For stimulants such as Methylphenidate and coffee, it is at least an hour, so I read:
Stimulant + Stimulant = Stimulated. Don't take your Concerta with coffee in future. Space them out at least an hour or so.
To be safe I do at least three hours.
What about antidepressants? Is it safe to take to take antidepressants and coffee at the same time?
Safe is used in relation to that taking coffee with Methylphenidate is not safe due to the synergy or whatever.
what is the medically advised time between taking an antidepressant and coffee?
There is no such time, and there cannot be. All we know is that there are negative consequences when you take them together. We know that there are must be spacing schedules when the consequences must be milder than with other schedules. But we have neither the data nor the mathematical models needed to make a prediction about which waiting time minimizes the negative consequences.
The first problem is in the effect you were interested in initially: they are both psychoactive drugs, changing your mood and cognition. If you combine them, the effect can be stronger, or weaker, or you can experience changes which you wouldn't have experienced if you were taking only one of them. But this kind of thing is very, very hard to measure. A cursory search doesn't even find a study which seeks evidence for such interaction, much less trying to find consistent patterns in this interaction or investigating its time dimension.
The second problem is that there is also a metabolic interaction, described in arkiaamu's answer. This means that the metabolism rate of each drug (which already has a very wide spread between individuals) changes the metabolism rate of the other! Predicting how it develops in a given individual will take as much effort, computational time and data as predicting the weather for a given location. It's certainly not possible to derive some general rule.
So, all we know that it will have some negative consequences. What you also asked is if there is a "coffee must not be taken at all" rule. If you were to just look at the interaction between coffee and antidepressants, then yes, you should stop drinking coffee at all, because you cannot avoid the interaction.
But such a view would be very short sighted. Coffee has both positive effects such as being a source of antioxidants and improving alertness and negative effects, subsumed in one study as indigestion, palpitations, tremor, headache and insomnia. None of these has some standard quantification so that one could say that medically, the risks are more than the benefits, or the other way round. Now, with the interaction with antidepressants, you are adding one more negative effect. Still, the situation is the same: we cannot measure whether it is better to take the caffeine or not take it.
In the end, it is similar to all matters in nutrition. We know that what you choose to do will have some effect, but the effect is so complex that it is impossible to make a prediction of what it will be exactly, and derive specific advice based on that.
Well it depends on what antidepressant you are taking.
Caffeine works as a substrate and as an inhibitor for an enzyme called CYP1A2 (1). As so, metabolism of all other drugs which are processed by CYP1A2 enzyme are possibly influenced by administration of caffeine.
Following antidepressants are processed by CYP1A2 (2):
The interaction between fluvoxamine and caffeine has been shown to exist in humans (3).
Interaction between caffeince and others antidepressants has not been investigated in humans but animals tests have shown significant interactions (4,5). No reason to assume that these interaction would not exist in humans.
It seems reasonable not take coffee and aforementioned antidepressants at the same time.
