Ishida's works feature three major themes: Japan's identity and role in today's world; Japan's social and academic educational structures, and Japanese people's struggles to adapt to social and technological changes in Japan's contemporary life.Art
He conveys isolation, anxiety, identity crisis, skepticism, claustrophia and solitude, incurred by these themes, by making school boys and business men as part of a factory and portraying young people, mostly young men, as physically integrated with everyday household objects. Such as a wash basin, a radiator, a toilet and a desk. His subjects have faces that resemble Ishida's own face. The resemblance suggests these are autobiographical, but Ishida had firmly denied this.
Ishida shared anecdotes of his parents expressing bewilderment over his art style and the dark nature of his works. His mother was particularly upset by one of his self-portraits as she felt it was too dark, but he assured her that it was him at his happiest because he felt he could communicate better through his painting than he could in person. He later reported that his parents came to accept his works as part of his personality and that they, particularly his father, were able to appreciate his works even though they still didn't understand his art.
In a snippet from an archived television interview used during Tokyo TV's Kirin Art Gallery's feature "The Grand Art Masters", Ishida had stated that regardless of whether he liked painting or not, he felt compelled to continue painting "people at mercy of Japan's contradicting nature of its social systems for as long as they exist". He commited suicide by standing in front of a train.