Disordered personality style: higher rates in non-melancholic compared to melancholic depression

We test whether there is differential representation of disordered personality function across melancholic and non-melancholic depressive sub-types, with levels of differentiation examined against differing sub-typing measures.

In a sample of 245 subjects meeting criteria for a non-psychotic major depressive episode lasting less than 2 years, we examine for differential rates of disordered personality style across melancholic and non-melancholic depression, using four differing sub-typing measures (i.e., DSM-III-R and DSM-IV criteria, Newcastle Index, and the CORE measure). Disordered personality was assessed by psychiatrist ratings of 15 differing personality styles underpinning disorder classes, and several parameters and domains that reflect the arenas whereby disordered personality may be manifested.

However defined, those with non-melancholic depression were distinctly more likely to rate as showing disordered personality function, with over-representation to an avoidant personality disorder style being the most consistently and strongly identified personality disorder class. Because of limitations to several of the sub-typing measures, we focus on the DSM-IV system. Discriminant function analyses indicated that those so identified as having non-melancholic depression were significantly more likely to rate as having avoidant and schizoid personality styles. A principal components analysis of our 15 differing personality disorder classes identified three molar classes corresponding to the three-cluster DSM system. Again, non-melancholic (compared to melancholic) subjects were more likely to return higher scores: in order, an 'anxious and fearful' (Cluster C) personality style, then an 'eccentric' Cluster A, and somewhat less clearly, a 'dramatic' Cluster B personality disorder style. Specificity to the non-melancholic depressive class was again suggested in relation to a large number of the parameters and domains measuring disordered personality function.

Disordered personality function appears distinctly more likely in non-melancholic, compared to melancholic depression.