The Effects of Suicide Motivation Inhibition Model on Suicidal Ideation in Patients with Major Depressive Disorder

Abstract

Introduction Major depressive disorder (MDD) is one of the most significant global challenges in mental health. It is characterized by persistent emotional distress that may escalate suicidal behavior. Although patients with MDD often receive antidepressant medication, suicidal ideation may persist and, in some cases, result in suicide, particularly during the critical period immediately following hospital discharge. The suicide motivation inhibition model for patients with MDD emphasizes modifying automatic thoughts and problem-solving perspectives, especially those shaped by feelings of defeat and entrapment by their circumstances. This therapeutic approach represents a promising strategy to mitigate suicidal ideation and reduce the risk of suicide. 

Objectives To compare suicidal ideation scores between patients with MDD who received standard care incorporating care through the suicide motivation inhibition model, and those who received standard care alone, assessed at baseline, immediately after intervention, two weeks after discharge, and four weeks after discharge. 

Design This study employed a two-group experimental design with repeated measures. It applied the Integrated Motivational Volitional (IMV) model of suicidal behavior, combined with principles of cognitive behavioral therapy (CBT) and problem-solving therapy (PST), to develop an intervention framework aimed at inhibiting suicidal motivation among patients with MDD. The intervention was delivered individually over a two-week period, consisting of three sessions per week. Each session incorporated six structured activities: 1) understanding the illness, 2) exploring feelings of defeat and entrapment, 3) identifying automatic thoughts, 4) developing new perspectives, 5) learning problem-solving strategies, and 6) choosing new solutions to address problems.

Methodology The participants comprised patients diagnosed with MDD who met the following inclusion criteria: 1) admission to inpatient psychiatric care within 72 hours, 2) aged between 18 and 60 years, 3) a history of suicide attempt within the past month, 4) a suicidal ideation score of 19 or higher on the Thai version of the Suicidal Ideation Questionnaire, and 5) the ability to listen, speak, read, and write in Thai. A total of 40 participants were recruited through simple random sampling and subsequently assigned to either the experimental group (n = 20) or the control group (n = 20). The experimental group received the suicide motivation inhibition model in conjunction with standard care for a duration of two weeks, while the control group received standard care based on the level of suicide risk. Research instruments included the Suicide Motivation Inhibition Model, which demonstrated a content validity index of .89, and the Thai version of the Suicidal Ideation Questionnaire, which showed a reliability coefficient of .81. Suicidal ideation scores were assessed at four time points: baseline, immediately after intervention, two weeks after discharge, and four weeks after discharge. Data were collected between January and June 2025. Descriptive statistics were used to analyze demographic characteristics, while suicidal ideation scores were compared within and between groups using repeated measures two-way analysis of variance (ANOVA). Pairwise comparisons were further examined using Bonferroni post hoc tests.

Results In the experimental group, the majority of participants were female (60%), with a mean age of 25.05 years (SD = 5.34), and most were single (80%). The predominant method of suicide attempt was drug overdose (55%). The average duration of illness was 2.7 years (SD = 1.55), with a mean of 1.70 prior hospitalizations (SD = 0.73). In the control group, the majority were also female (55%), with a mean age of 26.75 years (SD = 4.68), and most were single (90%). The most common method of suicide attempt was drug overdose (30%). The average duration of illness was 2.85 years (SD = 1.49), with a mean of 1.45 prior hospitalizations (SD = 0.68). Comparative analysis of baseline demographic and clinical characteristics revealed no statistically significant differences between the two groups. Repeated measures two-way ANOVA demonstrated that suicidal ideation scores in the experimental group differed significantly across the four assessment points: baseline, immediately after intervention, two weeks after discharge, and four weeks after discharge (F = 398.160, p < .001). A significant interaction effect was observed between time and the intervention model (F = 12.115, p < .001). Between-group analysis further indicate d that suicid al ideation scores differed significantly between the experimental and control groups (F = 24.945, p < .001). Pairwise comparisons revealed that suicidal ideation scores at baseline were significantly higher than those immediately after intervention (MD = 18.50, p < .001), two weeks after discharge (MD = 17.175, p < .001), and four weeks after discharge (MD = 14.450, p < .001). Additionally, scores immediately after intervention differed significantly from those at two weeks after discharge (MD = -1.325, p < .001) and four weeks after discharge (MD = -4.050, p < .001). Finally, suicidal ideation scores at two weeks after discharge were significantly different from those at four weeks after discharge (MD = -2.725, p < .001).

Recommendation The suicide motivation inhibition model demonstrated effectiveness in preventing suicidal ideation during the 2–4 week period following hospital discharge. Psychiatric nurses can apply this intervention in the treatment of inpatients with MDD in psychiatric hospitals to enhance patient safety and reduce the risk of suicide.