Does age impact on rating melancholic and non-melancholic depressive symptoms?

Melancholic depression has long evaded attempts at accurate definition. A range of factors may influence symptom reporting and so compromise definitional attempts. One possible factor is age, and its possible influence led to the current study examining the impact of age on the reporting of melancholic and non-melancholic depressive symptoms.

A set of 32 self-rated depression items from the SDS depression measure and weighted to both melancholic and non-melancholic depressions were analysed for any impact of age in clinically diagnosed melancholic and non-melancholic depressed patients.

Melancholic and non-melancholic patients did not differ by gender, severity of depression or duration of current episode. None of the melancholic items from the SDS showed a linear increase with age. Analyses of factor analytic derived constructs identified one factor as evidencing a linear decrease (rather than increase) in scores with age in the melancholic patients. Differential item functioning was only found for melancholic patients' scores on the 'non-melancholic scale', with a decrease across age. Simulated data revealed, for the same scale, a decrease in both melancholic and non-melancholic patients.

Our assessment strategies effectively excluded those with severe melancholia and who were unable to complete self-report measures, and may have contributed to study findings. As we had few patients over the age of 70, age effects in elderly patients may have missed identification.

We found no evidence for melancholic symptoms to increase in severity with age. To the contrary, some items decreased in severity with age in both melancholic and non-melancholic patients. Overall study results are reassuring in indicating that age is unlikely to distort analyses seeking to differentiate those with melancholic and non-melancholic depressive conditions.