There is concern that selective serotonin reuptake inhibitor (SSRI) treatment may increase the risk of suicide attempts or deaths, particularly among children and adolescents. However, debate remains regarding the nature of the relationship. Using nationwide Swedish registers, we identified all individuals aged 6–59 years with an incident SSRI dispensation (N = 538,577) from 2006 to 2013. To account for selection into treatment, we used a within-individual design to compare the risk of suicide attempts or deaths (suicidal behaviour) in time periods before and after SSRI-treatment initiation. Within-individual incidence rate ratios (IRRs) of suicidal behaviour were estimated. The 30 days before SSRI-treatment initiation was associated with the highest risk of suicidal behaviour compared with the 30 days 1 year before SSRI initiation (IRR = 7.35, 95% CI 6.60–8.18). Compared with the 30 days before SSRI initiation, treatment periods after initiation had a reduced risk—the IRR in the 30 days after initiation was 0.62 (95% CI 0.58–0.65). The risk then declined over treatment time. These patterns were similar across age strata, and when stratifying on history of suicide attempts. Initiation with escitalopram was associated with the greatest risk reduction, though CIs for the IRRs of the different SSRI types were overlapping. The results do not suggest that SSRI-treatment increases the risk for suicidal behaviour in either youths or adults; rather, it may reduce the risk. Further research with different study designs and in different populations is warranted.

有人担心选择性5-羟色胺再摄取抑制剂（SSRI）治疗可能会增加自杀未遂或死亡的风险，尤其是在儿童和青少年中。然而，关于这种关系的性质仍然存在争议。使用瑞典全国登记册，我们确定了所有年龄在 6-59 岁之间的个体 SSRI 分配（N = 538,577）从 2006 年到 2013 年。为了考虑到治疗的选择，我们使用个体内部设计来比较 SSRI 治疗开始之前和之后时间段内的自杀企图或死亡（自杀行为）风险。估计了自杀行为的个体内发生率比（IRR）。与 SSRI 开始前 1 年的 30 天相比，SSRI 治疗开始前 30 天与自杀行为的最高风险相关（IRR = 7.35, 95% CI 6.60-8.18）。与 SSRI 开始前 30 天相比，开始后的治疗期风险降低——开始后 30 天的 IRR 为 0.62（95% CI 0.58-0.65）。然后风险随着治疗时间的推移而下降。这些模式在不同年龄层和按自杀未遂史分层时是相似的。尽管不同 SSRI 类型的 IRR 的 CI 重叠，但开始使用依他普仑与最大的风险降低相关。结果并不表明 SSRI 治疗会增加青少年或成人自杀行为的风险；相反，它可能会降低风险。有必要对不同的研究设计和不同的人群进行进一步的研究。