Open access. Bipolar and other psychiatric disorders are associated with considerably increased risk of suicidal behaviour, which may include self-poisoning with medication used to treat the disorder. Therefore, choice of medication for treatment should include consideration of toxicity, especially for patients at risk. The aim of this study was to estimate the relative toxicity of specific drugs within two drug categories, antipsychotics and mood stabilizers, using large-scale databases to provide evidence that could assist clinicians in making decisions about prescribing, especially for patients at risk of suicidal behaviour.