Anterior hippocampal volume predicts affect-focused psychotherapy outcome

Area of Science:

• Neuroscience
• Psychiatry
• Clinical Psychology

Background:

• The hippocampus is vital in psychopathology and treatment response.
• Anterior hippocampus (AH) and posterior hippocampus (PH) may have distinct roles in affect-focused versus exposure-based therapies.
• Prior research differentiated AH and PH functions in memory and emotion, but not treatment outcomes.

Purpose of the Study:

• To investigate if hippocampal sub-region volumes predict treatment outcomes in patients with posttraumatic stress disorder (PTSD) and panic disorder (PD).
• To test the hypothesis that AH volume predicts affect-focused treatment success, while PH volume predicts exposure-based treatment success.

Main Methods:

• Structural MRI scans were obtained from 35 PTSD and 24 PD patients before treatment.
• Patients were randomized to either affect-focused (Interpersonal Psychotherapy/IPT, Panic-Focused Psychodynamic Psychotherapy/PFPP) or exposure-based treatments (Prolonged Exposure/PE, Cognitive Behavioral Therapy/CBT, Applied Relaxation Training/ART).
• Anterior and posterior hippocampal volumes were analyzed in relation to clinical outcome changes.

Main Results:

• Baseline whole hippocampal volume did not predict treatment outcomes.
• Smaller anterior hippocampal volume correlated with greater clinical improvement in affect-focused treatments.
• Posterior hippocampal volume did not predict outcomes for either treatment type.

Conclusions:

• This is the first study linking hippocampal sub-region volumes to treatment outcomes in PTSD and PD.
• Findings suggest affect-focused treatments may impact clinical outcomes via the anterior hippocampus.
• These preliminary results require replication in larger clinical trials.