A dopamine transporter polymorphism is a risk factor for borderline personality disorder in depressed patients.
BACKGROUND
Borderline personality disorder (BPD) is often co-morbid with major depression and may complicate its treatment. We were interested in differences in genetic and developmental risk factors between depressed patients with or without a co-morbid BPD.


METHODS
Out-patients with major depressive disorder were recruited for two treatment trials. Assessment of depressed patients included the assessment of personality disorders, developmental risk factors and DNA samples for genetic analyses.


RESULTS
In each study there was a significant association between the 9-repeat allele of the dopamine transporter (DAT1) and BPD, with odds ratios (OR) > 3 and p < or = 0.02. This association remained significant when developmental risk factors for BPD (childhood abuse and neglect and borderline temperament) were also included in the analyses. The OR was even larger in the depressed patients aged > or = 35 years (OR 9.31, p = 0.005).


CONCLUSIONS
This replicated association in depressed patients between the 9-repeat allele of DAT1 and BPD may provide clues to understanding the neurobiology of BPD. The finding that the association is larger in the older depressed patients, suggests that the 9-repeat allele may be associated with a poorer prognosis BPD, rather than a young adult limited variant of BPD.
Joyce
Peter R
PR
Department of Psychological Medicine, Christchurch School of Medicine & Health Sciences, Christchurch, New Zealand. peter.joyce@chmeds.ac.nz
McHugh
Patrick C
PC
McKenzie
Janice M
JM
Sullivan
Patrick F
PF
Mulder
Roger T
RT
Luty
Suzanne E
SE
Carter
Janet D
JD
Frampton
Christopher M A
CM
Robert Cloninger
C
C
Miller
Allison M
AM
Kennedy
Martin A
MA
D000328:Adult; D001883:Borderline Personality Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D042622:DNA Repeat Expansion / Q000235:genetics; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics*; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D010554:Personality Disorders / Q000175:diagnosis / Q000453:epidemiology; D010555:Personality Inventory; D011110:Polymorphism, Genetic / Q000235:genetics*; D015995:Prevalence; D011379:Prognosis; D012720:Severity of Illness Index; D013694:Temperament
D050483:Dopamine Plasma Membrane Transport Proteins; C493214:SLC6A3 protein, human