A systematic review and economic model of the effectiveness and ...

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Background
E. Symptoms should not occur exclusively during
the course of a pervasive developmental
disorder, schizophrenia or other psychotic
disorder. Neither should they be better
explained by another mental disorder.
The DSM-IV criteria distinguish between three
subtypes of attention deficit/hyperactivity disorder
according to the predominant symptom pattern
for the previous six months: combined type,
predominantly inattentive type and predominantly
hyperactive–impulsive type.
Choice of diagnostic criteria has important
implications in terms of measuring disease
prevalence and also making treatment decisions.
The ICD-10 criteria are similar to the severe
combined type ADHD defined by the DSM-IV
criteria. Hence, diagnoses based on the former
criteria may be fewer. The two contending
approaches continue to be a matter of
controversial discussion. 15,16
The internal validity of the ICD-10 and DSM-IV
models is also a focus of research and
discussion. 17–24 Studies have been carried out, for
example, to compare the impact of application
across cultures and age groups. Issues of
prevalence, co-morbidity and aetiology, related to
internal validity, are highlighted below.
Co-morbidity and associated features
Considerable overlap exists between hyperkinesis
and other patterns of disruptive behaviour such as
conduct disorder. The ICD-10 diagnostic
guidelines consequently distinguish between
hyperkinetic conduct disorder and simple
disturbance of activity and inattention. 14 The
Items (thousands)
70
60
50
40
30
20
10
0
Mar-99
Sep-99
Items NIC (£)
Mar-00
Sep-00
Mar-01
Sep-01
DSM-IV manual estimates that approximately half
of clinic-referred children with ADHD also have
oppositional defiant disorder (ODD) or conduct
disorder (CD). 2
Common patterns of behaviour and development,
insufficient and unnecessary for diagnosis in
themselves, have also been noted amongst
sufferers:
● disinhibition in social relationships
● recklessness in situations involving some danger
● impulsive flouting of social rules
● cognitive impairment
● specific motor and language developmental
delays
● dissocial behaviour such as temper outbursts.
These associated characteristics often result in
negative interactions with peers, school authorities
and family members and subsequently diminished
self-esteem. 2,14
Current service provision
For the first quarter of 2004, there were 68,000
prescribing items for MPH, at a cost of over £2
million [Figure 1; Prescription Pricing Authority
(PPA) data cover March 1999 to March 2004 in
quarterly periods].
For the first quarter of 2004, there were just under
10,000 prescribing items for DEX, at a cost of just
under £80,000 (Figure 2; PPA data cover March
1999 to March 2004 in quarterly periods). From
December 2001 the cost increased considerably
whereas prescribing remained fairly static. The
Quarter to
FIGURE 1 Trends in prescribing of and spending on methylphenidate in general practice in England and Wales. Source: PPA.
NIC, net ingredient cost.
Mar-02
Sep-02
Mar-03
Sep-03
Mar-04
2500
2000
1500
1000
500
0
NIC (£, thousands)