Alpha/theta neurofeedback has been shown to be successful both in treating addictions and in enhancing artistry in music students. How its effects are mediated are not yet clear. The present study aimed to test the hypothesis that alpha/theta neurofeedback works inter alia by normalising extreme personality and raising feelings of well being. 12 participants with high scores for Withdrawal (as measured by the PSQ) were given either alpha/theta neurofeedback or mock feedback and their personality and mood were assessed. Withdrawal scores on the PSQ-80 were not found to change in either group but significant effects were found for the Profile Of Mood States (POMS), with real feedback producing higher overall scores than mock feedback (P = 0.056). Real feedback caused participants to feel significantly more energetic (P < 0.01) than did mock feedback. Sessions of real feedback made participants feel more composed (P < 0.01), agreeable (P < 0.01), elevated (P < 0.01) and confident (P < 0.05), whilst sessions of mock feedback made participants feel more tired (P < 0.05), yet composed (P < 0.01). These findings suggest that, whilst 9 sessions of alpha/theta neurofeedback was insufficient to change personality, improvements in mood may provide a partial explanation for the efficacy of alpha/theta neurofeedback.