Sleep disturbance and suicidal intent in recent attempters P. Ferentinos 1, C. Christodoulou 1, E. Porichi 1, D. Dikeos 2, C. Papageorgiou 1 1 Athens University Medical School, 2nd Department of Psychiatry, Attikon General Hospital, Athens, Greece 2 Athens University Medical School, 1st Department of Psychiatry, Eginition Hospital, Athens, Greece

INTRODUCTION Sleep disturbance and short self-reported sleep duration have been associated, in both cross-sectional and prospective studies, with suicidal ideation and behavior even after adjusting for the presence of major depression. Yet, it is unknown whether they also correlate with the severity/lethality of suicidal acts, which is highly predicted by suicidal intent. OBJECTIVES This cross-sectional study in a sample of consecutive hospitalised suicide attempters aimed to investigate (1)whether temporally proximal self-reported sleep disturbance was independently associated with suicidal intent, (2)whether sleep disturbance had a specific effect on suicidal intent in certain patient groups, (3)whether sleep disturbance partially mediates the association of various predictors with suicidal intent.

METHODS Measures: The presence of major depression during at least 2 weeks preceding the attempt was investigated with the 10-item Major Depression Inventory (MDI) whereby DSM-IV-TR diagnosis of current major depressive episode (current MDE) was derived. Temporally proximal sleep disturbance (i.e. reported during the two weeks preceding the attempt) was retrospectively assessed with the 8-item Athens Insomnia Scale (AIS); subjects were also asked to report the average night sleep duration (ANSD) during this period. Suicidal intent was recorded with the 15-item Beck’s Suicide Intent Scale (BSIS). Statistical analysis: BSIS score was sequentially regressed on AIS total score, specific AIS items, and ANSD after adjusting for gender, age, living alone, being unemployed, psychiatric diagnoses, previous suicide attempt, and current MDE. Structural equation models (using bootstrapping to calculate SEs) were built to investigate indirect effects.

RESULTS Descriptives: 130 subjects (60% females), aged (44.1±17.5) years were included. Assessments took place 4.8±5.7 days post-attempt. 66.2% lived alone while 37.1% were unemployed. Subjects had a diagnosis of affective disorder (35.4%), schizophrenia (10%), personality disorders (4.6%) or alcohol abuse (3.1%). Methods employed in most recent attempt included drug-overdose (81.5%), self-poisoning (6.2%) and self-injury (12.3%). 52.3% reported previous attempts. 38.5% of participants fulfilled DSM-IV-TR criteria of current MDE. During the two-week time period before the attempt, 62.3% reported suffering from insomnia (AIS score ≥6) while 41.5% slept less than 5 hours per night on average. 35.4% of attempters scored high on BSIS (>=14) while 46.2% had intermediate scores (5-13).

RESULTS Multiple regressions: After adjusting for covariates, BSIS was independently associated with AIS total score (p=0.039) (Fig.1), and ANSD≤5hr (p=0.021). Out of specific AIS items, items 3 (late insomnia) (p=0.012), 4 (inadequate sleep duration) (p=0.002) and 8 (hypersomnia) (p=0.044) were significantly associated with BSIS. Significant interactions of affective disorder diagnosis with AIS score (p=0.001) and ANSD (p=0.027) were recorded. Structural equation models: Indirect effects of affective disorder and alcohol abuse diagnoses, current MDE and age on BSIS via AIS score tested significant (p=0.027, 0.034, and 0.020, respectively)(Table 1).

CONCLUSIONS Suicidal intent was independently associated with insomnia and short self-reported sleep duration (less than 5 hours per night on average) during a two-week time period preceding the suicide attempt. These effects were significantly stronger in patients with affective disorders. Insomnia partially mediated the effect of affective disorder and alcohol abuse diagnoses, current major depression and age on suicidal intent.

Fig.1. Structural equation model * * ** * * *** *p<0.05 ** p<0.01 ***P< Standardised coefficients are displayed

Table 1. Direct (D), Indirect (I)(via AIS score) and Total effects Direct effectIndirect effectI/DTotal effect St.est.p-value*St.est.p-value*St.est.p-value* Alcohol dx →BSIS Affective dx →BSIS Age →BSIS Current MDE →BSIS Standardised estimates (st.est.) of effects are displayed. * SEs and p-values calculated with bootstrapping (1000 samples)