BDNF and major depressive disorder: Kohli et al. [151], trying to determine whether the BDNF gene or its high-affinity receptor gene, receptor tyrosine kinase 2 (NTRK2), confer risk for suicide attempt and major depression, found that in 394 depressed patients, of whom 113 had suicide attempts, independent single-nucleotide polymorphisms within NTRK2 were associated with suicide attempts among depressed patients.