Electrical aversion therapy with alcoholics: An analogue study

Chronic alcoholic patients matched on age, education and length of problem drinking were assigned to one of three treatment conditions, with 10 subjects in each group: (1) Electrical Aversion Conditioning (high shock paired with alcohol sips); (2) Control Conditioning (very low shock paired with alcohol sips); and (3) Group Therapy (confrontation psychotherapy). Groups 2 and 3 were included to control for possible ‘attention-placebo’ and expectancy factors involved in the conditioning procedures. Subjects in each group were given instructions designed to produce high expectancy for therapeutic success. Pre-post measures of alcohol consumption and attitudes toward alcohol were obtained using an analogue ‘taste test’ assessment procedure. No statistically significant differences in reduced alcohol consumption or attitudes toward alcohol were found among the groups. Trends in the data support the contention that effects of electrical aversion may be more related to such factors as therapeutic instructions, expectancy, specificity of the procedure or experimental demand characteristics than to conditioning factors.     

The treatment of addiction by aversion conditioning with apomorphine

An account is given of the techniques employed in using apomorphine for the treatment of chronic alcoholism, addiction to other drugs and addiction to cigarette smoking. No evaluation is made here but each technique is illustrated by the report of a case in which the result is considered, after a reasonable follow-up period, to be highly satisfactory.     

Taste aversion learning: simulation of interference with the gustatory cue during conditioning

Rats were taught an aversion to a sucrose taste cue of varying strengths. The concentration of the sucrose solution was either, 10, 7.5, 5, 2.5, 1, 0.5, or 0.25% which the animals drank for 5 min. Thirty minutes later they were poisoned with lithium chloride. On the test day all animals had access to a 10% sucrose solution regardless of the concentration they had drunk on the conditioning day. Animals conditioned with a 10, 7.5, or 5% sucrose cue subsequently displayed an identically strong aversion to the 10% cue. Only those animals conditioned with a sucrose cue which was 1% or less displayed a significantly weaker aversion to the 10% cue. The results are discussed in terms of the theory that interference with taste aversion learning by such agents as pentylenetetrazol and electroconvulsive shock may have their effect by disrupting the gustatory engram. If this assumption is correct then it suggests that the memory of the gustatory cue may be stored, at least prior to poisoning, in a quite labile state and an apparently limited disruption of taste aversion learning may in fact represent a substantial amnesic effect.     

Salience and the effects of CS preexposure on aversion conditioning

Rats (n = 84) received preexposure to distilled water or to one of two differently salient flavors, 5.0% casein or 10.0% sucrose, casein being the more salient. Each preexposure group then received aversion conditioning to a 5.0% casein or a 10.0% sucrose CS. Aversion effects were reliably more enduring to casein than to sucrose. Relative to water-preexposed groups, preexposure to casein attenuated aversion effects to the casein CS reliably less than preexposure to sucrose attenuated aversion effects to the sucrose CS. During preexposure, neophobia was reliably greater to casein than to sucrose, suggesting that the demonstration of salience in taste aversion learning may be based on the inherent aversive properties of novelty.     

Chemical aversion conditioning in the treatment of alcoholism: further comments.

The literature on consummatory aversion (CA) conditioning in rats does provide a well-developed theoretical foundation for chemical aversion conditioning. Nevertheless, differences between rats and humans in CA learning suggest caution in extrapolating from the animal laboratory to the treatment of alcoholic patients. Serious methodological problems with studies of emetic therapy with alcoholics preclude unambiguous evaluation of its effects. Emetic therapy is an intrusive and relatively costly form of treatment which has not been shown to be more effective than alternative, less costly methods. The onus is on proponents of this method to demonstrate its specific advantages over alternative treatments.     

Higher-order conditioning and sensory preconditioning of a taste aversion with an exteroceptive CS1

An exteroceptive stimulus compound (context) was employed as CS₁ in higherorder conditioning (H-OC, Experiments I and II), and sensory preconditioning (SPC, Experiment III) of a saccharin (CS₂) aversion in rats. The results indicated that aversions were established with the H-OC as well as with the SPC procedures. Stimulus generalization and first-order conditioning explanations were ruled out by appropriate controls. A CS₁-extinction period, performed prior to testing, did not affect the H-OC aversion, whereas it reduced the SPC aversion at least partially. These findings imply that interoceptive (taste, nausea) and exteroceptive stimuli (context) are readily associable in rats. Implications of the resemblance between the SPC procedure and long-delay taste-aversion learning are discussed.     

Relative potency of foods and drinks as targets in aversion conditioning

The potency of food stimuli as targets in aversion learning was examined using an interference paradigm. In the first study, foods interfered with liquid aversions but liquids did not interfere with food aversions. In the second study, food aversions were found to be resistant to interference by other foods. These findings suggest that foods are relatively potent targets in aversion conditioning in that they are resistant to interference by both foods and drinks. The final study examined the contribution of flavor intensity and nutrient density to the potency of aversion conditioning. The relative potency of foods over drinks may reflect differences in their intensity as well as their different roles in toxin avoidance and nutrient selection.     

The role of cue additivity in salience in taste aversion conditioning

In toxiphobia conditioning certain cues are more easily associated with malaise (i.e., more salient) than others. The present experiments show that cue additivity can account for previously found differences in salience of certain fluids. The relative salience of saccharin, saline and casein hydrolysate was tested in normal rats and in animals rendered anosmic by treatment of their nasal passages with zinc sulphate. The normally more salient casein was reduced in salience to the same level as saccharin and saline in the anosmic animals, while anosmia did not affect the relative salience of saccharin and saline. A second study tested the cue properties of vanilla, a fluid of very low salience. Anosmic animals could not show a conditioned aversion to vanilla. Normal animals readily learned the aversion but could not show it following a later anosmia treatment. Anosmia did not disrupt a saccharin aversion previously conditioned in normal animals. The data show that some of the “tastes” used in toxiphobia conditioning have olfactory components, and some are purely olfactory. Further, olfactory cues can summate with taste cues to form a more salient stimulus.     

