Crazed commuters, fretful parents and overwrought executives are not the only ones to suffer from anxiety — or to benefit from medication for it. The simple crayfish has officially entered the age of anxiety, too.

This presumably was already clear to crayfish, which have been around for more than 200 million years and, what with predatory fish — and more recently, étouffée — have long had reasons to worry.

But now scientists from France have documented behavior in crayfish that fits the pattern of a certain type of anxiety in human beings and other animals. Although the internal life of crayfish is still unknown, the findings, reported on Thursday in the journal Science, suggest that the external hallmarks of anxiety have been around for a very long time — and far down the food chain.

Beyond that, a precursor of Valium changed the behavior back to normal. That does not mean that the crayfish are ready for the therapist’s couch, but it does reinforce the sometimes surprising connections humans have with other living things.