A STURDY SIX-YEAR-OLD comes to visit his country cousins; he's from Brooklyn and informs them, before he gets in the door, that boys from Brooklyn are tough. They greet this with the skepticism natural to peers and relations, but his next statement sends them reeling: "I've got a psychiatrist," says the six-year-old, "because I've got problems." We are indeed living in what Martin Gross calls the "Psychological Society."

Gross has taught social history at the New School and New York University, in an area where mental health is sedulously tended, since more than a quarter of all the psychiatrists in the United States live in the city and environs. There are more psychiatrists in two buildings in New York than in 17 of our states - in 1970, one for every 3000 men, women, and children in New York as compared to, say, one per 33,000 in West Virginia. That is a greater concentration of psychiatrists (let alone psychologists and other assorted therapists) than anywhere else in the world. With one exception: Washington, D.C.

Does this mean that the concentration of sick and troubled people in Washington is 20 times greater than in the stricken hollows of Appalachia? Indeed not. Tempting as this hypothesis may seem, formidable as its explanatory power may appear to a citizenry trying hard to figure out what goes on in the nation's capital, it means only that Washington contains more people with an assured means of payment (often, as with the uniquely generous mental health benefits of the federal employees' insurance plan, subsidized by the taxpayer) and the conviction that the thing to do when you have problems is to take them to a professional at $50 an hour.

Gross says that mental illness - the real thing - "has not increased significantly since 1955, when complete records first began." Yet "the demand for psychoterapy is non-ending. It's unbelievable," a New York analyst told Gross. "Individual psychotherapy was once an elitist privilege, but it has been democratized. The general population now feels entitled to it . . . In prior times, people would take care of ordinary life crises by themselves, or with the help of their families. Now they all want psychotherapy." Our psychological society, says Gross, has performed a sematic trick; it has equated happiness with normality, "taken the painful reactions to the normal vicissitudes of life . . . and labeled them as maladjustments." Thus, "we have massively redefined ourselves as neurotic, particulary when life plays its negative tricks." The American belief in human perfectibility noted by Tocqueville has come together with the American belief in methodologies to fill the void left by declining faith. Gross calls the result "the educated man's opportunity to practice religion under the cloak of science." Psychology and psychiatry, he says, "offer mass belief, a promise of a better future, opportunity for confession, unseen mystical workings and a trained priesthood . . . devoted to servicing the paying-by-the-hour communicants" who are enthralled with tales of "sex, mystery, love, martyrdom and conflict" that rival The Greatest Story Ever Told. In contrast to the Bible, however, the hero of this story is oneself: "To egocentric modern man, the prospect of Self instead of God seated at the center of a world philosophical system is exquisitely attractive."

Because of its tremendous influence, both therapeutic and cultural, Gross reserves his biggest artillery for classical psychoanalysis. Not only is it a religion which, posing as science, "has for a half-century helped to block much true research in psychiatry by diverting . . . the talented" from less fanciful investigations. It is also, as religions go, "distorted and unloving," suffused with Freud's own reductive view of man and projecting his own personal needs and conflicts onto all humanity. Freud developed his theory of infantile sexuality without troubling to observe any infants. "Why do I not go into the nursery and experiment?" he asked Fliess. "Because with twelve and a half hours' work and no time and because the womenfolk do not back me in my investigations." Gross tramps into the very Holy of Holies; a man who can doubt the Oedipus Complex probably doesn't even believe in flying saucers. Yet he is not alone; "Nonanalytic professionals are baffled by the complex, which is supposed to be universal in five-year-olds, but is rarely seen in nonanalytic psychiatric work." And the distinguished Washington psychiatrist Paul Chodoff and others suggest that "the Oedipal wish is probably a rare pathology of distorted mother-child relationship."

To quote only the striking generalizations from Gross's book is to make him sound what he is not - soreheaded and sensational. This is no top-of-the-head broadside, but is crammed with summaries of well selected research and quotations from distinguished psychologists and psychiatrists. (One such, Dr. Robert Spitzer, explains that the term "neurotic" will not appear in the new edition of the American Psychiatric Association's official diagnostic manual - unless the analysts pull it back in. It's meaningless.)

The Psychological Society is a breathless tour of the funhouse and no one matter gets all the discussion it needs. It is impossible to present a convincing, balanced refutation of Freudian theory and practice in two short chapters. But good notes make is possible to track things down when, as often happens, you come across something that seems past belief. (Gross pillories nobody; particularly absurd statements, when from living sources, are generously unattributed.) So when Gross tells you that study after study of psychotherapeutic outcomes shows that two-thirds of patients in therapy get better - but so do two-thirds of the people on the waiting list who never got treated - and that one study shows 1 in 10 actually harmed, you can believe him, or look up the studies for yourself, in which case you'll find him accurate. He's a little unappreciative of the educational function of psychotherapy for those who go into it not because, like so many boys from Brooklyn, they've got problems, but in obedience to the ancient exhortation to "Know Thyself." Depending on how absorbing you find yourself (many analysts today are nothing a rise in the condition known as narcissism), there are interesting things to be learned in the 50-minute hour, not all of them entirely absurd. But this is an important, responsible, comprehensive book; and one in which Washingtonians, unless statistics lie, should have a very particular interest.