Psychotic syndromes in the context of hyperthyroidism are seldom mentioned in medical textbooks and only a few cases have been published. Typically, such cases present as an affective psychosis. Schizophrenia-like psychosis is a rare occurrence in hyperthyroidism and the link between these two conditions is still poorly understood. We report the case of a female patient with a known history of chronic lymphocytic thyroiditis. The patient presented to our emergency department with an acute schizophrenia-like psychosis. Elevated levels of T4 and free T4 were found. These resulted from the patient's voluntary intake of excess levothyroxine as an attempt to lose weight (thyrotoxicosis factitia). Normalisation of thyroid hormone levels and antipsychotic treatment led to prompt remission of the psychosis. Even though the patient stopped the antipsychotics, she remained free of symptoms during the follow-up. Similar cases are briefly reviewed and some of the data from basic research is also considered.