Difference in prevalence of common mental disorder as measured using four questionnaire delivery methods among young...

Previous studies have suggested that interviewer-administered questionnaires can under-estimate the prevalence of depression and suicidal ideation when compared with self-administered ones. We report here on differences in prevalence of reporting mental health between four questionnaire delivery modes (QDM).

Mental health was assessed using the Shona Symptom Questionnaire (SSQ), a locally validated 14-item indigenous measure for common mental affective disorders. A representative sample of 1495 rural Zimbabwean adolescents (median age 18) was randomly allocated to one of four questionnaire delivery modes: self-administered questionnaire (SAQ), SAQ with audio (AASI), interviewer-administered questionnaire (IAQ), and audio computer-assisted survey instrument (ACASI).

Prevalence of common affective disorders varied between QDM (52.3%, 48.6%, 41.5%, and 63.6% for SAQ, AASI, IAQ, and ACASI respectively (P<0.001)). Fewer participants failed to complete SSQ using IAQ and ACASI than other methods (1.6% vs. 12.3%; P<0.001). Qualitative data suggested that respondents found it difficult answering questions honestly in front of an interviewer.

Direction of accuracy cannot be ascertained due to lack of objective or clinical assessments of affective disorders.

Estimates of prevalence of psychosomatic symptoms and suicidal ideation varied according to mode of interview. As each mode's direction of accuracy remains unresolved evaluations of interventions continue to be hampered.