We live in a therapy culture where sanity is now unattractive, psychoanalyst and author Adam Phillips tells Shane Hegarty

As the interview draws to a close, Adam Phillips asks the question to wilt every journalist's notepad: "Did you like my book? Be honest." As I'm rummaging through my mind for an honest, yet diplomatic answer, it strikes me that one cannot plamás a psychoanalyst and hope to get away with it. He will surely spot a tell-tale inflection, or hear the words that are not said. And my thinking this leads to a lengthy pause into which he could probably read a thousand thoughts.

A practising psychoanalyst, an authority on Freud, and a prolific writer, Phillips's latest book, Going Sane, is his latest examination into notions apparently familiar to us, yet still doggedly elusive. Having previously written about flirting, monogamy, nuisance value (and currently researching "kindness") he has dipped his toe into "sanity", and found it to be somewhat like quicksand. "If you ask people to define sanity they start with the cliches - kind, reasonable, fair. Very quickly they start sounding crazy," he says.

"My assumption is that we're quite interested in some sound psychological alternative to what we think of as madness, but that it's very difficult to articulate it. There's an elaborate language for madness, and I suppose I'm wondering if there's anything else to talk about. Perhaps there's not. Perhaps there's only madness."

In his arrival at a broad, and personal, definition, he is strikingly perceptive on sex, money and illness. He has a particularly novel attitude toward adolescents, suggesting that rather than being written off as crazed by hormones, they may in fact be looking through a window of insight that adults deliberately block up as they get older.

"One of the things a lot of adolescents ask is whether their lives are worth living," explains Phillips, as he stares out the window of his Dublin hotel room. "And that seems to be to me an intermittently pressing question for most people. One of the reasons I wrote the book was it struck me that for most people sanity is a very, very boring idea, but there's one group of people for whom sanity is quite the opposite. And that's people who themselves have been mad or have grown up with mad parents. For them it's an absolutely crucial issue, not something they can be ironic about. And that seems to me to be a very interesting disjuncture here. And adolescence is our vivid picture of this, which is what it's like to be in quite radical disarray and yet feel intensely alive.

"Now, that very feeling of being intensely alive includes feeling intensely dead too. But it means you find yourself thinking the kind of things that are very, very frightening. And it is as though the culture can't bear this or wants it sanctioned off, by saying that this is being an adolescent, not being a person, and it will pass. But what if it didn't? What would it be like if we were more adolescent than we are into our 20s, 30s, 40s?"

He means this as holding onto some of the psychological aspects of one's adolescence and not just being an adult consumer borrowing from teen trends. We can learn from them, he suggests, not least because societies tend to be afraid to discuss suicide, and adolescents have a particular insight into this.

We shouldn't be fooled by the incessant chatter of modern life, he warns. "What psychoanalysis says is that there is a huge resistance to speaking, and one of the ways we conceal this is by speaking a lot."

We live in a therapy culture, in which sanity has become somewhat unattractive in comparison to the promise of rummaging through one's childhood and diagnosing every aspect of one's personality. In the age of Oprah and Trisha, we are even presented with others' psychological problems as entertainment. It's a symptom of political impotence, he says. People are "being put to sleep on quite a grand scale" by the neutralisation of political dissent in capitalist economies, and much modern psychology offers people a chance to be entranced by their own backgrounds and ignore the wider world.

"I think the kind of psychoanalysis I value frees people from introspection in order to share in a communal life. People suffer from being self-preoccupied. What it should be doing is freeing people from their self-preoccupations so they can do something about the injustices in the world. So I think the prevalence of psychology is a very, very bad sign."

The impression he gets from his own practice is that the modern pre-occupations are with parenting, relationships and the daunting question of why it's worth getting up in the morning. In the 1980s and 1990s he spent a lot of time dealing with people who had either made money, or who had made it and lost it. Are there any lessons for the Irish?

"One of the things that seems to be very important is a loss of sense of historical nature of life. For quite a lot of people, one or two or three generations ago, their families might have been very poor and people have quickly, in psychic emotional time, become more affluent. Those who have gained through the system have acquired lifestyles so discontinuous from previous generations, and we're so far ahead of ourselves, that it's as though people are on one hand 21st-century people but on the other 18th-century people. We're living in so many different time periods in ourselves, and that's very difficult to adapt to."

There is false comfort in telling ourselves we've worked hard for the money. "I think we feel guilty because we know that our profit is based on other people's exploitation and suffering. We're not fooled. We sit on something really, really frightening, which is a great deal of misery. And there's no way around this."

Phillips is in Dublin to give a lecture at the Douglas Hyde Gallery on "Freud's Modern Love", which addresses the modern angst over sexual relationships; unresolvable, he reminds us, because Freud pointed out that the power of our passion for our parents is indelible. When we think we are at our most innovative we are in fact at our most repetitious.

"Much as you need to get outside the family to have an erotic life, you keep finding yourself returning to the place you thought you were getting away from. So it's never quite as new as you thought it was." Your wife may not be like your mother, but that's because she might subconsciously remind you of your father.

In Going Sane he writes of how relationships are "not the kind of thing that one can be good or bad at, that one can succeed or fail at, any more than you can be good or bad at having red hair, or succeed and fail at being lucky." He has not changed his mind.

"From my point of view, the way modern life is constructed and lived, you can't make a relationship work by an act of effort or will," he says, "The will can't do that work of imagination in a relationship, and when that happens people grow to hate each other even more," he says.

When a relationship feels like it's over, he believes, it is. We should accept that the man or woman of our dreams isn't someone we could actually have a relationship with, and learn to bear our frustrations. Although, given the implications revealed by Freud, actual sexual satisfaction would be catastrophic. "The point about sex is that it isn't satisfying," says Phillips, "because that's what sustains desire."

• Going Sane is published by Hamish Hamilton, €22