Summary: Certain personality traits strongly affect the likelihood of developing insomnia. High neuroticism—a trait linked to emotional instability—was far more common among people with insomnia, while greater openness to experience appeared to protect against sleep problems. Anxiety was identified as the main mechanism that explains how neuroticism leads to insomnia; depression did not play a significant mediating role.
A study from the Faculty of Medicine at the University of São Paulo (USP) examined how the five major personality traits relate to insomnia and how anxiety and depression influence that relationship. The findings point to distinct risk and protective factors rooted in personality, with implications for assessment and treatment.
Key Facts:
- Neuroticism Risk: 61.7% of diagnosed insomniacs had high neuroticism versus 32% of the non-insomnia group.
- Protective Trait: Higher openness to experience was associated with lower insomnia severity.
- Anxiety Link: Anxiety fully mediated the effect of neuroticism on insomnia.
Source: FAPESP
Background and purpose
Insomnia is one of the most common sleep disorders in adults, characterized by difficulty falling asleep, staying asleep, or returning to sleep after nocturnal awakenings. Worldwide estimates suggest that around 30% of people experience insomnia symptoms, and local studies indicate even higher prevalence in some regions. Because insomnia increases the risk of hypertension, diabetes, anxiety and depression and impairs overall quality of life, researchers at USP investigated whether personality traits predispose individuals to onset and maintenance of insomnia.
Bárbara Araújo Conway, a sleep psychologist and author of the master’s dissertation defended at the Institute of Psychiatry of FM-USP, led the study with support from FAPESP and supervision from Professor Renatha El Rafihi-Ferreira. The team aimed to identify which personality traits are most strongly linked to insomnia and whether anxiety or depression explains those links.
Five personality traits
The study relies on the Big Five model of personality: extroversion, neuroticism, agreeableness, openness to experience, and conscientiousness. Briefly:
Extroversion: Higher extroversion typically means sociability, assertiveness and ease with group interactions; lower extroversion indicates a preference for solitude or quiet settings.
Neuroticism: Measures emotional instability and tendency toward negative emotions; high neuroticism correlates with greater sensitivity to stress and a higher risk of anxiety and depression.
Agreeableness: Reflects empathy, cooperativeness and concern for others; low agreeableness is linked with skepticism or distrust.
Openness to experience: Characterizes curiosity, creativity and willingness to try new things; lower openness favors routine and conventionality.
Conscientiousness: Relates to discipline, persistence and goal-directed behavior; very high levels can lead to perfectionism, while low levels reflect less structure or motivation.
The study
The researchers evaluated 595 adults aged 18 to 59 split into two groups: people with a formal diagnosis of insomnia who had sought clinical care, and a control group without insomnia complaints. Participants completed a validated 60-item personality inventory (NEO Five-Factor Inventory), the Insomnia Severity Index, the Hospital Anxiety and Depression Scale, DSM-5 symptom questions and a sociodemographic questionnaire. Statistical analyses included descriptive statistics, correlations, stepwise linear regression, and mediation and moderation models to examine mechanisms linking personality and insomnia severity.
Results showed that insomnia patients scored significantly higher on neuroticism and lower on agreeableness, openness, and conscientiousness compared with controls. Extroversion did not differ meaningfully between groups. Specifically: 61.7% of insomniacs had high neuroticism versus 32% of controls; 40.7% of insomniacs had low openness versus 23% of controls; 31.5% of insomniacs had low agreeableness compared with 23.2% of the control group; and 37.7% of insomniacs had low conscientiousness versus 24.1% of controls.
Further modeling showed a direct negative association between openness to experience and insomnia severity, and an indirect positive association between neuroticism and insomnia severity. Anxiety emerged as the mediating factor that explained how neuroticism leads to worse insomnia, while depression did not significantly mediate that relationship.
Clinical implications
Because personality traits influence vulnerability to insomnia and related health outcomes, understanding patients’ personality profiles can improve assessment, prevention and individualized treatment planning. The study emphasizes that evaluating and addressing anxiety is crucial when treating insomnia, especially for patients with high neuroticism. Treatments that focus solely on sleep without targeting underlying anxiety may be less effective for this subgroup.
The current gold-standard therapy for chronic insomnia is cognitive-behavioral therapy for insomnia (CBT-I). However, access to CBT-I specialists is limited in many settings. The authors recommend broader assessment of psychological factors and development of transdiagnostic treatment protocols that combine behavioral techniques with interventions addressing shared emotional processes like anxiety.
Tailoring interventions to a patient’s personality and emotional profile—integrating sleep-focused strategies with anxiety treatment when needed—may improve outcomes and contribute to more personalized, effective non-pharmacological care for insomnia.
About this insomnia and personality traits research news
Author: Heloisa Reinert
Source: FAPESP
Contact: Heloisa Reinert – FAPESP
Image: Image credited to Neuroscience News
Original Research: Open access. “Personality traits and insomnia: direct and anxiety-mediated associations” by Bárbara Araújo Conway et al.
Abstract
Personality traits and insomnia: direct and anxiety-mediated associations
Insomnia is among the most prevalent sleep disorders in adults. Past studies suggest personality traits—especially neuroticism—may predispose individuals to insomnia and help perpetuate it, but mechanisms remain unclear. In this sample of 595 participants, researchers used validated measures of insomnia severity, the NEO Five-Factor Inventory, and standardized anxiety and depression scales to explore these relationships.
Analyses revealed a direct negative association between openness to experience and insomnia severity and an indirect positive association between neuroticism and insomnia severity. Anxiety was identified as a mediator of the neuroticism–insomnia relationship; depression did not function as a key mediator in this model. These results indicate that neuroticism and openness are significant predictors of insomnia severity, with openness potentially acting as a protective factor. Longitudinal studies are needed to confirm causality, and findings may support development of more personalized psychological and behavioral protocols for treating insomnia.