The effect licit and illicit drugs have on trauma processing and memory

Preliminary research suggests that depressant drugs such as alcohol may represent a protective factor against developing Post-traumatic Stress Disorder (PTSD), and stimulant drugs such as methamphetamine and methylenedioxymthamphetamine (MDMA) a risk factor for the development of PTSD. Based on this preliminary research, the current study explored the effect alcohol, methamphetamine and MDMA had on trauma processing and memory. Sixty-one healthy adults participated in a double-blind, placebo controlled crossover design containing three conditions that involved the consumption of either 0.42mgt/kg of d-methamphetamine, 100mg of MDMA, 1.3 grams/kg of alcohol or placebo in a randomised order. The procedure used to measure affective processing and memory was the immediate and delayed recall and recognition performance following completion of the Lexical Decision Task (LDT) and International Affective Picture System (IAPS) Task. The results supported some of the hypotheses formulated with regards to the effect alcohol and methamphetamine would have on emotional processing and storage of traumatic stimuli. The results did not support the hypotheses formulated with regards to the effect MDMA would have on emotional processing and storage of traumatic stimuli. Alcohol alters affective reactions to traumatic stimuli, reducing arousal levels and impairing threat estimation. Alcohol also has an inhibiting effect on the memory systems responsible for the storage and retrieval of such stimuli. Methamphetamine consumption appears to increase visual memory for emotional stimuli in general, but may impair short-term memory for verbally stored trauma-related stimuli, while enhancing long-term memory for such stimuli. MDMA consumption may temporarily improve short-term memory for traumarelated stimuli, but appears to reduce long-term visual and verbal memory. The effect appears specific to threat-related visual stimuli with memory for emotional stimuli in general remaining intact. The methodology implemented in the study was unable to truly simulate the presentation of traumatic stimuli, and the dose of stimulants used was probably lower than is consumed in recreational use. The study indicates that alcohol is a significant protective factor against later developing PTSD after exposure to a trauma. Whilst the trends in the data indicate that methamphetamine may pose a risk for later developing PTSD, the low power levels of the sample were unable to confirm if these effects were significant. The effect MDMA has on the risk of later developing PTSD is mixed and appears to have a minimal impact. The results of the current study should prompt continued research into the role trauma processing and memory play in the pathogenesis of PTSD.