Atypical, or second-generation, antipsychotics are the first line of defense in the treatment of schizophrenia and psychosis. One of the main side effects of treatment with antipsychotics is weight gain. Weight gain can lead to the development of a variety of conditions such as insulin resistance, diabetes, dyslipidemia, and increased cardiovascular risk. Over the past few years many studies have demonstrated that this weight gain is not only due to changes in metabolism but that treatment with antipsychotics can also induce hyperphagia through currently unknown molecular mechanisms. We developed a powerful microtiter-plate based system to measure food intake in C. elegans and have found that antipsychotics also induce hyperphagia in worms. The conservation of this phenotype allows us to take full advantage of the power of C. elegans as a model organism to study the genetics of antipsychotics-induced hyperphagia. We have used this system to analyze the signaling pathways involved in antipsychotics-induced hyperphagia, in addition to studying the effects on food intake in mutant C. elegans with defects in orthologues of human genes known to be affected in response to antipsychotics treatment.