The literature on the effect of psychotherapy for schizophrenia is limited and characterized by small samples and possible bias from risk selection. We examined the effects of psychotherapy on suicide attempts and health and economic outcomes using an instrumental variable (IV) approach that exploits the variation in the propensities of hospital departments to prescribe psychotherapy. This was supplemented with naïve probit models as exogeneity could not be ruled out for all of the outcomes. The validity of the instrument was examined by distributional plots and various tests. The assumed randomness in referring patients to providers with high versus low propensities to psychotherapy appeared to be a critical aspect. Splitting the sample into homogeneous provider types did not substantially alter the results. Based on the IV results, we found no support for the effect of psychotherapy on suicide attempt, psychiatric readmission, assisted living, or labor market attachment. However, we cannot rule out smaller effects due to confidence intervals including the probit estimates. The main contribution of this study is new evidence on a broad range of outcomes and a large and representative population.

中文翻译：

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基于工具变量评估心理治疗对精神分裂症自杀企图、健康和经济结果的影响

关于精神分裂症心理治疗效果的文献有限，其特点是样本量小，风险选择可能存在偏差。我们使用工具变量 (IV) 方法研究了心理治疗对自杀企图以及健康和经济结果的影响，该方法利用了医院科室开出心理治疗处方的倾向的变化。由于不能排除所有结果的外生性，因此辅以朴素概率模型。该工具的有效性通过分布图和各种测试来检验。将患者转介给心理治疗倾向高或低的提供者时假设的随机性似乎是一个关键方面。将样本分成同质的提供者类型并没有显着改变结果。根据 IV 结果，我们没有发现心理治疗对自杀未遂、精神病再入院、辅助生活或劳动力市场依恋的影响的支持。但是，由于包括概率估计在内的置信区间，我们不能排除较小的影响。这项研究的主要贡献是关于广泛结果和大量代表性人群的新证据。