Figure 4From: Psychological pain treatment in fibromyalgia syndrome: efficacy of operant behavioural and cognitive behavioural treatmentsDifferences in affective distress among cognitive behavioural therapy (solid line), operant behavioral therapy (dashed line), and attention-placebo (dotted line) groups prior to treatment (T1), immediately after treatment (T2), and at 6- (T3) and 12-month (T4) follow-ups.Back to article page