The association between brain-derived neurotrophic factor Val66Met variants and psychotic symptoms in posttraumatic stress disorder.

Objectives: Psychotic symptoms frequently occur in veterans with combat-related posttraumatic stress disorder (PTSD). Brain-derived neurotrophic factor (BDNF) plays a major role in neurodevelopment, neuro-regeneration, neurotransmission, learning, regulation of mood and stress responses. The Met allele of the functional polymorphism, BDNF Val66Met, is associated with psychotic disorders. This study intended to assess whether the Met allele is overrepresented in unrelated Caucasian male veterans with psychotic PTSD compared to veteran controls.

Methods: The BDNF Val66Met variants were genotyped in 576 veterans: 206 veterans without PTSD and 370 veterans with PTSD subdivided into groups with or without psychotic features.

Results: Veterans with psychotic PTSD were more frequently carriers of one or two Met alleles of the BDNF Val66Met polymorphism than veterans with PTSD without psychotic features and veterans without PTSD.

Conclusions: The study shows that veterans with psychotic PTSD carried more Met alleles of the BDNF Val66Met than non-psychotic veterans with PTSD or veterans without PTSD. The results might add further support to the hypothesis that psychotic PTSD is a more severe subtype of PTSD.