Can the security alarm drain the battery.

What is your question?

I'm not sure if the alarm system is factory or after market. I don't have a remote and rely on the toggle switch to turn turn it off. Now all the sudden if I move the switch the horn goes continuously. When I start my car it does something weird and the battery is drained. Had my battery checked and its good. Can't get a test on my alternater because it has to be jump started at the time I need to start it for the test. Would like to disarm the alarm. It makes the car unreliable.