Does a history of suicide attempt predict higher antipsychotic dosage in schizophrenia?

Antipsychotic dosage is generally adjusted by physicians depending on the stability of the patient and the response to that particular drug. Our hypothesis is that patients with previous suicide attempt are prescribed higher doses of antipsychotics.

We examined the dosage and patterns of antipsychotic use in regard to past suicidal behaviour.

For this study, 304 subjects with schizophrenia spectrum disorders between the ages of 18 and 75 were recruited. A cross-sectional assessment was used for this study, in which data were collected from each patient through an interview and self-report questionnaires. The percentages of the Compendium of Pharmaceuticals and Specialties (CPS) maximum recommended daily dose were applied to standardize antipsychotic dosages across different treatments. We compared the standardized dosage of antipsychotics in schizophrenics with previous suicide attempts and those who have never attempted suicide.

Applying the ANCOVA, our preliminary results show no significant difference (P = 0.467) in antipsychotic dosage in the attempters and non-attempters. The prescribed clozapine dosage fails to show a significant relationship with suicidal history (P >0.05).

In summary, our analysis does not show antipsychotic dosage adjustment based on past suicide attempt, after controlling for the current suicidal ideation and hopelessness.