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CAUSATION IN CLINICAL PRACTICE It is usual in everyday psychiatry to have multiple causes acting together to produce an episode of illness- so-called multifactorial causation.
The accepted way of considering these subsidiary causes in psychiatry is in terms of various
- predisposing (see below under "vulnerability")
- precipitating and
- perpetuating factors.
CASE ILLUSTRATION For example, a person with a depressive illness may have been predisposed to develop it through an anxious personality, the illness being precipitated by relationship breakdown and perpetuated though alcohol misuse and inactivity.
CAUSATION IN MEDICOLEGAL PRACTICE The same approach should be applied in medicolegal reports. However, it is easy to overemphasise the precipitating factor (e.g. accident), and the report will lack credibility if predisposing (e.g. previous episodes) and perpetuating factors are ignored.
COMMON PERPETUATING FACTORS in respect of psychiatric illness post-trauma include
- pain and other effects arising from physical injuries and disabilities
- financial and other losses as a result of inability to work
- substance misuse, especially a common but misguided tendency to self-medicate for pain and distress with alcohol.
It is also undeniable that the legal process itself is worrying for patients (so-called "litigation stress"), not least as it is protracted and they feel out of control.
CAUSATION: PROPORTIONALITY Often, in medicolegal work, there is a presumptive cause (e.g. a road traffic accident) and the diagnosis will be fairly clear. It should be possible to link these together in fairly straightforward terms if the accident and the illness are plausible and in proportion.
CAUSATION: LACK OF PROPORTIONALITY However, if an apparently trivial accident is followed by a very severe illness, for example if a person trips over a paving slab and then describes total and permanent disability, the link is harder to make. It may then be that the difficulties described by the patient cannot be explained in medical terms.
VULNERABILITY The issue of vulnerability may then arise (the ěeggshell skullî argument), where a person can genuinely develop a severe condition after a minor trauma if he is predisposed to do so by some pre-existing weakness or vulnerability in his personality.
In order to demonstrate such vulnerability, it is necessary to consider how the person has coped with previous adverse experiences in life. If a person was vulnerable, one would generally be expecting some evidence, for example from the medical records, that previous shocks had been followed by some form of significant and disabling emotional distress.
If, on the other hand, the person appears to have coped previously with resilience, it becomes more difficult to establish vulnerability in respect of the index accident.
In these circumstances, a ělast straw that broke the camelís backî argument is sometimes advanced: the patient kept going in spite of a number of repeated adverse events. These, it is argued, had the effect of building up his vulnerability, so that the minor event in question was responsible for the subsequent mental health problems.
Sometimes there is a crucial qualitative difference between the previous events and the index event, in that the former were non-compensatable and the latter is; if so, this may throw doubt on it. On other occasions, there can seemed to be more substance to this line of reasoning.
VULNERABILITY: HOW DOES IT ARISE? A patient can be vulnerable or predisposed to develop mental health problems, following an adverse event, in a number of interrelated ways as follows:
- Genetic factors are important in the causation of many if not most psychiatric conditions. This applies particularly to the more severe psychiatric conditions, for example, psychotic disorders such as schizophrenia, and bipolar affective disorder.
So that, if someone with a strong family history of say, bipolar affective disorder, developed bipolar affective disorder after a minor accident, then it would probably be unreasonable to blame the accident, for the development of the bipolar affective disorder.
It might be more reasonable to argue that the person would have developed bipolar affective disorder in any case. It would follow that the accident might have brought forward the onset of the bipolar affective disorder, but there it would not be reasonable to blame the accident for the bipolar affective disorder in the main.
- Childhood experiences. In spite of two generations of retreat from the ideal of the "nuclear family", clinical experience leaves little room for doubt about the conservatism of children in regards to the family environment they prefer.
Young children are affected, even when it is a matter of parents splitting up in a "civilised manner". it must come as no surprise therefore that if they are exposed to physical or emotional or sexual abuse, or even to instability and lack of love, this can frequently have long-term adverse consequences to the developing personality.
This may lead to long-term tendencies towards low self-esteem, depression, anxiety and related symptoms, and these might especially apply to females. In males, conduct disorder, and antisocial behaviour , would be more usual.
The individual would have a higher risk than average of going on to develop personality disorder, substance misuse, and depression and anxiety.
Hence, the argument might be that a person with symptoms after an accident, who had such a background, would have developed the problems anyway, even if the accident had not happened.
On the other hand, the eggshell skull principle would argue that the pre-accident personality, adverse childhood experiences and all, was the appropriate legal baseline.
- Personality from the clinical point of view, it is clear that the individual's personality is one of the most important factors in how they cope with an adverse event such as an accident.
Difficulty in coping with everyday life, for example, with school, work, personal relationships, and outside interests, would obviously indicate that the person under evaluation might have long-term difficulties, possibly even to attract a diagnosis of a personality disorder.
- Coping styles are a further significant factor to be evaluated. A person who has an "internal locus of control", that is, who regards life problems as something he himself can sort out, will probably do better overall than a person with the opposite attribute. "External locus of control" implies that the person blames other people or the outside world for their difficulties; the sense of "self-efficacy" is therefore less, and the person concerned, tends to do worse from the clinical psychiatric point of view.
- Lack of support The classic work of Brown and Harris, amongst many others, has demonstrated that good support networks help people to cope with adverse events. Poor support- lack of family and friends- makes it harder to cope with adverse events, which are therefore more likely to lead on to psychiatric illness.
- Previous psychiatric history If the patient has had a previous episode of mental ill health, of whatever kind, they are more likely than the average person to have further such episodes in the future.
The effect varies greatly from individual to individual.
If the patient has had a mild episode, many years ago, which appeared to come on in relation to an external shock and which cleared up completely, then it might have little or no relevance to the causation of a further episode under current consideration.
If, on the other hand, the patient has had many severe episodes of mental illness, long-lasting, or even with continuous (chronic), symptoms, then the previous psychiatric history is obviously of fundamental importance in considering the possible psychiatric consequences of an accident or other adverse event. In these circumstances, one may usefully consider the possibility that an accident has brought forward in time a further episode of illness, which would inevitably have occurred anyway.
CAUSATION: THE INDEX EVENT Last but not least, some consideration of the index event is required. I have put this section at the end of my chapter on causation deliberately, this report writers tend naturally to overemphasise the index event, at the expense of predisposing and perpetuating factors.
Obviously, the psychiatrist is not an expert on accidents per se. However, some account of it is necessary. It is possible to get some common sense appreciation of whether it was a mild affair, for example, a rear end shunt road traffic accident, which must be so common as to be regarded as almost a normal part of human experience. Or whether, on the other hand, it was a more severe and out of the ordinary experience, such as a life-threatening assault or a severe road traffic accident.
FURTHER DISCUSSION OF TRAUMATIC EVENTS AND CAUSATION of psychiatric disorder will be found in my chapters on PTSD and stress at work.
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