Symptomatology and neuropsychological functioning in cannabis using subjects at ultra-high risk for developing psychosis and healthy controls.

OBJECTIVE: The relationship between cannabis use and psychosis has been studied intensively. Few data, however, are available on the relationship between cannabis use, ultra-high risk for developing psychosis and neurocognition. The aim of the present cross-sectional study was therefore to investigate the relationship between cannabis use, ultra-high-risk (UHR) symptoms and cognitive functioning in UHR patients and healthy controls. METHODS: A total of 63 ultra-high-risk patients (34 cannabis users) and 58 control subjects (28 cannabis users) were assessed with clinical measures and a neuropsychological test battery. Patients were eligible for the study if they were between the ages of 12 and 35 years and if they fell into one or more of the following inclusion groups: familial risk and reduced functioning, attenuated psychotic symptoms, brief limited intermittent psychotic symptoms and basic symptoms. Control subjects were eligible for the study if they were between the ages 12 and 35, had no present or past psychiatric illness, no family history of psychiatric illness, no drug use in the non-cannabis-using group, and use of at least four joints per week in the cannabis-using control group. RESULTS: In the UHR and the control group, cannabis users experienced more basic symptoms and UHR symptoms than the non-cannabis users. Moreover, cannabis users in the control group performed at the level of the UHR subjects on a test of verbal memory and verbal fluency. Frequency of cannabis use correlated with severity of several UHR symptoms. CONCLUSIONS: Cannabis-using UHR patients have more basic symptoms than non-using patients. In addition, healthy cannabis users have more subclinical UHR and basic symptoms and more neuropsychological dysfunctions than non-cannabis users. More frequent cannabis use was related to increased severity of certain UHR symptoms.

Obsessive-compulsive symptoms in patients with schizophrenia: a naturalistic cross-sectional study comparing treatment with clozapine, olanzapine, risperidone, and no antipsychotics in 543 patients.

OBJECTIVE: To compare the prevalence of obsessive-compulsive symptoms (OCS) in a population of patients with schizophrenia taking clozapine, olanzapine, or risperidone or taking no antipsychotic medication. METHOD: Baseline data of the Genetic Risk and Outcome of Psychosis study were collected between April 2005 and October 2008. We conducted a naturalistic cross-sectional study of 543 patients with schizophrenia and related disorders, who were recruited from multiple mental health centers, including inpatient and outpatient clinics, across The Netherlands. The patients met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria and were taking no antipsychotic medication or taking clozapine, olanzapine, or risperidone. OCS severity was measured with the Yale-Brown Obsessive Compulsive Scale. We compared patients to a sample of 575 healthy controls. RESULTS: Prevalence of OCS in patients was significantly higher than in the control sample, 23.4% versus 4.9% (χ(2) = 73.8, P < .001). Patients taking clozapine reported OCS significantly more often during the last week (38.9%), when compared to patients taking olanzapine (20.1%, χ(2) = 10.02, P = .002) or risperidone (23.2%, χ(2) = 5.96, P = .015) and patients taking no antipsychotics (19.6%, χ(2) = 8.20, P = .004). Patients taking clozapine for 6 months or longer reported OCS significantly more often than patients taking clozapine for less than 6 months, 47.3% versus 11.8% (χ(2) = 6.89, P = .009). CONCLUSIONS: Treatment with clozapine in patients with schizophrenia is associated with a higher prevalence of OCS, especially when patients have been taking clozapine for 6 months or longer. We cannot rule out the possibility that this association is related to illness characteristics. Patients treated with risperidone or olanzapine or without treatment with antipsychotic medication had comparable prevalence of OCS, all significantly higher than the control sample.

Genetic Risk and Outcome of Psychosis (GROUP), a multi-site longitudinal cohort study focused on gene-environment interaction: objectives, sample characteristics, recruitment and assessment methods.

OBJECTIVE: A longitudinal focus on gene-environment vulnerability and resilience in both patients, their unaffected family members and non-related controls offers the opportunity to elucidate etiological and pathogenetic factors influencing the onset and course of psychotic disorders. The current paper delineates the objectives, sample characteristics, recruitment and assessment procedures of the Genetic Risk and Outcome of Psychoses (GROUP) study. METHODS: A naturalistic longitudinal cohort study with assessments at baseline, after three and six years of follow-up. The study is conducted by a consortium of four university psychiatric centres, with their affiliated mental health care institutions in the Netherlands covering more than 7.5 million inhabitants. Extensive assessment of genetic factors, environmental factors, (endo)phenotypes, and outcome. RESULTS: At baseline, 1120 patients, 1057 siblings, 919 parents and 590 healthy controls were included. CONCLUSION: The GROUP study will contribute to insight in risk and protective factors in the aetiology of non-affective psychotic disorders, and in the variation in their course and outcome.