عوامل خطر اولیه برای خودکشی در یک گروه روان پریشی اپیدمیولوژیک اپیزود اول

Background Much remains unknown about whether there are early risk factors for suicide in psychosis. Aim The aim of the study was to determine whether there are any identifiable early symptom clusters, aetiological factors or illness course markers for suicide in first episode psychosis. Method A total of 2132 patients with first episode psychosis presenting to secondary care services in London (1965–2004; n = 1474), Nottingham (1997–1999; n = 195) and Dumfries and Galloway (1979–1998; n = 463) were traced after up to 40 years (mean 13 years) following first presentation. Risk factors were identified from the Operational Checklist for Psychotic Disorders rated for the first year following presentation. Results Overall, there were 51 suicides and 373 deaths from other causes. Male gender (RR 2.84, 95% CI 1.20–6.69, p = 0.02) and a cumulative threshold effect of symptoms early in the illness (RR 6.81, 95% CI 2.33–19.85, p < 0.001) were associated with a higher propensity for later completed suicide. There was also a suggestion that early manic symptoms might increase the risk of later suicide irrespective of initial diagnosis. Conclusion Suicide risk was associated with a cumulative threshold effect of symptoms and manic symptoms. As suicide is a relatively rare event in psychotic disorders, general population-based prevention strategies may have more impact in this vulnerable group as well as the wider population.

Suicide is one of the main causes of excess death in psychotic disorders (Ösby et al., 2000 and Ösby et al., 2001). Saha et al. (2007) estimate the risk in schizophrenia to be 13 times greater than in the general population. Reducing the risk of suicide amongst patients with psychosis is an international public health priority and considerable work has been done to identify specific risk factors (Hawton et al., 2005a, Hawton et al., 2005b and Pompili et al., 2007). Most risk factor studies to date have made a clear distinction between studying either schizophrenia and related non-affective psychosis or affective disorders. However, recent evidence, particularly from genetic studies, suggests that these are far from distinct disease entities (Cardno et al., 2002 and Owen et al., 2007) and clinical diagnosis is known to vary over time (Amin et al., 1999 and Veen et al., 2004). The nature of the study design of previous research must also be taken into account when interpreting the findings. For example in a case–control study, if the controls are population-based, living patients, with the same psychotic illness as the completed suicide cases, the study will assess risk factors for suicide in the population of psychotic patients (Pompili et al., 2009 and Reutfors et al., 2009) and this will include risk factors for suicide incidental to the diagnosis of a psychotic illness. Whereas if controls are suicides by people with other disorders (McGirr and Turecki, 2008), this investigates a very different question about which factors are specific to suicide in psychotic illness. A study design which provides strong evidence is a long-term cohort study, such as that conducted by Limosin et al. (2007) for schizophrenia in 3434 French patients. This study had the additional advantage that factors relating to clinical risk, such as smoking status, alcohol problems, illicit drug use and previous suicide attempt were recorded. However, a drawback in the design was that it was based on a prevalence population recruited from all patients attending either as inpatients or outpatients during a specified period rather than an incident cohort. In the UK, Osborn et al. (2008) carried out a general practice research database study of demographic and family practice health service predictors in a large cohort of patients with schizophrenia (n = 18,555; 48 suicides), bipolar disorder (n = 10,742; 41 suicides) and other severe mental illness (n = 16,839, 54 suicides). They chose variables such as consultation rate, use of antidepressant medication and social deprivation quintiles, which are known to be valid and reliable in this working clinical database. Yet once more, this cohort was based on all patients with the appropriate diagnoses rather than incident cases, so the conclusions of higher risk being associated with increased consultation rates, antidepressant prescribing and living in less deprived areas have to be interpreted knowing that they apply to patients at diverse stages of their illness rather than a complete cohort from initial onset. Previous studies have often sought to identify risk factors relating to the period leading up to suicide, e.g. noncompliance with medication in the month prior to death, inpatient or outpatient status, or loss of contact with mental health services (Hunt et al., 2006). There has been very little research into whether factors identifiable early in the illness course are markers for later suicide, although De Hert et al. (2001) found that early onset of a defect state in young people with schizophrenia (under the age of 30 years) was protective from suicide. We have used an inception cohort design to investigate potential early risk factors for suicide in a large cohort of first onset psychosis patients with a long follow-up period (mean more than 13 years).