Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. As per your concern regarding comparison of Lexapro, Prozac, Wellbutrin, Celexa. All the drugs almost have similar efficacy in their mechanism of action but there are differences in preference in patient point of view like. Lexapro is generally preferred when there are other issues like hypertension, Diabetes etc as this has minimal interactions with other drugs. Prozac is mostly preferred​ in adolescent depression as it is highly alerting drug among all, initial anxiety might be a concern with Prozac. Wellbutrin is little less efficacious than other drugs but it mainly increases the pleasure and has additional properties that it can be added to other drugs as augmenting agent, so of you are not feeling better with any other single drug, Wellbutrin can be added(under supervision of your Psychiatrist). Tablet Celexa is not preferable generally​ as it has effects related to cardiac system. And regarding fatigue person suffering from severe depression and/or depression generally has dull mood, lack of energy which makes a person feel easily fatigue. And additionally​ has low appetite and digestion capacity, absorption capacity, utilization of absorbed materials will also be very low which ultimately causes fatigue. So, adequate treatment of underlying conditions like depression, anxiety might make you reduce your fatigue. Hope I have answered your query. Let me know if I can assist you further.