Type D Personality and Life Satisfaction in Bipolar Disorder Type 2 and Major Depressive Disorder

Bipolar Disorder Type II (BD-II) and Major Depressive Disorder (MDD) are chronic mood disorders that contribute substantially to global disability, psychosocial impairment, and reduced quality of life. BD-II is characterized by recurrent major depressive episodes and at least one hypomanic episode, whereas MDD is characterized by recurrent depressive episodes without a history of mania or hypomania. Although both disorders share several clinical features, they differ in course, prognosis, treatment approaches, and familial aggregation patterns. Family and twin studies have consistently demonstrated that genetic and familial factors contribute significantly to the development of mood disorders. Consequently, first-degree relatives of individuals with mood disorders may exhibit subclinical affective traits, maladaptive personality characteristics, and psychosocial difficulties even in the absence of a diagnosable psychiatric disorder.

Type D ("distressed") personality is a stable personality construct characterized by the coexistence of two major traits: negative affectivity and social inhibition. Individuals with Type D personality tend to experience persistent negative emotions while simultaneously suppressing emotional expression in social interactions. Previous studies have shown that Type D personality is associated with increased psychological distress, anxiety, depressive symptoms, poorer coping abilities, lower quality of life, and adverse health outcomes. Similarly, life satisfaction is an important indicator of subjective well-being and psychological adjustment, and it may be influenced by both personality characteristics and familial vulnerability factors.

Although Type D personality has been investigated in patients with various psychiatric disorders, including mood disorders, little is known about the prevalence and clinical significance of Type D personality traits among parents of individuals diagnosed with BD-II or MDD. Furthermore, no study has directly compared Type D personality characteristics, psychiatric symptom severity, and life satisfaction among parents of patients with these two mood disorders. Understanding these familial psychological characteristics may provide important insights into the broader psychosocial and hereditary dimensions of mood disorders.

The present study was designed as a cross-sectional observational study conducted at the Psychiatry Outpatient Clinic of Elazığ Fethi Sekin City Hospital, Turkey. All participants included in the study were/will be recruited by MD Dilek ÖRÜM (Associate Professor of Psychiatry, dr.dilekulukan@gmail.com). The study recruited/will recruit 30 patients with BD-II; 30 patients with MDD; 30 healthy control subjects; mothers and/or fathers of 30 healthy control subjects, mothers and/or fathers of 30 patients with BD-II, and mothers and/or fathers of 30 patients with MDD who are in remission and receiving follow-up care at the Psychiatry Outpatient Clinic of Elazığ Fethi Sekin City Hospital, Turkey. The psychiatric diagnoses were made according to Text Revision of Fifth Edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) criteria. To minimize the influence of acute illness-related factors, only parents of patients who are currently in remission will be included. Parents with active psychiatric disorders, a history of major psychiatric illness, significant neurological disorders affecting cognition, or severe medical illnesses will be excluded.

All participants completed/will complete a sociodemographic data form and a battery of validated psychometric instruments. Type D personality characteristics will be assessed using the Type D Personality Scale (DS14), which evaluates negative affectivity and social inhibition. General psychiatric symptom severity will be evaluated using the Brief Psychiatric Rating Scale (BPRS). Subjective well-being and life satisfaction will be assessed using the Adult Life Satisfaction Scale (ALSS). Sociodemographic variables including age, sex, marital status, and educational level will also be collected.

The primary objective of the study was/is to compare Type D personality traits and life satisfaction levels between patients with BD-II-MDD and parents of patients with BD-II and parents of patients with MDD. Secondary objectives include/d examining the relationships between Type D personality dimensions, psychiatric symptom severity, and life satisfaction within each group and across the entire sample. The study additionally aims to identify demographic and clinical factors associated with life satisfaction among parents of individuals with mood disorders.

The study hypothesizes/d that parents of patients with BD-II will demonstrate higher levels of Type D personality traits and lower levels of life satisfaction than parents of patients with MDD. It was/is also hypothesized that greater Type D personality characteristics was associated/will be associated with increased psychiatric symptoms and lower life satisfaction.

Statistical analyses will be performed using SPSS 26.version software. Descriptive statistics will summarize demographic and clinical characteristics. Group comparisons will be conducted using chi-square or Fisher's exact tests for categorical variables and independent-samples t-tests or Mann-Whitney U tests for continuous variables, depending on data distribution. Correlation and regression analyses will be performed to investigate associations between Type D personality traits, psychiatric symptoms, and life satisfaction. Statistical significance will be set at p < 0.05.

The findings of this study may contribute to a better understanding of the familial psychological characteristics associated with mood disorders and may help identify potential targets for preventive, supportive, and psychosocial interventions among family members of affected individuals. By exploring the relationship between Type D personality and life satisfaction in parents of patients with BD-II and MDD, this study seeks to expand current knowledge regarding familial vulnerability factors and psychosocial outcomes related to mood disorders.