I took doxycycline hyclate 100mg twice a day for two weeks for mrsa. It has been two days since my last dose and I haven't been this depressed since postpartum. This depression has been so severe it is debilitating. I was shocked to see it is not written as a side effect when prescribed and relieved to see that so many others have suffered from depression from this drug along with myself. I am hoping that if I continue to eat healthy and exercise I can snap out of this.