Bulimia nervosa with co-morbid avoidant personality disorder: behavioural characteristics and serotonergic function

Area of Science:

• Neuroscience
• Psychiatry
• Behavioral Science

Background:

• Lowered serotonin function is linked to interpersonal submissiveness and bulimia nervosa (BN).
• Avoidant personality disorder (APD) is a potential proxy for submissiveness.

Purpose of the Study:

• To investigate the impact of co-morbid APD on behavioral inhibition and serotonin function in women with BN.
• To explore the relationship between submissiveness, behavioral inhibition, and serotonin function in BN.

Main Methods:

• Compared three groups: women with BN and APD (BNA+), women with BN without APD (BNA-), and controls.
• Assessed psychopathology, eating disorder symptoms, behavioral inhibition via a computerized task, and serotonin function via prolactin response to m-CPP.

Main Results:

• The BNA+ group exhibited higher submissiveness, social avoidance, emotional restriction, affective instability, and self-harm.
• BNA+ participants showed increased behavioral inhibition to punishment cues and blunted prolactin response to m-CPP.
• No differences were found between bulimic groups in current eating symptoms or other mental disorders.

Conclusions:

• Women with BN and co-morbid APD display interpersonal submissiveness, avoidance, affective instability, self-harm, behavioral inhibition, and reduced serotonergic sensitivity.
• These findings suggest shared serotonergic mechanisms underlying social submissiveness, threat-related behavioral inhibition, and BN.