You first need to focus on a strong thesis statement, something you think you can argue for or against.  Psychopathology is rich in controversy. (I would steer clear of history questions, as there is too much history and not enough controversy.)  “Causes of” would be rich, but best if you already had a strong opinion of its main cause.  The manifestations of psychopathology is too far from the assignment’s objectives.  How about looking at whether psychopathology always manifests in youth—fire obsession, hurting animals, etc.—or whether it can develop later in life, possibly due to an adult traumatic experience or chemical imbalance.  There seems to be a lot to discuss in “Is psychopathology always a childhood affliction?” or something like that.  Good luck—mainly, concentrate your inquiry on a smaller search area.