The present study explored the explanatory power of Mittenberg's “expectation as etiology” theory for the persistence of postconcussion syndrome (PCS) complaints. One hundred forty-one participants completed a PCS symptom checklist under 2 conditions. Normal controls, healthy athletes and depressed individuals reported current symptoms and symptoms expected following a hypothetical mild head injury. Head-injured athletes, chronic headache sufferers, and a 2nd sample of normal controls reported current symptoms and retrospective symptoms (prior to their injury/illness or from some point in the past). Depressed individuals reported more current symptoms than normal controls and healthy athletes, demonstrating that “PCS” symptoms are not specific to PCS. All groups expected more symptoms following mild head injury than currently experienced, supporting the idea that individuals expect negative consequences following head injury. However, healthy athletes expected fewer symptoms than normals or depressed individuals, possibly due to preexisting expectations for speedy recovery. Both head-injured athletes and headache sufferers reported more current symptoms than the past, but not at a rate lower than baseline of normal controls. Results suggest that the “expectation as etiology” hypothesis may be too specific, and that, following any negative event, people may attribute all symptoms to that negative event (the “good old days” hypothesis). (JINS, 2001, 7, 323–333.)