Infidelity, marital breakdown, criminal assault, mental illness. These are topics of high drama; there’s nothing amusing about them. Except that “Silver Linings Playbook” deals with every one — and it is one of the funniest films of the year.

It shouldn’t come as such a surprise. Some of the most droll satirists are also some of the most pensive. Director David O. Russell’s seriously quirky sense of humor has finally found its match, in the Matthew Quick novel on which this film is based.