Photosensitivity reactions evoked by systemic agents are the result of the effects of the agent combined with subsequent exposure to light. Photosensitivity induced by exogenous parenteral agents accounts for an increasing portion of the total undesirable effects caused by environmental chemicals. The exponential increase in the number of new drugs introduced each year may be one of the factors explaining the increased number of reports describing photosensitivity induced by exogenous agents. There are many reports of photosensitivity caused by antipsychotic and antidepressant agents. Although the majority of the research was focused on the photosensitising potential of chlorpromazine, other antipsychotics and antidepressants have been shown to cause cutaneous photosensitivity. An extensive drug history must be taken whenever a patient presents with a reaction limited to, or accentuated in, light-exposed areas. It should be remembered that these reactions may present with a wide morphological spectrum ranging from sunburn-like responses to eczematous, lichenoid and even bullous lesions, resembling porphyria cutanea tarda. In order to properly diagnose photosensitivity to systemic drugs it is important to prove photosensitivity by phototesting and to rule out other causes of systemic photosensitivity such as systemic lupus erythematosus and porphyria cutanea tarda.