Two studies investigated the relationship between headaches (migraine, tension and mixed) and mood. In the first, headache sufferers self-monitored mood and headaches. Results showed that headaches were associated with negative affect more or less equally on all moods measured (anxiety, hostility, depression, unsureness, tiredness and confusion), although there were large individual differences. Mood correlated most highly with headache intensity on the day it was measured rather than the preceding or succeeding days, but the correlation was very small. In the second study, the musical mood induction procedure was used to induce despondency and happiness in headache sufferers and controls. This manipulation provided some support for mood having a causal influence on headaches as the happiness condition was associated with a significant decrement in headache intensity and the despondency condition tended to be associated with an increment in headache intensity. Headache sufferers and controls did not differ in terms of mood response to the induction procedures, hence, providing no support for the aetiological hypotheses that individuals who regularly suffer from headaches are more susceptible to depressive stimuli (and consequently headaches), or are more emotionally labile.