P s y ch o lo g ica l, social and o c c u p a tio n a l fu n ctio n in g can be affected by alcohol abuse of either long or short duration and can result in problems with em otional and cognitive function, family, work and the legal system. T hese p ro b lem s are m ore p re v a le n t than alcohol d e p en d e n ce , but the concepts are not mutually exclusive (ie 15-35%, cited in Leigh & Skinner). B iom edical conditions have ran g ed from traum a w hile intoxicated to the physiological com plications of reg u lar use (eg. liver disease, pancreatitis, hypertension, gastritis, brain d am ag e, etc).
A l c o h o l P r o b l e m S c r e e n i n g A c c u r a c y
In order to describe the accuracy of alcohol problem m easurem ent for a prescribed sam ple and the particular m ethod of assessm ent, two concepts are freq u en tly reported in the e p id e m io lo g ic al literature (O 'D o n n ell, De Soto & Reynolds 1984):
Test Sensitivity
This is the ability of a screening test to correctly classify genuine cases of alcohol m isuse as abnormal. It is usually represented as the percentage of actual excessive drinkers w ho obtained an abnorm al score. Incorrect classifications are called false negatives.
Test Specificity
This is the ability of the same test to correctly classify genuine cases of safe drin k in g as normal. It is usually rep resen ted as the p ercen tag e of n o n - e x c e s s i v e d r in k e r s w ho o b t a i n e d a n o r m a l s c o r e . I n c o r r e c t classifications are referred to as false positives.
The aim of any screening assessm en t technique w ould be to m axim ise both co n cep ts with the ideal m easuring devise having 100% sensitivity and 100% sp e cificity for c o rre c tly c la s s ify in g c ase s. In p ra c tic e the proportions are often much less than this, but the tests still have their uses. T h ese co n cep ts are sim ila r to the m ore so p h is tic a te d c riterio n - related valid ity of psychom etric assessm ent, w here T ype I and Type II erro rs u s u a lly d e scrib e d ia g n o s tic a c c u ra c y ( O 'D o n n e ll et al 1984). Problem s arise when the co m p arab ility of these concepts across studies have b een c o m p ro m is e d by a m b ig u ity in d e fin itio n o f the criterio n d rin k in g c ateg o ries.
S e l f R e p o r t e d D r i n k i n g P a t t e r n
Despite the popular perception that individuals under-report their alcohol c o n s u m p t i o n , the p r o ce d ur e has be en f o u n d to be fairly accu rate provided a context for cooperation has been es tablished (Maisto, Sobell, Cooper & Sobell 1979; Leigh & Skinner 1988; Vuchinich, Tucker & Harllee 1988). This includes being aware of factors other than motivation that promote in accuracy (eg. intoxication, n e u r o p s y c h o l o g i c a l imp ai rm en t of m em o ry and c o n c e n tr a tio n, an xie ty and d e p r e s s i o n ) . The severity of thes e p r o b l e m s can ab ate in the w e e k s f o l l o w i n g d e t o x i f i c a t i o n , improving the accuracy of subsequent self reports (Vuchinich et al 1988). Studies of A RB D comparing patients from a lc o h o li sm treatment centres against social drinking controls have been c rit ici se d for assuming the latter were free of alcohol problems. Moreover, patients from treatment centres can be surre pti tio us ly d if f e r e n t fr o m c o n tr o l s on motivation, psychological distress, premorbid brain dama ge, family history, education or medical complications. This can produce spurious differences between the groups and may account for equivocal findings throughout the ARBD literature (Parsons 1986; Grant 1987; Parsons, Butters & Nathan 1987). Thus, self reports of recent or lifetime consumption may help to avoid the m e t h o do lo gi c al prob lems a sso ci ate d with using st e r eo ty pe d alcoholics. Kra nzle r, B ab or and L a u e r m a n (199 0) f o u n d d a il y c o n s u m p ti o n and frequency of intoxication were related to adverse physical, psychological and social c o ns eq u e n ce s of alcohol abuse am o n g m edical, dental and alc oh ol r e h a b i l i t a t i o n p ati en ts. T h ey f o u n d p a t t e r n s of c o n s u m p ti o n inter act ed in a c o m pl ex m an n e r with g en der , age, nu tr itional status, ge netic p r e d i s p o s i t i o n and c h o ic e o f b e v e r a g e . T h e i r n o n - al c o h o lic s di ffered from alcoholics on m o st p r o b l e m i n d ic a t o r s while the latter group va rie d a m o n g th e m se lv e s on p h y s i c a l sign s and se verity of d e p e n d e n c e .
