You can but only in. Moderation. As you might be aware, alcohol and Celexa (citalopram) can interact. They both act upon your brain’s neurotransmitters. Alcohol is a sedative that works with GABA and Dopamine receptors. Alcohol can ruin the antidepressant effects of celexa, (citalopram) which works with serotonin receptors. So, if you want to drink some alcohol, it would be best to drink in moderation.
Conditionally yes. Both affect your brain and the mixture can cause severe side effects - confusion, inhibition to the point of lethal outcome etc, especially if alcohol is abused. If you have a glass of beer or wine, it will probably not affect you very much, but again, be extremely cautious.