Cannabis use and age at onset of psychosis: further evidence of interaction with COMT Val158Met polymorphism.

OBJECTIVE: To examine, in a sample of young psychiatric patients, (n = 157, mean age 17.01 years (SD = 3.6)) whether i) age at first cannabis use and age at emergence of psychiatric disorders are related and ii) such a relationship is modulated by the Val158Met polymorphism in the COMT gene. METHOD: Cannabis use profiles and COMT Val158Met genotypes were obtained from 80 inpatients with schizophrenia-spectrum disorders and 77 inpatients with other non-psychotic disorders. RESULTS: First, age at first cannabis use correlates with age at onset in both schizophrenia-spectrum and other psychiatric disorder groups: those who started using cannabis earlier had an earlier age at onset of psychiatric disorders. Second, the distribution of the Val158Met genotypes was not different either between diagnosis groups or between cannabis users and non-users. Third, an interaction between Val158Met genotypes and cannabis use was observed specifically on age at emergence of psychotic disorders, with Val/Val genotype carriers showing an earlier age at onset than Met carriers. CONCLUSION: Our results suggest the importance of brain maturation timing in which exposure to cannabis occurs. The COMT Val158Met genotype seems to modulate the association between cannabis and age at onset of psychotic disorders. These results are consistent with previous studies.

[Design and validation of a complex case evaluation index].

BACKGROUND: The aim was to develop and validate the Complex Case Assessment Index (CCAI), a specific instrument to identify complex patients. METHODS: Instrumental study in two phases: 1) Development of the scale: the variables extracted from the literature were firstly defined and operationalized, and then submitted for expert judgment. The CCAI included 14 variables divided into two dimensions: complexity of clinical management and complexity of community management. 2) Psychometric study: evaluation of the reliability and validity of the scale by equivalence between observers (Pearson's r), criterion validity with respect to the Clinical Risk Groups (CRG) classification system, and construct validity through known groups and study of hierarchical clusters were examined. The analyses were carried out with the SPSS version 17 statistical package. RESULTS: Reliability by equivalence between observers was r?=?0.97 for the clinical subscale, r?=?0.74 for the community subscale, and r?=?0.89 for the total score. The CCAI identified 518 cases as complex; 458 of them (88.4%) were categorized by the CRG system in the categories of greatest clinical complexity (levels 6 to 9). The results support the construct validi-ty of the scale. The cluster analysis showed two different, although related, clusters. CONCLUSION: The CCAI is a fast and easy-to-use index, with good conceptual adequacy and evidence of reliability and validity for screening patients with complex needs.