Medicines are commonly prescribed for people with mental health problems. These comprise the medicines for the mental health problems and, with the greater recognition of associated physical illness, medicines for physical ill-ness.
Medicines for mental illness
Medicines are
commonly prescribed for people with mental health problems. These comprise the
medicines for the mental health problems and, with the greater recognition of
associated physical illness, medicines for physical ill-ness. For those with
severe mental health problems most will be prescribed mental health medicines
for extended periods of time. This long-term, possi-bly lifelong, need means
extended periods under the care of mental health professionals alone, jointly
with shared care with a general practitioner (GP) or as discharged solely to
the care of a GP. Many mental health medicines take weeks, if not months, to
achieve a satisfactory response, although the short-term sedative effects may
prove sufficient to allow early discharge of a still largely unwell person back
into the community.
Most mental health
medicines are associated with an array of side-effects that many patients find
unpleasant and possibly unacceptable. In addition, many have only partial
effectiveness or are only effective against some aspects of the illness. These
factors make choice of medicine a key issue for pharma-cists and psychiatrists,
with frequent trials of alternatives. This adds to the difficulty in
determining the usefulness of the medicines, as assessments are often based on
subjective responses and subject to a large number of variables.
The pivotal
discoveries in the late 1940s and 1950s that changed mental health medicines were
those of the phenothiazine antipsychotics, the tricyclic and monoamine oxidase
inhibitor antidepressants and lithium for bipolar illness. Following shortly
after was the arrival of the benzodiazepines both as sedatives and hypnotics.
For the first time there was an array of medicines truly effective in managing
psychosis, mania and depression.
The discovery of
chlorpromazine is regarded as the key event that led to the fall in population
of the asylums (then almost 150 000) but others claim that the decline had
started earlier, following the changes to the 1959 Mental Health Act. Whichever
explanation, the arrival in the 1970s of the long-acting formulations of
antipsychotic drugs showed the development of community psychiatry was well
under way.
Throughout the 1970s
and 1980s there were few novel medicines in mental health, with most
introductions being chemical variations or new formulations of those already
available. Many were attempts to reduce the side-effects of the original drugs,
make them work quicker or enhance their efficacy. However, the movement
disorders (called extrapyramidal side-effects) associated with the
antipsychotics and the toxicity of lithium and the antidepressants remained
sources of concern. The 1990s saw another wave of developments as research into
the mode of action of clozapine caused a change of attention of antipsychotic
drug research to the mesolimbic system in the brain and to different receptors.
Clozapine does not chronically alter striatal D2 receptors but does
appear to affect them. It also appears to have more effect on the limbic system
and on serotonin (5HT2) receptors, which may explain its reduced
risk of extrapyramidal symptoms. The term ‘atypical’ is used to categorise
those antipsychotic drugs that, like clozapine, rarely produce extrapyramidal
side-effects.
Although the reason
for the superiority of clozapine in schizophrenia treatment remains an enigma,
a variety of theories have led to the develop-ment of a new family of
antipsychotic drugs. Some mimic the impact of clozapine on a wide range of
dopamine and serotonin receptors, for example olanzapine; others mimic the
impact on particular receptors, for example 5HT2/D2
receptor antagonists such as risperidone; others focus on limited occupancy of
D2 receptors, for example quetiapine; while others focus on
alternative theories such as partial agonism, for example aripiprazole.
The other revolution
to occur in the 1990s was fluoxetine. Although not the first selective
serotonin reuptake inhibitor, this antidepressant became the medicine for the
masses in the 1990s and rivalled the 1960s’ use of the benzodiazepine diazepam
in popularity. Throughout the 1990s and 2000s mental health practice saw a wide
range of new medicines introduced for bipolar (antiepileptic drugs and
antipsychotics), attention deficit hyperactiv-ity disorder (wider use of
methylphenidate), Alzheimer’s disease (cholinester-ase inhibitors),
schizophrenia (atypical antipsychotics) and depression (noradrenaline
(norepinephrine) and serotonin reuptake inhibitors)
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