Traditionally in the American Catholic Church Catechesis is something that is done to children. While our Protestant brothers and sisters long ago embraced the concept of adult faith formation, most commonly reflected in the ubiquitous "Sunday school" which nearly every Protestant congregation attends before or after services, Catholics have generally limited their concept of formal catechism to children and teens.
At one time this might have been justifiable. Catholic workers of the nineteen century were generally satisfied to leave matters of theological importance to the priest. Society reflected a general Christian, if not Catholic, set of moral principals, and though in most working class Catholic homes one of the few books likely to be found was the bible, actually reading the bible was not a well practiced trait among the laity.
That a good number of the laity, as the nineteenth century gave way to the twentieth century, had the fortunate exposure to Catholic parochial schooling also meant a large exposure to resources like the Baltimore Catechism during the formative years, meant that most retained at least a solid base of knowledge of Catholic doctrine.
The post Vatican II period changed that. Note I am not blaming Vatican II for the change. The cultural shifts that took place in the 1960's-1970's were not the result of Vatican II. The lack of Vatican II could no more have prevented those shifts than the existence of Vatican II caused them.
No matter the stand on that subject the reality is that a large segment of the Catholic adult population lacked a fundamental foundation of knowledge of Catholic doctrine. At the time the Church seemed unprepared for dealing with the problem. The beloved Baltimore Catechism was banished, but no authoritative document replaced it. It was not until 1997 that the Catechism of the Catholic Church was published. Unlike the Baltimore Catechism, which was written in a question and answer style, the CCC was written in a style more reminiscent of a textbook. While unquestionably authoritative the CCC was not conducive to casual reading.
Meanwhile in parishes there was a move afoot to reach out to adults. This was often in the form of bible study classes, and small Church Community groups. These groups were most often lead by the laity, and while very enriching for the participants often failed to move beyond the Sunday readings into wider Church doctrine.
Today there is a another trend, which if not sweeping the country, is at least widely found. That is the move toward parish wide faith formation. These programs bring in families, as well as young adults to cover a wide range of topics relevant to Church doctrine. They are often enriched by the participation of priest and deacons (especially deacons) who are knowledgeable in theology, but they also bring in members of the laity to act as catechists, not of children or catechumenates, but to adult Catholics seeking to increase their knowledge of the teachings of the Church.
The success of these programs hinge on the ability of parishes to get their parishioners to spend more than fifty-five minutes a week on God. How to do it? Some suggestions coming.