Trajectories of Depression Among Individuals with Acquired Physical Disabilities and Influencing Factors In South Korea: A Growth Mixture Modeling Approach

Background and Purpose:

Population aging and medical advancements have extended life expectancy but also increased disability prevalence. While premature mortality has declined, Years Lived with Disability (YLD) for those with acquired impairments has risen. In South Korea, a rapidly super-aging society, acquired disabilities from chronic diseases and accidents have become a significant social burden.

The decline in physical health profoundly affects mental well-being, making individuals with physical disabilities particularly vulnerable to depression. Those with acquired physical disabilities are particularly vulnerable; they face sudden functional loss, shifts in social roles, and economic hardships. According to stage models of disability adjustment, individuals inevitably experience depression as they transition from denial and anger toward acceptance.

Depression is a dynamic process shaped by the interaction of environmental and individual factors over the life course, rather than a static state. To fully understand depression in individuals with acquired physical disabilities, research must move beyond cross-sectional observations to focus on long-term trajectories. Identifying developmental pathways and their associated risk or protective factors through longitudinal studies is essential for designing targeted interventions tailored to groups experiencing either worsening or alleviating symptoms.

Methods:

Growth Mixture Modeling (GMM) was used to identify latent trajectory groups of depression. Data were drawn from Waves 1-6 (2018-2023) of the Disability and Life Dynamics Panel Survey conducted by the Korea Disabled People's Development Institute. The sample included 3,004 adults with acquired physical disabilities, encompassing both external physical disabilities (physical, brain lesion, visual, hearing, speech, and facial disabilities) and internal organ disabilities (kidney, heart, liver, respiratory, ostomy, and epilepsy).

Influencing factors are categorized into sociodemographic factors (gender, age, education level, marital status, employment, economic hardship), disability and health factors (type and severity of disability, age at onset, duration since onset, multiple disabilities, subjective health, need for activities of daily living [ADL] assistance), individual factors (disability acceptance, self-esteem), and social factors (social support, perceived respect).

Results:

The depressive trajectories of individuals with acquired physical disabilities were classified into three latent classes: Low-level Alleviating (52.2%), Mid-level Alleviating (40.4%), and High-level Deteriorating (7.4%). Notably, the gap between the ‘High-level Deteriorating’ and ‘Low-level Alleviating’ groups widened from 10 to 18 points over six years, confirming that inequality in depressive levels significantly intensified.

Across all groups, disability acceptance and subjective health status emerged as the primary determinants of trajectory membership. Specifically, individual psychological factors and health status were significant in distinguishing the 'High-level Deteriorating' group from the others. Conversely, socioeconomic resources and backgrounds, such as employment and education, played a crucial role in differentiating the 'Mid-level Alleviating' and 'Low-level Alleviating' groups.

Conclusions and Implications:

Tailored intervention strategies are needed for each depressive trajectory group. For the high-risk 'High-level Deteriorating' group, immediate clinical screening and intensive psychological services are required to address health issues and emotional stressors. For the ''Low-level and Mid-level Alleviating' groups, focus should be placed on strengthening socioeconomic empowerment—such as vocational support and educational services—to prevent the recurrence of depressive symptoms and ensure long-term emotional stability.