Mood

Fatigue | Mood | Cognition | Epilepsy

Mood

Diagnosis
Providing a psychiatric diagnosis for a brain tumour patient fulfils several functions, including giving a name for the symptoms the patient is experiencing, and the legitimising of a trial of evidence-based medical and/or psychological treatment in the hope of alleviating symptoms and improving quality of life. Historically, psychiatric diagnoses were largely impressionistic and derived from speculative (but highly influential) Freudian theories. This diagnostic process, in its heyday in the mid-20th century, was by definition subjective and (at a population level) low in reliability.



Currently, and in an effort to increase reliability, diagnoses are operationalised. Psychiatrists are generally encouraged to diagnose disorders by seeking and recognising certain key symptoms (without which the disorder cannot be diagnosed), and which are present in combination with others from a larger list of possible additional symptoms. So for depression, the ICD-10 specifies three symptoms as core to the disorder, at least two of which must be present: low mood, anhedonia and fatigue. Additional to these, in varying degrees, may be changes in sleep, appetite or psychomotor activity, poor concentration, low confidence, guilt, and suicidal thoughts. As far as is possible value judgements as to the cause or justifiability of symptoms are avoided because these would introduce variability and bias. The intention is to standardise the diagnostic process as far as is possible.



Inevitably, if followed to the letter the effect of such an operationalised approach is that some degree of human leeway may be lost. There is a well-recognised risk of medicalising normal human suffering by taking such a reductionist approach. Questions also remain as to whether the current list of depressive symptoms accurately reflect a discrete pathological entity; a real disease, or whether some symptoms are either superfluous or missing. As a result the approach is not without its critics. However, for want of something better it is the currently accepted international standard.



Challenges

It can’t be denied that operationalised diagnoses present a challenge in diagnosing depression in patients with brain tumour. It is possible to argue - often persuasively - that the first of the key symptoms (depressed mood) can be viewed as a normal reaction to the many losses that inevitably accompany the diagnosis of a brain tumour. This mindset can be summed up in the aphorism ‘I’d be depressed if I had a brain tumour’. Of the other two cardinal ICD-10 symptoms of depression, anhedonia may be caused in particular by lesions to various pathways in the frontal lobe, and fatigue is the single most frequently-reported symptom in surveys of brain tumour patients, depressed or otherwise. Likewise altered appetite, disrupted sleep, psychomotor changes, poor concentration, and low confidence can usually be easily attributed to the tumour or its treatment, if one is so inclined.



Clinicians may feel more comfortable and even professionally validated in retaining for themselves the right to judge whether symptoms of depression are understandable and therefore do not need treatment. However it is important to bear in mind that the biological nature of depression is largely obscure. Despite the comforting gravitas both of the term ‘Depressive Disorder' and having an internationally-agreed list of symptoms, we don’t really know what depression is, at a molecular level. Adopting any sort of value-driven stance as to the treatability, or otherwise, of symptoms may therefore be premature. If the level of disability is high and symptoms are pervasive and consistent, a better question may be: ‘Does this patient have symptoms for which there is an evidence-based treatment?’



RCTs

Unfortunately to date, no Randomised Controlled Trial has examined whether antidepressants are effective in treating clinical depression in the presence of a large infiltrative tumour that is disrupting brain function. Likewise, no RCTs have examined which psychotherapeutic interventions are of demonstrable clinical value in patients who have received chemotherapy and cranial radiotherapy, are consequently cognitively impaired, and have a relatively short prognosis. The lack of evidence is due partly to the practical difficulty of studying these questions, coupled to a sense that the issue is of less than the highest priority for competitive cancer research funding. In the UK, the closest we currently have to an official guideline in this area is probably the NICE guidance on the treatment of depression in adults with a chronic physical health problem see more here. These clearly recommend a stepped care model, whereby milder depression is managed with lower-intensity interventions, and more severe depression by higher-intensity treatments including medication and psychotherapy.



Where does this leave us?
We know that observational studies suggest that a significant minority (in the order of 20%) of brain tumour patients will develop a diagnosable, clinical depressive syndrome at some point in the course of illness. Patients with a past history of depression, and those with significant physical functional and cognitive impairments seem to be at higher risk. Depression is highly correlated with reduced quality of life. The evidence as to whether it impacts adversely on survival is inconsistent.



Clinicians and academics with an interest in this field suggest, broadly, that all patients suspected of having depressive symptoms should receive a formal diagnostic assessment. As a rule of thumb symptoms should be regarded as significant if they are present on most days, for most of the time. Suicidal thoughts appear to be rare in the period following brain tumour diagnosis; if present, these should always be taken seriously and a risk assessment conducted. If depression is thought likely, treatment options should be discussed and a plan agreed. Depending on the level of depression severity, treatment may involve psychoeducation, active monitoring, medication, psychological interventions, collaborative care between neuro-oncology teams and local psychological / psychiatric services, or onward referral for specialist assessment and treatment.