PM519. Early Cannabis Use Effects on Frontal Cortical Gamma Oscillations in First Episode Psychosis

Background: Individuals at ultra-high risk (UHR) for psychosis are understood to be the putative prodrome of overt psychosis, although there is still a possibility of false positives. The aim of the present study is to examine the potential links between multi-dimensional schizotypy, basic symptoms and emerging psychosis as defined by positive symptoms in individuals at ultra-high risk (UHR) for psychosis. Method: Sixty-one UHR individuals and 41 healthy controls were participated in baseline assessments. For multi-dimensional schizotypy assessments, Chapman’s perceptual aberration scale, magical ideation scale, revised physical and social anhedonia scales, schizotypal ambivalence scales, and Eysenck’s impulsiveness scale were used. Basic symptoms were assessed by using the schizophrenia-specific items of the Frankfurt complaints questionnaire (FCQ). Results: Individuals at UHR showed higher schizotypy scores and basic symptoms at baseline. The transition rate of overt psychosis was 36.4 % at 4 years of follow-up. Cox regression analysis showed that the basic symptoms (HR 1.456, p = 0.025) and impulsiveness (HR 1.175, p = 0.039) were significant predictors of transition into overt psychosis in UHR individuals [χ2(4) =14.242, p = 0.007]. Conclusion: The addition of the self-reported basic symptoms and impulsiveness may be useful for a risk enhancement or stratification strategy in individuals at ultra-high risk for psychosis. Acknowledgement: This study was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI14C2242). PM518 Medication Adherence in schizophrenia: Focus on therapeutic relationship Jhin-Goo Chang1, Daeyoung Roh1, Chan-Hyung Kim1,2* 1Department of Psychiatry and Institute of Behavior Science in Medicine, Yonsei University College of Medicine, Seoul, Korea 2Department of Psychiatry, College of Medicine, Hallym University,