Abstract: We included four studies (188 participants). Two studies were double-blind RCTs, one was a non-randomised controlled trial, and one was an observational retrospective case-matched study. The age of participants ranged from 27 to 37.8 years. In three studies participants had quiescent IBD and in one study participants had active or quiescent IBD. Participants in one study had co-morbid anxiety or depression. One study used duloxetine (60 mg daily), one study used fluoxetine (20 mg daily), one study used tianeptine (36 mg daily), and one study used various antidepressants in clinical ranges. Three studies had placebo controls and one study had a no treatment control group. One RCT was rated as low risk of bias and the other was rated as high risk of bias (incomplete outcome data). The non-randomised controlled trial was rated as high risk of bias (random sequence generation, allocation concealment, blinding). The observational study was rated as high methodological quality, but is still considered to be at high risk of bias given its observational design. The effect of antidepressants on anxiety and depression is uncertain. At 12 weeks, the mean anxiety score in antidepressant participants was 6.11 + 3 compared to 8.5 + 3.45 in placebo participants (MD -2.39, 95% -4.30 to -0.48, 44 participants, low certainty evidence). At 12 months, the mean anxiety score in antidepressant participants was 3.8 + 2.5 compared to 4.2 + 4.9 in placebo participants (MD -0.40, 95% -3.47 to 2.67, 26 participants; low certainty evidence). At 12 weeks, the mean depression score in antidepressant participants was 7.47 + 2.42 compared to 10.5 + 3.57 in placebo participants (MD -3.03, 95% CI -4.83 to -1.23, 44 participants; low certainty evidence). At 12 months, the mean depression score in antidepressant participants was 2.9 + 2.8 compared to 3.1 + 3.4 in placebo participants (MD -0.20, 95% -2.62 to 2.22, 26 participants; low certainty evidence). The effect of antidepressants on AEs is uncertain. Fifty-seven per cent (8/14) of antidepressant participants group reported AEs versus 25% (3/12) of placebo participants (RR 2.29, 95% CI 0.78 to 6.73, low certainty evidence). Commonly reported AEs include nausea, headache, dizziness, drowsiness, sexual problems, insomnia, fatigue, low mood/anxiety, dry mouth, muscle spasms and hot flushes. None of the included studies reported any serious AEs. None of the included studies reported on pain. One study (44 participants) reported on QoL at 12 weeks and another study (26 participants) reported on QoL at 12 months. Physical, Psychological, Social and Environmental QoL were improved at 12 weeks compared to placebo (all low certainty evidence). There were no group differences in QoL at 12 months (all low certainty evidence). The effect of antidepressants on maintenance of clinical remission and endoscopic relapse is uncertain. At 12 months, 64% (9/14) of participants in the antidepressant group maintained clinical remission compared to 67% (8/12) of placebo participants (RR 0.96, 95% CI 0.55 to 1.69; low certainty evidence). At 12 months, none (0/30) of participants in the antidepressant group had endoscopic relapse compared to 10% (3/30) of placebo participants (RR 0.14, 95% CI 0.01 to 2.65; very low certainty evidence). The results for the outcomes assessed in this review are uncertain and no firm conclusions regarding the efficacy and safety of antidepressants in IBD can be drawn. Future studies should employ RCT designs, with a longer follow-up and develop solutions to address attrition. Inclusion of objective markers of disease activity is strongly recommended as is testing antidepressants from different classes, as at present it is unclear if any antidepressant (or class thereof) has differential efficacy.

Plain-language summary: The researchers searched the medical literature up to 23 August 2018. Four published studies, including a total of 188 people, examined antidepressant therapy in people with IBD. The age of participants ranged from 27 to 37.8 years. In three studies participants had IBD in remission and in one study participants had either active IBD or IBD in remission. Participants in one study had co-existing anxiety or depression. One study used duloxetine (60 mg daily), one study used fluoxetine (20 mg daily), one study used tianeptine (36 mg daily), and one study used various antidepressants. Three studies had a placebo (e.g. sugar pill) control group and one study had a no treatment control group. The analysis showed that the symptoms of anxiety and depression were improved in those who took antidepressants compared to placebo. Participants who received antidepressants experienced more side effects than those who received placebo. Side effects reported by those taking antidepressants included: nausea, headache, dizziness, drowsiness, sexual problems, insomnia, fatigue, low mood/anxiety, dry mouth, poor sleep, restless legs and hot flushes. Some aspects of quality of life were improved as was IBD activity in the antidepressant group. The overall quality of the studies included in this review was poor because the studies included small numbers of participants, and involved IBD populations which differed from each other on key characteristics. In addition, different types of antidepressants were assessed so the evidence for any one antidepressant was uncertain. Therefore, future studies are needed to confirm these observations. The results for the outcomes assessed in this review are uncertain and no firm conclusions regarding the benefits and harms of antidepressants in IBD can be drawn. More studies are needed to allow for firm conclusions regarding the benefits and harms of the use of antidepressants in people with IBD.