Figure 2. Meta-analysis of older antidepressants compared with newer antidepressants for major depression in adults. N indicates number of participants; n indicates number of studies. HT = hydroxy-tryptophan; MAOI = monoamine oxidase inhibitor; NRI = norepinephrine reuptake inhibitor; RIMA = reversible inhibitor of monoamine oxidase A; SSRI = selective serotonin reuptake inhibitor; SNRI = serotonin and noradrenaline reuptake inhibitor; TCA1 = first-generation tricyclic antidepressant; TCA2 = second-generation tricyclic antidepressant.