Two depression rating instruments in Nigerian patients.

Having been developed in a foreign culture, the extent to which items on the Hamilton Depression Rating Scale (HDRS) and the Zung Self-Rating Scale (ZS) reflect the features of depression as obtained in clinical interviews in Nigeria is uncertain. Also, items predictive capabilities for the severity of depression and the extent of concurrence between the two scales in assessing depression need to be ascertained. Seventy- eight patients who met the ICD 10 criteria for major depressive disorder completed the ZS and had the HDRS completed on them. These patients, (in addition to six others) had their case records examined and their symptoms of depression extracted. The predictive values of each item on the scales to the overall severity of depression, the intra-scale and inter-scale items correlations were calculated. Sleeplessness, somatic symptoms and sad mood were the commonest symptoms reported by patients with major depressive disorder. The Zung Scale showed that joylessness, lack of clarity of the mind, and difficulty taking decisions were also very common. The HDRS had better access to somatic symptoms than the Zung Scale, although items on the Zung Scale generally had better predictive value of the overall severity of depression than items on the HDRS. The HDRS had a moderate inter-scale correlation (r=0.43) relative to the Zung Scale, but only three equivalent items (depressed mood, suicide and impaired appetite) on the two scales had moderate and significant correlations. The HDRS and the ZS are very useful rating scales in depression but some modifications and additions will make them more applicable.