Background: Mental illness among adolescents and young adults is a significant public health concern globally, particularly in low and middle income countries like Nigeria, where mental health infrastructure is limited. Young Nigerians face pervasive stigma, inadequate mental health literacy, and limited access to care, often influenced by spiritual and sociocultural factors. This study explores the lived experiences of adolescents and young adults with mental illness, focusing on how they navigate stigma, emotional distress, and systemic barriers while leveraging coping mechanisms.

Methods: Using an interpretive phenomenological analysis (IPA) approach, this longitudinal qualitative study examined the experiences of 16 participants aged 15-35 years diagnosed with mental illness. Participants were purposively sampled from a psychiatric hospital in South-Eastern Nigeria. Data were collected through semi-structured, in-depth interviews over nine months. Thematic analysis was employed to identify patterns and interpret the dynamic interplay between societal stigma, individual coping strategies, and systemic challenges.

Results: Five key themes emerged: (1) Perceptions of mental illness as abnormality and shame; (2) Emotional and social struggles, including loneliness, strained family relationships, and fear of the future; (3) Coping mechanisms such as reliance on family, spirituality, and professional care; (4) Stigma and discrimination, highlighting both internalised stigma and advocacy efforts; and (5) Barriers to care, including accessibility issues and the need for youth-specific services. Participants reported evolving perceptions and coping strategies over time, facilitated by therapy, social support, and community awareness initiatives.

Conclusions: This study emphasises the complex interplay between stigma, resilience, and systemic barriers in the mental health journeys of young Nigerians. Findings highlight the need for culturally sensitive interventions, family-focused psychoeducation, youth-specific services, and community-integrated approaches to reduce stigma and enhance care. These insights provide actionable recommendations for improving mental health systems in resource-limited settings.