Tetrahydrocannabinol (THC) and cannabidiol (CBD) are phytocannabinoids being linked with modulation of anxiety and depression. The recognition of emotions in facial expressions (REFE) is impaired in these disorders. Both drugs could modulate anxiety and mood by interfering with REFE. Thus, a systematic review of controlled trials assessing the effects of THC and CBD on REFE was performed. Ten studies describing seven distinct experiments were found (n = 170). THC (7.5-15 mg) did not alter REFE in three experiments, but reduced task performance in other three experiments. CBD did not alter REFE in two experiments, but improved task performance and counteracted the effects of THC in one experiment. THC (≥ 10 mg) and CBD (600 mg) showed opposite effects on brain activation, skin conductance, and anxiety measures with negative/threatening faces. The limited number of studies precludes firm conclusions on the effects of these substances on REFE. Further controlled trials are needed to elucidate the effects of THC and CBD on REFE. The PROSPERO ID for this study is CRD42019135085.

四氢大麻酚（THC）和大麻二酚（CBD）是植物性大麻素，与焦虑和抑郁的调节有关。在这些疾病中，面部表情（REFE）中的情绪识别受到损害。两种药物都可以通过干扰REFE来调节焦虑和情绪。因此，对评价THC和CBD对REFE的影​​响的对照试验进行了系统评价。发现了十项描述七个不同实验的研究（n = 170）。THC（7.5-15 mg）在三个实验中没有改变REFE，但是在其他三个实验中却降低了任务表现。在两个实验中，CBD并没有改变REFE，但是在一个实验中，CBD改善了任务性能并抵消了THC的影响。THC（≥10毫克）和CBD（600毫克）对大脑活动，皮肤电导和焦虑/消极面对威胁措施的效果相反。有限的研究排除了关于这些物质对REFE的影​​响的确切结论。需要进一步的对照试验以阐明THC和CBD对REFE的影​​响。该研究的PROSPERO ID为CRD42019135085。