Is catnip safe for kittens? There is no evidence to suggest that catnip is in anyway harmful to the brain of cats, either kittens or adults. I take that conclusion from books that I have and from the internet.
The respected book ‘Cat Owner’s Veterinary Handbook‘ says on page 222 (3rd edition) that ‘Young kittens and about one-quarter of all adults cats are unaffected…’ By implication the respected veterinarians who wrote the book accept that kittens can enjoy sniffing and chewing on catnip.
Dr Bradshaw in Cat Sense writes that ‘A single gene governs whether or not the cat responds [to catnip], and in many cats, perhaps as many as one in three, both copies of this gene are defective, with no apparent effect on behaviour or general health‘. The author makes no references to catnip being harmful in anyway and does not mention the need to protect kittens.
However, I am obliged to be brave and speculate on my personal answer. In my view, not enough is known about catnip and its affect on the cat’s brain to be able to say with complete certainty that it is alright for kittens to ‘use’ the drug. In fact we don’t understand at a detailed brain chemistry level how the ‘drug’ works. And of course we can’t interview a cat to check her general mental health.
How do we know if catnip affects mental health? My personal theory is that we should not interfere with our brain chemistry using chemicals and this should or could extend to our cats. However, I have let my cat sniff catnip because when you buy scratching boards and posts you use catnip to encourage your cat to use the board. And advocates of catnip will say it provides enjoyment and that is a benefit to e.g. a bored indoor cat.
My assessment is based on how humans should protect children from the potentially harmful effects of drugs. But this is probably an erroneous way to proceed.
The conclusion, really, is that catnip is safe for kittens as far as we know. Catnip can affect all cats both wild and domestic no matter their size.