Subject(s)
Colonic Neoplasms/classification , Colonic Neoplasms/therapy , Rectal Neoplasms/classification , Rectal Neoplasms/therapy , Chemoradiotherapy, Adjuvant , Chemotherapy, Adjuvant , Colonic Neoplasms/diagnosis , Colonic Neoplasms/pathology , Humans , Neoadjuvant Therapy , Neoplasm Staging , Rectal Neoplasms/diagnosis , Rectal Neoplasms/pathologyABSTRACT
OBJECTIVE: Obsessive-compulsive symptoms (OCS) frequently occur in psychotic disorders. Cross-sectional associations between OCS and cognitive impairment have led to different causal explanations. Whereas one assumes that higher cognitive impairment reflects a risk factor for psychotic patients to develop OCS, another suggests that deficits reflect a consequence of OCS. This study investigated the longitudinal interrelation between OCS and cognitive functioning. METHOD: Baseline and follow-up data from 622 patients and 670 un-affected siblings from the 'Genetic Risk and Outcome in Psychosis' study were analyzed. Participants were allocated to groups according to the presence or absence of OCS at assessments and compared on several cognitive domains. RESULTS: Cross-sectional comparisons revealed no group differences in cognitive performance. Longitudinal analyses comparing the groups with changes in OCS revealed one significant group effect with more problems in set-shifting abilities in patient who reported OCS development at follow-up. Significant time and interaction effects were mainly due to improvement in immediate verbal recall and digit-symbol coding in patients and siblings who reported remission of OCS. CONCLUSION: Although insight into causality needs further exploration, our results do not confirm the hypothesis of pre-existing cognitive risk constellations. Findings suggest that remission of comorbid OCS results in improved immediate verbal recall and processing speed.
Subject(s)
Cognition Disorders/physiopathology , Executive Function/physiology , Mental Recall/physiology , Obsessive-Compulsive Disorder/physiopathology , Psychomotor Performance/physiology , Psychotic Disorders/physiopathology , Adolescent , Adult , Cognition Disorders/epidemiology , Comorbidity , Cross-Sectional Studies , Female , Humans , Longitudinal Studies , Male , Middle Aged , Obsessive-Compulsive Disorder/epidemiology , Psychotic Disorders/epidemiology , Siblings , Young AdultABSTRACT
BACKGROUND: In recent years quantitative genetic research has addressed all the major psychiatric disorders. In order to interpret the results of this type of research one needs to be aware of its potential and its limitations. AIM: To discuss the basic concepts and the main results of quantitative genetic research and to consider how this can help us to better understand the aetiology of psychiatric disorders. METHODS: Using Medline (1990-February 2006) we reviewed the literature on the subject of quantitative genetic and psychiatric disorders. In addition we studied the standard books on the subject. RESULTS: A fairly large number of psychiatric disorders, namely about 30 to 85%, can be inherited. In addition, the non-shared environment has a considerable influence on the phenotype. The influence of the shared environment seems to have only a limited influence or it is totally absent. The results of quantitative genetic research are specific to a particular time or environment and therefore may not be applicable to other populations. There may be a correlation or interaction between genetic factors and the environment while the phenotype is being formed. However, because of the analytical methods used, this is only partly visible in the results. CONCLUSION: Quantitative genetic research has made an impressive contribution to our knowledge about the heritability of psychiatric disorders. By definition quantitative genetic research always provides information about environmental influences.
