Effectiveness of cognitive behavioral therapy for hypertension-related psychological distress: a two-phase randomized controlled trial in a Nigerian tertiary hospital

Background Hypertension is a major contributor to cardiovascular morbidity globally and is frequently accompanied by psychological distress, including anxiety and depression. Evidence on the efficacy of psychological interventions, particularly Cognitive Behavioral Therapy (CBT), for hypertension-related distress remains limited in the Sahara South of Africa. Objective This study examined the effectiveness of an 8-week CBT program in reducing psychological distress among adults with hypertension attending a Nigerian tertiary hospital, compared with a waitlist/usual care control group. Methods A two-phase randomized controlled trial was conducted. In Phase I, 242 hypertensive patients were screened for psychological distress. Phase II involved 42 participants with moderate to severe distress (mean age = 44.9 years) who were randomly assigned to either an 8-week CBT intervention or a waitlist control, continuing usual hypertension care. Psychological distress was assessed using the Symptom Checklist-13 (SCL-13). Data were analyzed per protocol using paired and independent t -tests and ANCOVA, controlling for baseline distress and age. Results The CBT group showed significant reductions in distress from baseline (M = 13.78, SD = 3.04) to post-test (M = 9.45, SD = 2.31), t (20) = 8.12, p < 0.001, whereas the control group showed no meaningful change (baseline M = 13.42, SD = 2.92; post-test M = 13.21, SD = 2.85), t (20) = 0.48, p = 0.630. Between-group comparisons confirmed greater improvement in the CBT group, t (40) = 5.64, p < 0.001, Hedges' g = −1.42. Subgroup analyses revealed large effects for participants with severe [ t (9) = 5.85, p < 0.001, partial η 2 = 0.62] and moderate distress [ t (10) = 4.42, p = 0.012, partial η 2 = 0.48]. Age significantly influenced outcomes, F (1, 40) = 5.24, p = 0.040, while gender and marital status did not. Conclusion These findings provide evidence that an 8-week CBT intervention significantly reduces psychological distress in individuals with hypertension. The results support the integration of CBT into hypertension care within Nigerian tertiary hospitals, highlighting the potential for broader implementation in similar clinical settings. Future research, involving larger and longer-term studies, is recommended to confirm the durability and generalizability of these findings.