Entries for The Edinburgh Fringe Festival programme have to be submitted by 16th April and I would hazard a wild guess that there will be quite a few performers mentioning Heather Mills, either in their show titles or in their actual shows. I won't include any here, but just google the words "Heather Mills Joke". There's no shortage of painful puns and brutal barbs clogging up cyberspace.

Ever since she married Paul McCartney, Heather Mills has been the butt of umpteen gags and I suspect that given her "interesting" personality and her "interesting" past this would have been the case even if she still had her two original legs. But given her physical condition, everyone from professional comedians to pub wags have had a field day. It seems acceptable to pick on her in the same way you can say Americans are idiots but not the Irish. You can only make cruel, tasteless jokes about oppressors not the underdog and the uber-assertive Mills definitely felt like an oppressor.

So what will Heather Mills do now? Somehow I can't see her taking her £25 million and going off quietly into the night. I assume she'll be offered the usual I'm A Celebrity chances of celebrity redemption. The comedy world must certainly be hoping she won't be going all reclusive on us because she is such great value. In fact I've just thought of a great way in which Heather Mills could get her own back on the comedy community. Come on Heather, that deadline for Edinburgh shows is still three weeks away. Why not do your own show?

I saw a very funny clip the other day of Iggy Pop doing a version of Madonna's Ray of Light at the Rock and Roll Hall of Fame. All was going swimmingly until he jumped into the audience and started bellowing in the faces of the front row. Which would have been fine if this was your normal gig, but these people were mostly middle-aged (albeit younger than the Igster) and wearing tuxedos and dickie-bows. Their responses were a mix of boredom and sheer fear.

As a comedy fan I could relate to this. Some of my most excruciating experiences have been at comedy gigs where the performer has broken down the fourth wall and strolled into the crowd. As a notebook-brandishing critic I always dread that moment when one of them spies my pen and paper. So far I've been lucky, but there have been some close shaves. Madcap Irishman Jason Byrne once saw another critic in the crowd and said that he should make notes on his scrotum as it would be more discreet than using a notebook.

At Little Britain's Hammersmith Apollo show Matt Lucas paused right by me when he was dressed as Marjorie Dawes and looking for someone to weigh onstage as part of his Fat Fighters sketch. Fortunately I wasn't fat enough. In Croydon last autumn Russell Brand stood so close to me while eyeing up potential sexual conquests he almost garrotted me with his microphone lead. Luckily I'm not his type.

Stewart Lee took a more kind, considered approach, strolling up the aisle at the Soho Theatre without picking on anyone at all. Unlike spoof trolley dolly Pam Ann, who hurtled up and down the steps looking for someone to drag onstage. Pam, as always, managed to scare the beejesus out of me without actually coming within five feet.

Sometimes, of course, stepping into the audience can make a fan's day and maybe even make a show. In Phil Nichol's if.comedy-winning set Naked Racist he roamed through the audience completely nude to rapturous applase from everyone. I even clapped myself, but then I was safely on the far side of the room. I'm not saying that it helped him to win the award, but it certainly showed that he had something every successful comedian needs. Balls, in every sense of the word. Maybe I should have made my notes on them.

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.

Depending on what newspaper you read Dawn French and Jennifer Saunders' current tour is either their last ever live tour, the last time they will perform together or possibly even the last time Dawn French will get up onstage before she retires to a quiet life eating Chocolate Oranges in the West Country.

The Evening Standard will be reviewing the show when it reaches the south of England later this month, but early reports from the northern leg of their first outing in seven years suggests that it is pretty good. At their advanced age they may not be winning over any new fans but they are certainly satisfying the ones they have with a mix of Madonna spoofs, Catherine Zeta-Jones send-ups and Abba songs.

I'm not even going to enter into a debate about whether women can be funny at this juncture (answer: yes, even though at a recent talent competition I was judging, when the second woman came onstage halfway through the show a man behind me said "Oh no, not another bloody woman"). What I'm interested in is the nature of double acts.

I guess the obvious comparison is with marriages. Some last longer than others and there are inevitably arguments. Sometimes the spark just goes. One performer I interviewed described a double act as "like a marriage but with less sex."

French and Saunders seem like a couple who have never had a cross word, yet even they have decided to, as it were, "see other people", ie pursue other projects. Maybe it runs in the family. A couple of years ago Ade Edmondson, aka Mr Saunders, decided to knock his slapstick double act with Rik Mayall on the head. Which was apt, because they'd been knocking each other on the head for years. They are still mates and may well still work together again, but don't hold your breath waiting for another series of Bottom.

Another intriguing case study is Vic and Bob. While they haven't actually split and last year did an enjoyably daft Radio 2 series together, Vic Reeves has frequently been working solo in recent years. But even as his most ardent fan I'd be hard-pushed to say that anything he has done without Bob Mortimer has come close to the giddy heights of their toweringly silly Big Night Out.

Of course, double acts will invariably want to try different things and you only live once, so who can blame them for branching out? It has happened with Peter Cook and Dudley Moore, Baddiel and Newman and pretty much any double act you can think of. In fact Morecambe and Wise might be the only high profile duo whose career together ended due to death.