Could Mixture Of 600mg Effexor And 40mg Diasipam Cause Overdosing?

I am wondering if a mixture of 600mg of effexor and 40mg of diasipam is enough for a possible overdose? I have a daughter 19 who is having her meds dispensed by myself daily. I am leaving town for 4 days on business and I must leave behind that amount exactly. Given her recent state of mh , with a breakdown as recent as today, I'm nervous. She's threatened and attempted suicide 3 times since new years 2015. And just for my own piece of mind I would feel comfortable with someone telling me rather than find out when I return home on Sunday.
Thank you!