Some critics, like Laura J. Hartman, think that Laura's experience at the "Goblin Market" is similar to drug addiction. This reading makes some sense. After eating the fruit, Laura can't think about anything but her next fix (that is, her next taste of goblin fruit). Her final recovery can only occur after eating some of the goblin juice her sister brought back for her. This might be akin to how the withdrawal symptoms of heroin addiction are sometimes treated with methadone, a chemical similar to heroin but less harmful.
Questions About Drugs and Alcohol
Why can't Laura hear the goblins after tasting the fruit for the first time?
How does the fruit juice that Lizzie brings her bring about Laura's recovery?
What passages in "Goblin Market" suggest that Laura is physically, as well as emotionally, addicted to the goblin fruit?
Chew on This
Although most modern critics read Laura's over-indulgence in the goblin fruit as a metaphor for a sexual fall, her symptoms are more analogous to drug addiction.
The parallels between Laura's condition and the physical effects of addiction can be traced to Rossetti's biography: depression ran in her family, and her sister-in-law, Elizabeth Siddell Rossetti, eventually died of an overdose of laudanum.