In re c e n t re v ie w s of the lite ra tu re, c o n s u m p tio n v a ria b le s have had mixed success in dem onstrating a relationship betw een alcohol abuse and brain im pairm ent (Parsons 1986; Grant 1987). D isagreem ent about what c o n s titu te s s o c ial, m o d e ra te , h e av y , at r is k , h a z a rd o u s or harm fu l d rin k in g m ay be p a rtly re s p o n s ib le (N H & M R C 1991; G rant 1987). M oreover, different terms have been used to describe similar or identical drin k in g p attern s (eg. spree, binge, bout, d aily , reg u la r, and steady), illustrating the need to standardize terms and concepts (NH &M RC 1991).
Classification of Alco hol Problems
The A m erican Psychiatric A ssociation (1987, p l 7 3 ) produced a multiaxial diagnostic classification system for alcohol misuse disorders based on two distinct clusters of alcohol problem s or syndrom es; alcohol dependence
a n d alcohol abuse. Although the system allow ed for multiple diagnoses, such as in to x ic a tio n , u n c o m p lic a te d w ith d r a w a l, d e lir iu m , am n e stic syndrom e, or other m ental d iso rd er, diagnostic am b ig u ity in identifying tolerance and w ithdraw al sym ptom s over other alcohol related behaviour has made it difficult to reliably classify alcohol p roblem s according this system (Butters, Parsons and Nathan 1987). Butters et al suggested that alco h o l re la te d n e u ro p s y c h o lo g ic a l c h a n g e s w ere m ore likely to be a s s o c ia te d w ith a lc o h o l d e p e n d e n c e than a lc o h o l ab u se alo n e, so characteristic differences in NP perform ance could help differentiate the two disorders and their severity. Tarter, Arria, M oss, Edw ards and Van Thiel (1987) questioned the specificity and construct validity of the DSM- III taxonomic system for the diagnosis of alcoholism . Despite a revision, th ey c o n s i d e r e d the s y s te m to be o v e r i n c l u s i v e and c lin ic a lly uninform ative. T hey suggested, "the m easurement instrum ent employed will determine largely the prevalence and characteristics o f individuals deemed to be alcoholic" (p543). Thus, the system m ay add little more to our u n derstanding of alcohol problem s than Je llin ek 's five categories of alcoholism and the term d e p e n d e n t could easily becom e a synonym for
alcoholic. Individual m anifestation of alcohol problem s should alw ays be seen as a unique in te rac tio n betw een p s y c h o -b io lo g ic a l p ro c e s s e s of d e p e n d e n c e and the s o c io -c u ltu ra l e n v ir o n m e n t (C la rk e & S a u n d e rs
1 9 8 8 ).
