen, schizofrenie en oestrogeen; neurobiologische hypothesen en interventiestudies.

BACKGROUND: Gender differences play a role in the origin and course of schizophrenia. It has been hypothesised that the gonadal hormone, oestrogen, may possibly perform a protective function in the development of certain forms of schizophrenia. AIM: To review neurobiological hypotheses concerning the role of oestrogen in the development and course of schizophrenia. METHOD: The relevant literature was consulted with the help of PubMed, textbooks and bibliographic references; the search terms used were 'oestrogen', 'schizophrenia', 'gender', 'epigenetics', 'psychosis', 'women' and 'brain'. There were no restrictions with regards to the time-period. RESULTS: Neuro-imaging, animal experiments and hormone-therapy studies showed several effects of oestrogen in the field of epigenetics, morphology of the brain, interaction with neurotransmitters and neuroprotection. CONCLUSION: Oestrogen is an important link in a complex of factors that clearly play a role in the varying development of schizophrenia in men and women. So far, however, there is insufficient evidence to support the existence of a specific mechanism that would explain why oestrogen may perform a protective function in schizophrenia.

Reasons for cannabis use and effects of cannabis use as reported by patients with psychotic disorders.

BACKGROUND: Cannabis is one of the most commonly used substances in patients with a psychotic disorder and is associated with a higher risk of psychotic relapses. Identifying reasons for cannabis use and subjective effects in patients with psychotic disorders can provide insight into the functions of cannabis use, and this may lead to targeted interventions. METHODS: A literature search of the PubMed and PsycINFO databases for articles published from 1985 till 2008 was carried out to review studies that examined self-reported reasons for cannabis use and self-reported effects of cannabis use in patients with psychotic disorders. RESULTS: Only a few studies were found that specifically assessed reasons for and effects of cannabis use. Despite the heterogeneity in the study samples and methodology, patients commonly reported that their reasons for cannabis use were enhancement of positive affect, relief of dysphoria and social enhancement. Fewer patients reported reasons related to relief of psychotic symptoms or relief of side effects of medication. Frequently reported positive effects of cannabis were positive changes in affect and relaxation. A large proportion of patients reported that cannabis negatively affected positive symptoms. CONCLUSIONS: Patients suffering from psychotic disorder report using cannabis mainly for affect regulation and socialization, despite the awareness that cannabis has a negative effect on positive symptoms. In spite of the heterogeneity of the studies, the results turned out to be broadly comparable and support the external validity of this review to a broad range of cannabis-using patients with psychotic disorder.

[Is there any point in detecting high risk factors prior to a first psychosis?]. / Wanneer heeft detectie van hoogrisicofactoren voor een eerste psychose zin?

BACKGROUND: If schizophrenia and related disorders are diagnosed and treated early, symptoms will be less severe and the prognosis will be more favourable. There is little point in screening for schizophrenia in the general population because the illness has such a low incidence. However, we do need to find out whether it is meaningful to screen genetically impaired individuals (high risk group) and specific groups of psychiatric patients (ultra high risk group). AIM: To survey the research into the (high and ultra high) risk factors for developing a first psychosis and to find out whether it makes good sense to screen certain groups of persons. METHOD: We conducted extensive desk-research and a wide-ranging search of the literature from 1990 to 2004. The key words we used in our search were 'prodrome', 'high risk', 'ultra high risk', in conjunction with 'psychosis' and 'schizophrenia'. RESULTS: In the genetically impaired group risk factors for developing schizophrenia seem to be transient psychiatric problems in childhood, schizotypical traits, anxiety, behavioural problems in adolescence, being brought up in an unstable environment and producing deviant results in neurocognitive tests. Among the patients referred to a psychiatrist it is possible to identify a special group of patients with an ultra high risk of developing a psychosis. Within ayear 40% of patients who had mild or short-term psychotic symptoms or who were genetically impaired adolescents with decreased functioning had developed a psychosis. CONCLUSION: Screening all genetically vulnerable persons in the general population has no consequencesfor treatment. Early diagnosis by psychiatrists is certainly advisable. However, larger groups and longer studies are needed in order to demonstrate conclusively the preventive effect of interventions prior to a first psychosis.