Risk factors for complete, attempted suicide in schizophrenia 'confirmed'

By Sarah Pritchard, medwireNews Reporter

Among individuals with schizophrenia, those earliest in their illness course and those with a history of suicide attempts have the highest suicide-related mortality rates, reveals analysis of the international Ziprasidone Observational Study of Cardiac Outcomes (ZODIAC).

Despite there being low overall completed and attempted suicide rates during the 1-year follow up, at 0.19% and 0.59%, respectively, the findings confirm those of previous studies, remark the researchers in TheJournal of Clinical Psychiatry.

“A greater understanding and timely recognition of key risk factors for suicidal events would help focus clinical priorities and resources on highly vulnerable patients during critical time periods”, suggest W Wolfgang Fleischhacker (Medical University Innsbruck, Austria), and co-authors.

ZODIAC – an open-label, randomised trial – included 18,154 patients who were followed up in 18 countries between 2002 and 2007.

A total of 35 completed and 108 attempted suicides occurred during follow-up, with no significant differences between the age or gender of the individuals. However, the mean length of time since schizophrenia diagnosis was shorter among those who completed or attempted suicide, at 7 and 11 years, respectively, versus 13 years among those who did not attempt it.

Multivariate analysis of potential baseline risk factors for suicide showed that having a history of suicide attempts significantly increased the risk of completed and attempted suicide, with odds ratios (OR) of 2.6 and 5.0, respectively. Furthermore, being hospitalised more than five times in the past significantly increased the risk of a suicide attempt, with an OR of 2.1.

Use of hard suicide methods involving trauma were more frequent in completed suicides compared with attempted suicides (60 vs 33%), while soft methods such as drug overdose were more common among attempted suicides (65 vs 23%).

Finally, rates of completed suicide per 100 person–years of exposure were highest for individuals who were early in their schizophrenia illness course, with rates of 0.44 and 0.47 for those diagnosed up to a year and between 1 and 3 years prior to the study, respectively, versus rates of 0.24 and lower for those diagnosed in the more distant past.

“In summary, our results, obtained in a large, prospective randomized study in subjects with schizophrenia, confirm and expand the knowledge about completed or attempted suicide... as well as the risk factors associated”, conclude Fleischhacker et al.

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