P s y c h o m e t r i c A s s e s s m e n t
Pu r p o s e
V a r io u s p s y c h o m e tr ic sc ale s h av e been d e s i g n e d to m e a s u r e the m u ltid im e n sio n al nature of a lco h o l p ro b lem s and d iffe re n tia te betw een n o rm al and p roblem d rin k ers. M ost have b een se lf r e p o r t sch ed u les d e s ig n e d for risk sc ree n in g , r e s e a rc h s e le c tio n , d ia g n o s is , tre a tm e n t planning or outcom e evaluation (D avidson 1987). They are e ith er based on the M M P I p e rs o n a lity in v e n to r y or a lc o h o l r e l a te d p h y s ic a l, psychological and social disabilities (eg. ALCADD, CAGE, M AST, SM AST & C A ST). Som etim es they have form ed part of general health screening tests or have been com bined w ith laboratory and p h y sical e x am in atio n s (Clarke & Saunders 1988; M ALT- Feuerlein, Ringer, K ufer & A tons 1980, cited in Elvy 1985; A C I-Skinner & H olt 1987). U n fo rtu n ately , m any of these scales were designed to detect al coholism. As a result, they lack a s o u n d t h e o r e t i c a l f r a m e w o r k , h a v e q u e s t i o n a b l e s t a t i s t i c a l or psychom etric properties and are often used on p o p u latio n s for purposes other than that for which they were designed (Elvy 1985). In contrast, scales which have been based on the construct of the Alcohol D ependence Syndrome (eg. ADS, SADD, SADQ, ADD, HDBQ & EADS) have avoided any inherent association with Jellinek's dubious disease m odel.
A lco hol De pen de nce Syndrome
Edwards & Gross (1976, cited in Butters, Parsons & Nathan 1987; Clarke & Saunders 1988, p38) proposed the "Alcohol D e p e n d e n c e S y n d r o m e " (ADS) as a u n i - d im e n s i o n a l c o n s t r u c t in v o lv in g an i n t e r a c t i o n b e tw e e n biological, psychological, socio-cultural and excessive drinking factors. The
process of de p en d e nc e is r e p r e s e n t e d by a m e a su r a b le c o n ti n u u m of severity with excessive drinking at one end and severe dependence at the other. At the severe end, signs and symptoms of alcohol problems are likely to be more numerous, have been e n d u re d for longer and are usually m or e fu nc ti o n al ly d e b il i ta ti n g . Scales d e v e l o p e d from this c o n c e p tu a li s a t io n have been f act or a n a l y s e d and f o un d to have first factors that account for most of the variance in scores. Since a uni dimensional factor should explain the majority of individual differences on ADS tests, its discovery for individual tests may help to establish their construct validity (Elvy 1985). The concurrent validity of ADS scales has been d e m o n s t r a t e d by c o r r e l a t io n s with o th er alc oh ol p r ob le m s and scales ( D a v id s o n & R ais tri ck 1986). But ter s et al (1987, p399) considered the term alcoholic referred to patients at the severe end of the d e p e n d e n c e c o n t i n u u m . T h e y s u g g e s t e d t h a t " c o n s t e l l a t i o n s o f n e u r o p s y c h o l o g i c a l d ys f u n ct io n a s s o c i a t e d with a b u si v e dri n k in g " may c oi nc id e with points along the d e p e n d e n c e c o n t i n u u m wh ic h would support the validity of the ADS construct and enable greater precision in the cli ni cal as se ss m e n t of e x c e s s i v e drin ker s. H o w ev e r , only low correlations have been found between NP p e rfo rm anc e and ADS scales, which can be due to the confounding influence of other factors (Skinner and Allen 1982). The relationship of ADS scales with liver function and ha ematology status have also been inconclusive. However, patients with a lc o h o l r e l a t e d liver d i s e a s e an d s u b s e q u e n t l y e l e v a t e d l a b o r a to r y m e a s u r e s may e x p e r i e n c e fe w w i t h d r a w a l s y m p t o m s or m ay have stopped drinking since hospitalisation. As ADS scales contain numerous items w hi c h assess r e c e n t e x p e r i e n c e of a l c o h o l w i t h d r a w a l , these patients may be only mildly dependent at the time of testing (Davidson & Raistrick 1986 citing Wodak, Saunders, Ew usi-Me nsah, Davis & Williams
1 9 8 3 ) .