Impact of Cannabis Use on Treatment Outcomes among Adults Receiving Cognitive-Behavioral Treatment for PTSD and Substance Use Disorders.
BACKGROUND
Research has demonstrated a strong link between trauma, posttraumatic stress disorder PTSD and substance use disorders (SUDs) in general and cannabis use disorders in particular. Yet, few studies have examined the impact of cannabis use on treatment outcomes for individuals with co-occurring PTSD and SUDs.


METHODS
Participants were 136 individuals who received cognitive-behavioral therapies for co-occurring PTSD and SUD. Multivariate regressions were utilized to examine the associations between baseline cannabis use and end-of-treatment outcomes. Multilevel linear growth models were fit to the data to examine the cross-lagged associations between weekly cannabis use and weekly PTSD symptom severity and primary substance use during treatment.


RESULTS
There were no significant positive nor negative associations between baseline cannabis use and end-of-treatment PTSD symptom severity and days of primary substance use. Cross-lagged models revealed that as cannabis use increased, subsequent primary substance use decreased and vice versa. Moreover, results revealed a crossover lagged effect, whereby higher cannabis use was associated with greater PTSD symptom severity early in treatment, but lower weekly PTSD symptom severity later in treatment.


CONCLUSIONS
Cannabis use was not associated with adverse outcomes in end-of-treatment PTSD and primary substance use, suggesting independent pathways of change. The theoretical and clinical implications of the reciprocal associations between weekly cannabis use and subsequent PTSD and primary substance use symptoms during treatment are discussed.
Department of Psychology, The City College of New York, CUNY, 160 Convent Avenue, NAC Building, Rm 7/120, New York, NY 10031, USA. ruglass.ccny@gmail.com.
Lesia M
LM
Ruglass
Department of Psychology, Pace University, 861 Bedford Road, Pleasantville, NY 10570, USA. alina.shevorykin@gmail.com.
Alina
A
Shevorykin
Gordon F. Derner Institute for Advanced Psychological Studies, Adelphi University, IAPS, Hy Weinberg Center, Room 306, Garden City, NY 11530-0701, USA. vanyaradoncic@gmail.com.
Vanja
V
Radoncic
Division on Substance Use Disorders, Department of Psychiatry, Columbia University Medical Center/New York State Psychiatric Institute, 1051 Riverside Drive, Box 66, New York, NY 10032, USA. k.m.zumberg@gmail.com.
Kathryn M Z
KM
Smith
Sophie Davis School of Biomedical Education, The City College of New York, 160 Convent Avenue, New York, NY 10031, USA. psmith@med.cuny.edu.
Philip H
PH
Smith
Department of Psychiatry, NYU School of Medicine, 1 Park Avenue, New York, NY 10016, USA. isaac.galatzer-levy@nyumc.org.
Isaac R
IR
Galatzer-Levy
Department of Psychology and Institute for Mental Health Research, University of Texas, Austin, 108 E. Dean Keeton Street, Austin, TX 78712, USA. papinisan@gmail.com.
Santiago
S
Papini
Gordon F. Derner Institute for Advanced Psychological Studies, Adelphi University & Department of Psychiatry, Columbia University College of Physicians and Surgeons, Hy Weinberg Center, Room 306, Garden City, NY 11530-0701, USA. dr.denise.hien@gmail.com.
Denise A
DA
Hien
PTSD; cannabis; substance use disorder; trauma; treatment outcomes