Hazy memories: the impact of drugs on false memory formation from a legal-psychopharmacological perspective

In many criminal cases, no physical evidence is available, so that legal decision-making has to rely strongly on the testimonies of witnesses, victims, and suspects. However, individuals involved in crime are often intoxicated with drugs, such as alcohol, cannabis, or MDMA (ecstasy). These drugs have long been known to interfere with memory by increasing forgetfulness, but there is little knowledge about whether they also heighten the occurrence of false memories – so remembering events or details that did not happen. Across one literature review and four experimental studies, it was assessed whether drug intoxication, especially with cannabis and MDMA, can increase the susceptibility to false memories. Cannabis use was consistently linked to higher false memories, especially during acute intoxication, which has important implications for legal, forensic, and clinical settings. MDMA intoxication was found to increase forgetting but did not heighten false memories. In sum, the thesis concluded that a nuanced approach is needed when dealing with intoxicated persons in the legal system, because differences between drugs exist in how memory for a crime is affected.