Although clinical depression is an exhaustively-researched phenomenon, the effect of medication may have compromised many previous studies. Some research shows that medication and its side effects reduce a range of psychological and physiological functioning: unfortunately, the impacts of medication are poorly documented. This book, examines personality, brain electrical activity and neuropsychology functioning in medication-free clinically depressed patients. Participants consisted of 22 clinically depressed patients all of whom were medication-free and diagnosed with Major Depression. The results supported hypotheses relating to personality but not for those relating to brain electrical activity or cognitive functioning. The most important inference drawn from the research was that personality, cognitive deficits and brain electrical activity are related to each other suggesting that cognitive effort may be important in multiple areas.