CHICAGO (AP) _ A settlement has been reached ending a probate court lawsuit against the former head of the American Psychiatric Association, who was accused of exploiting a wealthy patient, a court official said Tuesday.

The settlement was reached and approved by Cook County Circuit Judge Frank Petrone on Nov. 4, two days after Petrone declared a mistrial, abruptly excusing a three-member jury in the midst of opening statements.

The case stemmed from a 1984 lawsuit filed by Francis Lederer II, the only child of Anne P. Lederer, who sought to overturn his mother's will.

Mrs. Lederer left most of her estimated $5 million estate to a non-profit institute she established four years earlier to promote psychiatric research and music. None of the money has been paid, however, because her son was contesting the will.

Among other bequests, the will also left $200,000 to her son and several thousand dollars to two grandchildren.

Dr. George Pollack, one of Chicago's leading psychoanalysts and past president of the American Psychiatric Association, was one of the executors of the will.

Lederer's lawsuit contended Pollock improperly used his influence while treating Mrs. Lederer for depression, urging his mother to create the institute and inducing her to bequeath much of her fortune to it.

Pollock denied the allegations in an affidavit in 1986.

Lederer accepted a $1 million settlement, paid out by the research institute, his attorney, Philip Doran, said Tuesday. Attorney Richard Phelan, who represented the institute, did not return telephone calls Tuesday.

Mrs. Lederer set up a fund in 1976 that has paid Pollock $50,000 a year and will continue paying him through 1993. She established a second trust that has paid Pollock's family $30,000 a year since 1978. Court records do not make clear when the second trust expires.