Dr Hugh
Rickards, consultant in neuropsychiatry, Queen Elizabeth Psychiatric Hospital,
Birmingham
Way Ahead
2003;7(1):6-7
“The
mind is what the brain does” – Prof. Steven Pinker: How the mind works.
MS is primarily
a disease of the brain. As this is where mental functions are controlled, it
isn’t surprising that changes in mental status are common in people with MS
(PWMS).
However, mental
disorders in MS are frequently overlooked for a number of reasons:
- Changes
in mental state are considered to be solely a ‘reaction’ to having a
chronic illness - Many
mental health services have retracted so they only treat ‘functional’
mental illnesses - The
relatively few neurologists in the UK often restrict themselves to
diagnostic issues and managing physical symptoms - Understanding
symptoms of mental disorder is a complex process, often touching on
personal and family issues. It can be easier to stick to the physical and
practical aspects of care.
The burden of
responsibility for mental illness in MS usually falls on relatives, carers and
MS specialist nurses, who don’t always feel adequately skilled to advise. This
burden is heavy and may contribute to reduced quality of life in MS.
Practitioners
need a number of skills to manage mental disorder in MS, including knowing how
MS affects the brain, understanding the effects of prescribed and
non-prescribed drugs on mental function and being able to recognise major
mental disorders, such as depression, psychosis and cognitive impairment.
Additional skills include understanding psychodynamic theory and “family
systems” theory.
Depression in MS
Depression is a
very common mental illness in MS. Around half of all PWMS will have clinical
depression at some time, around three times the incidence in the general
population. Depression in MS can sometimes be difficult to diagnose as many
symptoms, such as fatigue, weight loss and lethargy, may occur in both
conditions. Important clues in the diagnosis of depression include: pervasive
low mood, sometimes with diurnal variation – often the mood is particularly bad
in the morning; reduction in physical function that is disproportionate to
their level of physical disability – level of physical disability does not
correlate well with the risk of getting depression; and suicidal ideation.
Suicidal ideas are quite common in PWMS who attend clinics, occurring in 25% at
any one time. One study showed around 3% of PWMS will take their own lives,
especially socially isolated young men with MS.
Transient low
mood is normal in the period immediately after diagnosis and is known as
adjustment disorder. Various common medications in MS, such as steroids,
baclofen, dantrolene and interferon can cause changes in mood in either
direction. Physical conditions, such as anaemia, vitamin deficiencies and
thyroid disease can present with depression and need to be excluded.
Treating
depression in MS is often rewarding and drugs in the Specific Serotonin
Reuptake Inhibitor (SSRI) group are probably safest. Common side effects, usually
transient, include nausea, sexual dysfunction and gastrointestinal disturbance.
Withdrawal from these drugs should be gradual, especially with paroxetine
(Seroxat).
Mania is
relatively rare and, where it occurs, one should consider whether prescribed or
non-prescribed drugs have been the trigger.
Paroxysmal emotional states
Paroxysmal
emotional states are transient changes in behaviour or emotion, which resolve
quickly. These are divided into pathological laughing and crying and emotional
lability.
Pathological
laughing and crying can occur in up to 10% of PWMS. The response can be to
random stimuli and not related to how the person is feeling. Such laughing or
crying may be short-lived (lasting only a few seconds) and is particularly seen
in people with chronic MS with cognitive impairment. Pathological crying can be
mistaken for depression but the mood is usually not pervasively low. Where it
causes distress or disability treatment may be with amitryptilline, l-dopa or
amantadine.
Emotional
lability is characterised by an excessive emotional response to a minor
stimulus, eg excessive emotional responses to soap operas on TV. Again the
response is transient and has been described as ‘an April shower’. Effective
treatment has been described with carbamazepine and SSRIs.
Psychosis in MS
Psychotic
symptoms – delusions, hallucinations and thought disorder – are uncommon in MS
but extremely distressing. This may result in family breakdown and nursing home
placement. Symptoms are similar to those seen in ‘functional’ psychoses such as
schizophrenia, although visual hallucinations are more prominent and the mean
age of onset (36 years) is later.
If a PWMS
becomes psychotic (especially if there is acute onset) it is important to rule
out physical triggers such as chest and urinary tract infections and metabolic
disturbances. Steroids, baclofen and dantrolene have all been reported to
trigger psychosis in people with MS so a close review of the treatment history
is vital. People with severe depression may develop psychotic symptoms
congruent with their mood – for instance delusions of poverty or guilt – and
here treatment should be aimed at the depression. Finally, psychotic symptoms
in MS may be the presenting feature of dementia.
People with MS
are particularly sensitive to neuroleptic (anti-psychotic) medications.
Rigidity and bradykinesia are commonly encountered even at low doses of
conventional neuroleptics such as haloperidol. Therefore, atypical
antipsychotics (quetiapine or olanzapine) should be first line therapy in this
situation. The few studies about the prognosis of psychosis in MS suggest that
treatment response is fair.
Cognitive changes
Many PWMS
experience significant changes in cognitive function over time. Around 40% of
PWMS in the community have some cognitive impairment. Typical problems include
reduced speed of processing, reduced attention span and problems with executive
function. Such problems may be the source of considerable disability but may
not register on standard tests, such as the Folstein Mini Mental Status
Examination or MMSE, or at clinical interview as verbal skills may be
unaffected. Occupational therapy assessment at home is one of the best ways of
detecting impairments in executive function. Specific tests that can reveal
executive dysfunction include the Addenbrookes Cognitive Examination (ACE), the
Frontal Assessment Battery (a short, sensitive, ‘bedside’ test) and the
Behavioural Assessment of Dysexecutive Syndrome (BADS).
Conclusion
Mental status
changes are extremely common in MS and are relatively neglected. They need
thorough assessment with particular attention given to mood changes, cognition
and perception. Many treatment or management strategies are effective.
There is a real
danger that people with MS and mental illness will be excluded from services
and it is vital that health professionals in neurology, psychiatry and
rehabilitation work together to prevent this.
.