Ontogenetic differences in conditioning of an aversion to a gustatory CS with a peripheral US

Rats 5, 10, or 15 days postnatal were given six pairings of an infused sucrose solution and footshock. Conditioned aversion to the sucrose solution was confirmed for the 5- and 10-day-old pups, but no conditioning was evident for the 15-day-old pups (Experiments 1 and 1A). In Experiment 2 the ventral portion of the rat's body was insulated from the shock source in order to isolate its effect on the feet and minimize visceral consequences of the shock. The sucrose-shock conditioning occurred as before. These results may have implications for the postnatal development of cue-consequence specificity, suggesting that such specificity may in part be learned. The present results also raise the possibility that sources of discomfort may be relatively undifferentiated in the perinatal rat.     

Overshadowing of a context aversion by a novel incentive in operant conditioning

Two experiments examined the processes underlying the suppression of instrumental behaviours by lithium in rats, as reported by Meachum (1988 and this issue). Experiment 1 examined whether presenting a novel sucrose solution prior to lithium chloride administration would overshadow aversion learning to either the stimuli of the operant chamber or to familiar food pellets. After lever pressing had been established, and in the absence of responding, animals received free deliveries of a novel sucrose solution, familiar food pellets, or both, or they were exposed to only the cues of the operant chamber, prior to lithium injections. Lever pressing for food pellets was then assessed. It was found that the animals receiving the novel sucrose, either alone or with the familiar food pellets, pressed more for pellets than either the group receiving only food pellets or the group exposed to only the context. In addition, there was no appreciable difference in the response rates between the context-only group and the group that received the familiar food pellets. These outcomes were interpreted in terms of the novel sucrose overshadowing aversion learning to the context. Experiment 2 investigated whether in fact aversive contextual conditioning could be obtained using the present parameters. This was accomplished by directly manipulating the contexts. In this experiment animals were trained to lever press in two distinctive contexts. Subsequently, one context was paired with the novel sucrose, and the second was experienced in the absence of reinforcement prior to toxicosis. During a subsequent non-reinforced test it was found that responding in the context paired with the novel sucrose was considerably higher than responding in the context that was experienced alone. These findings stand in contrast to the taste-mediated contextual potentiation observed when a consumatory response is used to assess aversive contextual conditioning.     

Pavlovian conditioning with ethanol and lithium: effects on heart rate and taste aversion in rats

Rats received paired injections of either ethanol or saline as the conditioned stimulus and lithium chloride as the unconditioned stimulus (US) in a Pavlovian differential conditioning paradigm. Lithium chloride evoked a large deceleration in heart rate (80-100 beats per minute) as an unconditioned response. As a result of 10 conditioning trials, the substance paired with LiCl elicited a lower average heart rate than that elicited by the unpaired substance. Moreover, animals that received ethanol-LiCl injections subsequently were more averse to the taste of ethanol than animals receiving saline-LiCl pairings. However, there were no differences in ethanol's ability to serve as the US to induce an aversion to a novel flavor solution (i.e., the Avfail phenomenon was not observed). The overall pattern of results underscores the value of using multiple indexes of learning in drug-drug conditioning paradigms.     

Effects of flavor salience on aversion performance following relatively long-delay backward conditioning procedures

Male albino rats (n = 144) received a 0.15 M injection of lithium chloride (at 2.0% body wt), followed 10, 30, or 75 min later by a 5.0% casein CS or a 10.0% sucrose CS, casein being the more salient CS. For each CS one-third of the rats received no fluid during the toxin-CS interval. The remaining two-thirds of the rats received 2-min access to distilled water or to a novel flavor 5 min after onset of the toxin-CS interval. For sucrose CS groups, the novel flavor was casein; for casein CS groups, the novel flavor was sucrose. Groups which received no fluid during the toxin-CS interval showed reliably greater aversion effects to the casein CS than to the sucrose CS. Results of Test Trial 1 showed that aversion to casein was relatively unchanged across toxin-CS intervals, while aversion to sucrose decreased reliably from the 10-min to the 30- and 75-min intervals. However, for each toxin-CS interval, aversion to the sucrose CS was reliably enhanced when casein access occurred in the interval, relative to that for distilled water or no fluid access. For the casein CS, access to sucrose or distilled water in the toxin-CS interval altered aversion effects, relative to the no fluid condition, depending on the interval.     

An experimental analysis of aversive imagery versus electrical aversive conditioning in the treatment of chronic alcoholics

A series of three experiments is described comparing an aversive imagery and an electrical escape conditioning procedure in the treatment of chronic alcoholics. Treatment effects were objectively measured by recording subjects' alcohol consumption in a semi-naturalistic laboratory setting. In contrast to conventional group outcome studies, the use of single-subject methodology provided a fine-grained analysis of individual response patterns. The aversive imagery and escape conditioning methods did not differ from each other, and were relatively ineffective in suppressing alcohol intake. In contrast, a punishment procedure in which shock was contingent on drinking did effectively suppress drinking. The data suggest that alcoholics can control their drinking by self-administered shock. The implications for the analysis and treatment of alcoholics are discussed.