LIKE MANY OF ITS PATIENTS, St. Elizabeths Hospital is troubled, unwanted and in dire need of better care. Though it was once singled out as candidate for institutional greatness - to be "national model" of a mental hospital - St. Elizabeths never came close. Today it is aging, unaccredited federal facility run by an acting superintendent and in immediate jeopardy of being dumped on the city to administer.

Even doctrinaire home-rule supporters, while rightly arguing that this hospital should belong to the city, recognise the pitfalls of just turning over the institution as is. Without a formal federal commitment to bring St. Elizabeths up to respectable standards, the city government shouldn't be saddled with this costly burden.

To begin with, the blame for St. Elizabeths' decline rests with the federal government. The Nixon administration sought to turn over the hospital to the city, as a quick and generous-sounding way to show how the federal bureaucracy and payroll could be trimmed. Fortunately the proposal drew considerable opposition ans a special commission was set up to study the matter. But with the fate of the facility thus in limbo, the National Institute of Mental Health has had little incentive to improve its operation there.

Under consideration at a House hearing last month was a bill to place St. Elizabeths under a separate federal corporation, with an authorization for certain federal financing for construction and for operating expenses through 1982. The bill also would mandate increased city financing of the hospital. Federal and city officials alike have testified against this measure - and for good reason. Not only does the bill lack sufficiently specific assurances of improvements in the hospital before the facility could be transfered to the city, but there is no set time by which any such transfer would have to take place. As city council member Polly Shackleton and acting Department of Human Resources director Albert P. Russo stressed in a joint appearance at the hearing, solid federal financial assurances are crucial to any transfer.

Also, there would be no useful purpose served by legislation giving the District Committee or its Senate equivalent another forum in which to exercise authority over local affairs. Far more preferable would be legislation defining certain preconditions for the transfer of the hospital from NIMH to the city - with accreditation heading that list.

Another precondition should be the removal of patients who don't belong in St. Elizabeths. Since 1975, the hospital has been under court order to release more than half of its patients who no longer need care there. Legislation could include a federal authorization for financial assistance specifically to upgrade community facilities needed to accommodate some of these released patients. This could be coupled with a federal subsidy to St. Elizabeths that would diminish over a period of, say, 15 years . Eventually, St. Elizabeths could be turned over by the city government to a local independent commission, as D.C. General is now scheduled to be.