Objectives. Metacognitive deficits are thought to be closely related to functional

impairment in a variety of mental health disorders. Understanding metacognitive differences

between groups may provide insight into etiology and treatment of mental illness. This study

sought to investigate group differences in metacognition and metacognitive changes over time in

response to long-term psychodynamic psychotherapy amidst a population with severe mental

illness diagnoses, specifically borderline personality disorder (BPD), narcissistic personality

disorder (NPD), and schizoid personality disorder (SPD).

Methods. Twenty-eight participants meeting inclusion criteria were selected from

amongst participants in the Austen Riggs Center’s (ARC) 11-year Follow-Along Study (FAS).

For each participant, two archived transcripts of Dynamic Interviews administered at least six

months apart were rated using the abbreviated Metacognitive Assessment Scale (MAS-a), which

provides scores for metacognitive functioning across four separate but interdependent domains of functioning. Raters had experience and training on the MAS-a and were blinded to personality

disorder group assignment of the FAS participants. Group differences and change over time were

assessed using a general linear model regression with metacognitive scores for occasion one as a

covariate and scores for occasion two as the dependent variable.

Results. Metacognitive scores improved over time in response to treatment for the

sample as a whole. Treatment effect sizes were medium to large. However, group differences

were negligible. Effect sizes for individual groups indicate possible differences in the way that

groups change over time. NPD group exhibited no change in Awareness of Others, but had a

large effect size in the category of Mastery. Large effect sizes in the category of Self-Reflectivity

were found for SPD and BPD groups. BPD demonstrated lower Mastery scores than NPD or

SPD.

Conclusions. Evidence for metacognitive improvement over time for the sample as a

whole suggests treatment at ARC is effective. Differences in effect sizes in change over time

between groups may suggest that personality disorder diagnosis influences treatment outcomes, a

hypothesis that may be more readily testable with a larger sample. Generalizability of results is

limited by the relatively small size of sample subgroups and by the unique patient population and

unique treatment setting of ARC.