Methods: PLEs, dissociative symptoms, and sleep quality were examined in 1,677 undergraduate students using self- report measures. A mediation analysis using PROCESS was performed to examine whether dissociative experiences can account for some of the relationship between sleep quality and PLEs. Results: Dissociative symptoms significantly mediated the relationship between sleep quality and PLEs, with both age and gender used as covariates, CI: [.1513, .2840]. Conclusions: These findings suggest that dissociation may be a key contributor to the relationship between disrupted sleep and PLEs, which could have treatment and identification implications. Supported By: This work was funded by CLA Research Award, Temple University, Philadelphia, PA (L.M.E.), a start-up grant awarded to L.M.E., and the National Institute of Mental Health (MH096478, Principal Investigator L.M.E.). Keywords: Early Psychosis, Sleep, Dissociation F248. Suicidal Behaviors and Non-Suicidal Self-Harm in a Schizophrenia Sample Joshua DeSon 1 , Rebecca Fortgang 2 , Zoe Owrutsky 3 , Karen Berman 1 , and Dwight Dickinson 4 1 National Institute of Mental Health, 2 Yale University, 3 University of Colorado, 4 National Institutes of Health Background: Lifetime risk of completed suicide and suicide attempts are high in people with schizophrenia. We assessed the prevalence and predictors of suicidal behaviors in a large sample of living schizophrenia cases and tested the associa- tions of non-suicidal self-injury (NSSI), mood disorder, suicidal ideation, and suicide attempts. Methods: Data on suicidal behaviors were abstracted from medical records in 570 participants diagnosed with schizophrenia or schizoaffective disorder. We used logistic regression analyses to study the relationships among NSSI, presence of mood disorder symptoms, suicidal ideation, and suicide attempts. All analyses controlled for age, sex, and race. Results: We found a history suicidal ideation in medical re- cords for 73.2% of participants and of suicidal attempts in 43.4%. Suicidal ideation significantly predicted attempt (p¼5.1E-11, OR¼4.4). Presence of a mood disorder was a stronger predictor of suicidal ideation (p¼6.9E-09, OR¼ 3.2) than was NSSI (p¼0.04, OR¼1.6). However, NSSI was a stronger predictor of actual suicide attempt (p¼9.631E-09, OR¼3.1) than were mood disorders (p¼.001, OR¼1.8). When mood disorders, suicidal ideation, and NSSI were modeled together, ideation (p¼7.6E-09, OR¼3.9) and NSSI (p¼ 6.9E-08, OR¼3.0) were independent predictors of attempts, whereas mood disorders were not (p¼.074, OR¼1.4). Conclusions: Suicidal ideation and attempts are highly prevalent in our sample. While mood symptoms are generally viewed as critical predictors of suicide attempts, our data reaffirms that suicidal ideation mediates the relationship be- tween mood disorders and attempts. Perhaps indicative of a separable impulsivity risk dimension, NSSI predicted attempts independently of ideation and mood. Supported By: NIH Intramural Research Program Keywords: Schizophrenia, Schizoaffective Disorder, Non- Suicidal Self-Injury, Suicide Attempts, Suicidal Ideation F249. Sleep Quality, Psychological Symptoms, and Psychotic-Like Experiences Arielle Ered 1 , Shanna Cooper 1 , and Lauren Ellman 1 1 Temple University Background: Poor sleep quality has been repeatedly linked to the entire psychosis continuum, including psychotic-like ex- periences (PLEs); however, sleep dysfunction is a component of several other psychopathologies that have also been linked to increased risk for PLEs, including depression, anxiety, and post-traumatic stress disorder (PTSD). It has yet to be exam- ined if PLEs are a significant risk factor for poor sleep quality or if this sleep dysfunction is better accounted for by comorbid psychopathology. Methods: In 2,687 undergraduates, PLEs were evaluated using the positive items of the Prodromal Questionnaire. Symptoms of anxiety, depression, and PTSD were also assessed, as was sleep quality. Mediation analysis using PROCESS was conducted to determine if poor sleep quality associated with PLEs was in fact more associated with symptoms of other psychopathologies. Results: Symptoms of depression and PTSD mediated the relationship between PLEs and sleep quality [CIs¼ .0277 - .0498 and .0451 - .0718, respectively], though anxiety symp- toms did not [CI¼ -.0161 - .0063]. Conclusions: These findings suggest that treating symptoms of depression and PTSD may improve multiple domains of psychotic illness. Supported By: This work was funded by CLA Research Award, Temple University, Philadelphia, PA (L.M.E.), a start-up grant awarded to L.M.E., and the National Institute of Mental Health (MH096478, Principal Investigator L.M.E.). Keywords: Early Psychosis, Trauma, Depression, Anxiety, Sleep F250. Increased Dopamine Synthesis Capacity in the Ventral Striatum of Patients With Chronic Schizo- phrenia During Psychotic Remission Mihai Avram 1 , Felix Brandl 1 , Jorge Cabello 1 , Mona Mustafa 1 , Sibylle Ziegler 2 , and Christian Sorg 1 1 Technical University Munich, 2 Technical University Munich, University Hospital, LMU Munich Background: Striatal presynaptic dopamine synthesis ca- pacity, as measured by 18fluoro-levo-dihydroxyphenylalanine positron emission tomography (18F-DOPA-PET), is increased in patients with schizophrenia, and has been suggested to be associated with psychosis. However, the majority of Poster Abstracts Biological Psychiatry May 1, 2018; 83:S129eS455 www.sobp.org/journal S335 Biological Psychiatry