Are today's comedians sad, tragic figures? According to The Curse of Comedy, the forthcoming series of BBC4 dramas starting on 19 March, about Tony Hancock, Frankie Howerd – played by David Walliams – Harry H Corbett and Wilfrid Brambell (and, erm, Hughie Green...) certain old school entertainers were certainly pretty troubled – a laugh-a-second onstage but hell to be with off-duty.

So what about today's bunch? For the sake of legal bills I'd better not name any of the following people but my experience over the years is that the current wave of successful comedians might not be as miserable as the clowns portrayed in the BBC4 series, but they are certainly a dysfunctional bunch.

Some comedians might be the life and soul of the party and love being the centre of attention, but one friend told me about how she dated a high-profile funnyman for a while and rented a cottage with him and some of his stand-up chums. It was, she recalled, the most excruciatingly miserable experience of her life. No wisecracks around the fireplace at all, just silences and a lot of moaning.

When I've interviewed comedians they've put on their brightest, shiniest faces, but many have another side to them. A lot are charm themselves, but can still be incredibly demanding on set. Some call this being a perfectionist, others call it being a pain in the neck and there is probably a thin line between both judgments.

One famous comedian, who seems pretty normal whenever I interview him, has often been in the tabloids thanks to his alleged lurid sexual exploits. I'm sceptical about tabloid stories, but I was told that everything I'd read about this chap was true. Then again, if these stories are true he is hardly gloomy and depressive, he sounds like he is having a brilliant time.

Enough comedians have been in and out of the Priory over the years to suggest that they have their fair share of emotional issues. I guess part of the problem is the contrast between the acclaim onstage for about an hour a night and the loneliness of life on the road. Wasn't it that great stand-up comedian Janis Joplin who said something like "I've just made love to a thousand people but I'm going home alone."

There must be some truth to the myth of the miserable jester. We are fascinated by the whole idea of tears behind the laughter. Maybe there is a connection between wanting to make people laugh to fill a void in your soul. There's the famous story about a man going to see a psychiatrist because he was depressed. The psychiatrist advised him to go and see "the great clown Grock", who was currently performing in the city. Grock would cheer him up. The depressed man replied: "That's the trouble. I'm am Grock."

Then again, maybe it's just the nature of human beings to be dysfunctional. I've also met a few moody plumbers in my time and the man in the my local stationery shop is not a bundle of laughs. And I suppose if I moved in dentistry circles I'd have met a few unstable dentists. It's just you don't get the BBC making dramas out of depressed dentists.