A Replication Study

Research has found that Obsessive Compulsive Symptoms (OCS) in schizophrenia are associated with either more or less negative symptoms and either better or poorer cognitive functioning. In order to explain these contradictory results, Lysaker et al.(Lysaker et al., 2004), performed a cluster analysis resulting in 2 OCS positive (OCSpos) clusters, one with higher functioning (HF) and one with poorer functioning (PF) compared to 2 OCS negative (OCSneg) clusters. The OCSpos/HF cluster had less negative symptoms compared to all other clusters, while the OCSpos/PF cluster showed poorer executive functioning. We performed a replication study, in an almost 10 times larger, representative sample, using both a longitudinal and cross-sectional design. Similar to Lysaker et al., we found a group with mild OCS and HF (OCSmild/HF) showing less negative symptoms compared to the PF groups. We also found an OCSmild/PF group, which did not significantly differ in executive functioning from the other groups. Moreover, we did not find evidence for a better prognosis in the OCSmild/HF group, and thus found no support for the assumption that for some patients OCS might be an effective coping mechanism. without OCS using cluster analysis. In line with their findings, our primary hypotheses are a) that patients in the OCSpos/PF group will show poorer executive functioning and sustained attention and more negative symptoms than any other group and b) that patients in the OCSpos/HF group will show lower levels of negative symptoms compared to the poor functioning groups. Furthermore, in a longitudinal approach we will evaluate whether proposed differences in cognitive domains and negative between will remain present at 3 year follow-up. As Lysaker et al. (2004) suggested in their discussion: “research employing longitudinal assessments shed more light on question if subgroups Stability of outcome will favour this hypothesis. More specifically, we will test c) cognitive at remain stable at 3-year follow-up. CPT omission and commission scores and the DSC task, corrected for significant covariates and using Bonferroni correction. Release 5.0 of the GROUP database was used for the analyses. groups were lost at follow-up. These results do not support the hypothesis that the OCSmild/HF group would show a milder course of illness, expressed by a consistent low score of negative symptom severity at follow-up or any other symptom domains. Hence we did not find evidence for the proposed possibility by Lysaker et al. (2004) that the presence of a group with OCS and better functioning, despite equivalent levels of neurocognitive function might suggest that OCS “have some protective function for persons with schizophrenia who do not have severe neurocognitive deficits”. Since the study of Lysaker et al. (2004) has been published, an increasing number of studies has investigated the association between the presence of comorbid OCS and functioning. Several findings have suggested a possible dual impact of OCS on functioning, with mild OCS being associated with better functioning and severe OCS with poorer functioning (de Haan et al., 2013; Tonna et al., 2016a, b). However, Kontis et al., (2016) found a positive association between OCS and social functioning, independent of cognitive functioning and the severity of OCS (Kontis et al., 2016). Other recent studies indicated a negative association with social and vocational functioning, even with relatively mild OCS severity (Schirmbeck et al., 2016b) or no associations (Grover et al., 2017). In line with these inconsistent findings, our cluster analyses results in two groups with mild OCS severity, one with relatively good social functioning and one with relatively poor social functioning. Furthermore, the group with high OCS severity showed moderate function. Hence, we cannot draw general conclusions on the association between the presence of comorbid OCS severity and implications on social functioning, associated clinical impairment or implications for the prospective course. Both cluster analyses suggest that different subgroups of comorbid patients exists, those with high and those with lower social functioning. Apart from associations with negative symptoms, future studies should further investigate possible underlying factors, including a more comprehensive assessment of different cognitive domains, dosage of antipsychotic This study is a replication study of a cluster analyses conducted by Lysaker et al. (2004) in a large representative sample of patients with psychotic disorders. The orinigal study found four subgroups of patients with schizophrenia according to the presence of comorbid OCS and the level of social functioning (Lysaker et al., 2004). When chosing a 5-cluster solution the current study identified similar subgroups, including a group with OCS and relatively poor social functioning and a group with OCS and relatively high social functioning. In line with Lysaker et al., the group with OCS and high functioning showed less negative symptoms compared to the groups with poor functioning. However, these differences did not persist at 3-year follow-up. Furthermore, although the large sample provided sufficient statistical power we were not able to replicate that the group with OCS and poorer social functioning showed higher deficits in executive functioning or sustained attention compared to the other groups. Taken together, our results support the assumption that co-morbid OCS can have different implications for different subgroups of patients with psychotic disorders. In some patients OCS seem to be associated with less severe other problems. However, we did not find evidence for a benificial course of illness in this group. Future prospective studies are needed to investigate stability of proposed clusters and apply broader assessment of associated clinical variables. work