Dysfunctional parenting: over-representation in non-melancholic depression and capacity of such specificity to refine sub-typing depression measures

We examine the proposition that dysfunctional parenting is more likely to be experienced by those with non-melancholic (compared to melancholic) depression and that, as a consequence, such specificity allows the validity of varying definitions of melancholia to be examined and their utility sharpened. We study a sample of 245 non-psychotic patients meeting DSM-III-R criteria for a major depressive episode and assign them to melancholic and non-melancholic sub-sets according to five separate sub-typing measures (DSM-III-R; DSM-IV; Newcastle; 'Clinical' and CORE criteria). We assess dysfunctional parenting by use of the Parental Bonding Instrument (PBI), and by structured psychiatrist assessment and self-report ratings of a range of dysfunctional parental experiences, with independent assessment and self-report ratings of a range of dysfunctional parental experiences, with independent assessment of the last by reports from corroborative witnesses and from the patients' referring therapists. The five sub-typing measures assigned varying percentages of the sample (24-42%) to a 'melancholic' sub-type. When Newcastle Index assignments were examined, there was no evidence that dysfunctional parenting had any specificity to non-melancholic depression. Neither the DSM-III-R nor DSM-IV systems demonstrated specificity in relation to PBI scores, but several interview-assessed dysfunctional parenting characteristics were over-represented in their non-melancholic sub-sets. 'Clinical' definition showed the greatest over-representation of dysfunctional parenting to those assigned as having non-melancholic depression. The CORE measure, a behaviourally weighted measure of psychomotor disturbance, was the next most differentiating. Importantly, those assigned as having non-melancholic depression by all five measures were more likely to be rated by corroborative witnesses as being exposed to anomalous parenting, validating the subjects' self-reports, arguing against results being an artefact of clinician-based assessment, and supporting the specificity of dysfunctional parenting to a depressive sub-type.