Three studies totalling 147 participants (107 adults and 40 adolescents) met the inclusion criteria. Seventy-four participants took part
in DMT treatment, while 73 comprised the control groups. Two studies included male and female adults with depression. One of
these studies included outpatient participants; the other study was conducted with inpatients at an urban hospital. The third study
reported findings with female adolescents in a middle-school setting. All included studies collected continuous data using two different
depression measures: the clinician-completed Hamilton Depression Rating Scale (HAM-D); and the Symptom Checklist-90-R (SCL-
90-R) (self-rating scale).
Statistical heterogeneity was identified between the three studies. There was no reliable effect of DMT on depression (SMD -0.67 95%
CI -1.40 to 0.05; very low quality evidence). A planned subgroup analysis indicated a positive effect in adults, across two studies, 107
participants, but this failed to meet clinical significance (SMD -7.33 95% CI -9.92 to -4.73).
One adult study reported drop-out rates, found to be non-significant with an odds ratio of 1.82 [95% CI 0.35 to 9.45]; low quality
evidence. One study measured social functioning, demonstrating a large positive effect (MD -6.80 95 % CI -11.44 to -2.16; very low
quality evidence), but this result was imprecise. One study showed no effect in either direction for quality of life (0.30 95% CI -0.60
to 1.20; low quality evidence) or self esteem (1.70 95% CI -2.36 to 5.76; low quality evidence).