The Effects of Postnatal Maternal Cannabis Use on Infant Temperament Rex Chan1, Jackie Finik1,2, Rejina Daniel1, Benjamin Reissman1, and Yoko Nomura, Ph.D.1,2 1Department of Psychology, Queens College, City University of New York, 65-30 Kissena Blvd Flushing NY 11367 2Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029 Abstract Results Objective: To measure the impact of postnatal maternal cannabis use on infant temperament at M=25.29 months of age. Method: Postnatal maternal cannabis use within six months of assessment was collected via maternal self-report using the Cannabis Use Disorder Identification Test (CUDIT-R). Infant temperament was assessed via the Early Childhood Behavior Questionnaire (ECBQ) via self-report by mothers. Results: Significant differences were found in discomfort (p=.007), frustration (p=.024), and repetitive small-motor activities (p=.003) in children of mothers with postnatal cannabis use as compared to children of mothers who did not report postpartum cannabis use. Conclusion: Postnatal cannabis use had a significant adverse effect on infant temperament on dimensions of discomfort, frustration, and motor activity. Discomfort (p=.007), frustration (p=.024), and motor activation (p=.003) temperament scores were significantly higher in infants of mothers with cannabis use within the last six months of assessment as compared to those without. Postnatal Cannabis Use and Infant Temperament Scales 4.68 4.06 3.62 3.70 3.16 2.57 Aim & Background Aim: To investigate the effects of postnatal maternal cannabis use on infant temperament. Previous research suggested that cannabis use before and during pregnancy has significant adverse effects on child motor, cognitive, and behavioral development, (i.e. externalizing problems) (Marroun, 2010).  We hypothesized that offspring of mothers who used cannabis postnatally (within 6 months of follow-up) would have significantly different mean temperament scores on scales related to motor activity, and emotional regulation. Discomfort: The amount of negative affect related to sensory qualities of stimulation Frustration: Negative affect related to disruption of current tasks or goal blocking Motor Activation: Small repetitive motor movements, such as fidgeting Postnatal Cannabis Use and Infant Temperament Scales Measures Sample Population: 89 mothers (n=100) were recruited to participate in a longitudinal study of pregnancy (SIP Study, P.I. Yoko Nomura). Measures: Cannabis Use Disorder Identification Test (CUDIT-R) was used to assess for cannabis use within the past six months via self-report. At postpartum (M=25.29 months), participants were given the Early Childhood Behavior Questionnaire (ECBQ), which prompted mothers to rate their infant’s temperament and behavior along 18 scales, 15 of which were used due to missing data (Activity Level/Energy, Attention Focusing, Attention Shifting, Cuddliness, Discomfort, Fear, Frustration, High-intensity Pleasure, Inhibitory Control, Low-intensity Pleasure, Motor Activation, Perceptual Sensitivity, Sadness, Shyness, and Soothability). Data Analysis: A one-way ANOVA was conducted to test whether children of mothers who used cannabis postnatally had significant differences on mean temperament scores. Discussion The present research indicates a significant association between postnatal maternal cannabis use and child discomfort, frustration, and motor activation. While not significant, postnatal cannabis use also adversely affected attention focusing, fear, inhibitory control, sadness, and soothability of infants. Negative temperament is related to distressed based psychopathology and influences the course of depression (Watson & Clark, 1995). Postnatal maternal cannabis use can lead to negative temperament, which may then increase offspring risk for psychiatric disorders. Greater awareness of the negative impact of prenatal and postpartum cannabis use is needed to mitigate the prevalence of maternal cannabis use, which may in turn aid in preventing negative temperament outcomes in high risk offspring. Acknowledgements: This work was supported in part by the NIMH K01-080062; R01MH102729 (P.I. Yoko Nomura). Thank you to Mount Sinai Hospital and NYHQ’s Ob/Gyn and L&D staff. Thank you to the families who participated in this study. References: Astley, S. J., & Little, R. E. (1990). Maternal marijuana use during lactation and infant development at one year. Neurotoxicology and teratology, 12(2), 161-168. El Marroun, H. (2010). Prenatal Cannabis Exposure and Infant Development:“A Tolerated Matter”. Watson, D., & Clark, L. A. (1995). Depression and the melancholic temperament. European Journal of Personality, 9(5), 351-366. Maternal Groups