Making sense of fatigue: the need for a balanced approach

In their recent editorial on fatigue, Newton and Jones [1] comment that ‘the majority of primary care physicians believe that fatigue arises as a consequence of psychological rather than physical factors’ and imply that this may lead physicians to ‘fail before they begin’. They also go on to discuss a biological approach to the investigation and treatment of fatigue, highlighting the need to consider fatigue as ‘real’. While we agree with the need to consider biological processes in fatigued individuals, we contest that any approach that dichotomises the mind and body by focusing exclusively on either the biological or psychosocial aspects of fatigue ignores the current evidence base and is likely to be sub-optimal. We also strongly refute any suggestion that psychological disorders are any less ‘real’ than somatic conditions. Newton and Jones observe that the direction of causation between emotional distress and fatigue has been difficult to disentangle. This is true, but we would highlight the results of recent prospective studies using British birth cohorts which have shown that those with self-reported chronic fatigue syndrome (CFS) had high rates of psychiatric disorder well before the onset of their fatigue symptoms [2]. We also note that other prospective studies have demonstrated that fatigue can occur without psychological distress and that emotional problems may occur as a consequence of chronic fatigue [3]. Randomized control studies have established the effectiveness of cognitive and behavioural focussed therapies in both CFS and fatigue associated with somatic illnesses, such as rheumatoid arthritis, multiple sclerosis and cancer [4–7]. While clearly demonstrating the importance of psychosocial factors, these results should not be seen as evidence of chronic fatigue being a mere consequence of psychiatric distress; there is ample research demonstrating this is not the case [3,8]. Nor should they be seen as diminishing the potential impact of biological factors. We have previously demonstrated changes in immune system activity [9], cortisol levels [10] and autonomic reactivity [11] among those with chronic fatigue, but unfortunately to date attempts to identity a consistent pattern of biological abnormalities, have failed [12–14]. Given this evidence, and the recent recommendations from the UK National Institute of Clinical Excellence [15], we were surprised that Newton and Jones made no mention of psychological factors when they discussed the assessment and management of fatigue. While it is obviously important to consider physical causes, a simple mental state examination remains one of the most productive investigations in prolonged fatigue [5,16]. We agree that a better understanding of the biological aspects of fatigue is essential and share Newton and Jones’ hope that this will lead to novel treatment options. However, we would suggest caution in recommending the widespread use of pharmaceutical treatments based on small (n5 21) open label trials [17], especially given the strong evidence base for other non-pharmacological interventions.