Doxycycline and suicidality.

A case series outlining three young individuals with no history of mental disorder who were treated for skin conditions with doxycycline, but developed suicidal ideation with an outcome of suicide in two of the cases. One of these individuals had CYP2C19*2 heterozygote genotype associated with a diminished cytochrome p450 enzyme activity and two of his siblings had developed severe anxiety previously while on doxycycline. Another had previously developed mood difficulties on a lower dose of doxycycline which resolved after discontinuation. In the third individual, a discontinuation of doxycycline has led to the resolution of symptoms without the need for psychotropic medications.