Co-morbid PTSD and suicidality in individuals with schizophrenia and substance and alcohol abuse.

BACKGROUND: Suicide risk is high in schizophrenic patients and is further elevated in dual diagnosis patients. Suicide behaviour is a continuum from ideation, plans to attempts. Exposure to traumatic stress and co-morbid PTSD is elevated in schizophrenic patients. Suicide behaviour is also common in non-psychotic PTSD patients. This study aimed to investigate the effect of trauma and co-morbid PTSD on suicide behaviour in dual diagnosis patients and whether co-morbid PTSD would further elevate suicide risk.

METHOD: This was a cross-sectional study in which suicide behaviour was compared in those with and without co-morbid PTSD in 110 patients suffering schizophrenia and alcohol and/or substance abuse.

RESULTS: 100 (91%) reported at least one traumatic event with an average of 4.3 events. 31 (28%) patients met criteria for full PTSD. Current suicidal ideation was reported by 39 (35%) and 23 (21%) reported plans and ideation, 69 (63%) reported at least one previous suicide attempt. Suicide behaviour was significantly associated with an increasing number of traumatic events. Suicidality was significantly associated and elevated with co-morbid PTSD. Analysis indicated that the effect of trauma on suicide behaviour appeared to be mediated by hopelessness.

CONCLUSIONS: Suicide behaviour was not associated with exposure to trauma per se but was associated with incremental exposure to traumatic experiences. Consistent with the study hypotheses, co-morbid PTSD further adds to the risk of suicide behaviour in an already vulnerable group.