Louise O’Neill is an established writer for young adults, with a reputation for hard-hitting books tackling feminist themes. Her debut, Only Ever Yours, won plaudits for its Atwood-esque depiction of a world in which women are bred for male pleasure. The follow-up, Asking for It, addressed the gang rape of a young woman, and won children’s book of the year at the Irish book awards.

As an author widely commended for tackling adult subjects in her YA work, it seems a natural progression for O’Neill to move into adult fiction. Her first such novel is about an exploitative, obsessive relationship between a young woman, Sarah, and the older Matthew. As such, it is a cut above a lot of commercial fiction; this is no bland by-numbers romance. O’Neill ventures into some interesting psychological terrain, such as why Sarah collaborates with Matthew’s unkind, dehumanising treatment, and how this relates to having lost her mother at a young age. She explores the way in which emotions such as grief can be acted out in sexual relationships, sharing this territory with an otherwise very different author, Eimear McBride.

However, the theme of obsessive love does not quite pack the punch that would make this a stand-out popular novel. Sexual dysfunction between consenting adults is hardly a new novelistic area, and O’Neill’s style and characterisation are simple, verging on simplistic. Her dialogue can be clumsy – characters say “Time flies when you’re having fun” and “What’s a nice girl like you doing in a place like this?” But more problematically, Sarah never wins the reader’s sympathies. She comes across as an overgrown adolescent, whiny and morose, and it isn’t clear what she sees in Matthew, other than the ample contents of his wallet.

The most engaging aspect of the novel is its depiction of divided, insecure, post-boom, post-crash Irish society. Sarah has been brought up in a small town with traditional values, which is partly why she is so ill equipped to cope with life in multicultural, materialistic Dublin. It’s a milieu that was more successfully captured by Sally Rooney in last year’s most notable debut, Conversations with Friends.

• Almost Love by Louise O’Neill (Riverrun, £14.99). To order a copy for £12.74, go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min. p&p of £1.99.