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Detecting acute drug effects
BIOLPSYCHIATRY 1989:25:645-w
645
Detecting Acute Drug Effects Karley Y. Little
Introduction Both the Profile of Mood States (POMS) and Visual Analogue Scales (VAS or 100~mm line tests) have been used to detect acute drug effects in humans. Recently, there has been increased use of VAS alone because of easily perceived advantages, such as being nontiring, easy to score, and replicable without carryover cuing, as well as having face validity. Compared to the POMS, it is unclear if VAS are more sensitive and straightforward or are less reliable and susceptible to lapses in concentration or impulsivity. VAS are clearly less validated, as no standardized forms exist and users typically label extremes with their own construct. In this experiment, we compared POMS and VAS results to observer’s ratings after subjects ingested stimulants.
chogenetics Behavioral Rating Scale (PBRS) 30 min before ingesting the capsules, then 90 and 150 min later.
Instruments The POMS six mood factors-anger,
depression, tension, confusion, fatigue, and vigorwere originally identified using factor analytic techniques in the 1960s (McNair et al. 1981). In this experiment, standard POMS instructions were given to the subjects, including directions to mark how they felt “right now.” Line tests have been popular since the 1920s (A&en 1%9). Our version has six lOO-mmlines labeled, respectively, “irritable,” “clear-headed,” “energetic,” “nervous,” “tired,” and “depressed.” These labels were felt to be vivid, nonpejorative, and comparable to the POMS factors. One end was labeled “least ever,” the other “most ever.” Subjects were told to recall Methods when they had experienced these extremes and Subjects to compare their present state to those times. Twenty depressed inpatients provided informed They were directly reminded of the significance consent, then ingested, in randomized order, 40 of an extreme or central response. The PBRS is a trained observer’s scale demg methylphenidate orally and either placebo (n = 10) or d-amphetamine (n = 10) at 9:00 veloped in the late 1970s by members of the NIMH Psychogenetics Section. It includes 20 AM on 2 consecutive days. Subjects completed both instruments and were evaluated on the Psy- dimensions frequently altered by stimulants. Reliability has been documented (Numberger et al. 1981), and it demonstrates face validity. Six FromtheDepgmnent of Psychiatry,Universityof KentuckyMedical scores were derived from the 20 PBRS items to Center, L.exington,KY. compare with the six POMS factors: anxiety Supportedin patt by BiomedicalResearchSupportGrant 2-50% (PBRS) = Tension (POMS); increased activity RRo5374. Addrew reprint rtque~ts to Dr. Karley Y. Little, Departmentof and increased speech minus decreased activity PSychiah’y,Amex II, Room 206, Universityof Kentucky,Lexand decreased speech (PBRS) = Vigor (FOMS); @ton, KY 40536. ReceivedFebruary17, 1988;revisedJune 6, 1988. depression and crying (PBRS) = Depression 0 1989Societyof BiologicalPsychiatry
m-3223/89/$03.50
BIOL PSYCHIATRY 1989;25:645-647
646
Brief Report5
(POMS); sleepy (PBRS) = Fatigue (POMS); distractible (PBRS) = Confusion (POMS); and irritable and demandingness (PBRS) = Anger (POMS). Statistical Procedures Change scores at + 90 and + 150 min on both the POMS and VAS were correlated with the PBRS change scores using Pearson’s productmoment. Correlation coefficients were Fisher Ztransformed and a four-way Analysis of Variance (ANOVA) performed for time, drug, instrument. and subscale factors.
of 24 conditions, including 3 of 4 on the Confusion subscale. Baseline scores before drug ingestion showed POMS scores were significantly correlated with PBRS scores in 61% of comparisons versus 50% for the VAS. After active dmg, 66% of POMS versus 50% of VAS change scores were significantly correlated with PBRS change scores. The four-way ANOVA revealed an overall instrument effect (P < 0.01) and a trend toward overall subscale X ins~ent effect (p = 0.08). On individual subscales, there were significant instrument x subscale differences. The POMS mean r-values were greater on Confusion, Fatigue, and Depression.
Results As seen in Table 1, the POMS change scores were better correlated with those after the PBRS than were the VAS at 14 of 24 conditions. The VAS was better correlated at 4 of 24 conditions, including 3 of 4 Anger subscale conditions. Neither instrument was significantly correlated at 6
Table 1. InstrumentMost
Reliably
Sensitive
Discussion These results, although limited in scope, suggest that the POMS is more reliable as it achieved lower variability and greater statistical correlations with the observer’s ratings. However, considering the brevity and ad hoc nature of our
to Change” 40 mg Methylphenidate
20 mg d-Amphetamine +9Omin Tension POMS (2) VAS Fatigue WMS
(3)
VAS (1) Depression poMS (3) VAS
NS
*r = 0.84, p = 0.0008 r = 0.50, NS
*r = 0.91, p = 0.0001 r = 0.70, p = 0.01
Confusion POMS (It
+ 150 min
NS
*I = 0.83, P = 0.01 r = 0.31, NS
*r = 0.89, p = 0.0@2 r = 0.70, p = 0.02
+90 min
+ 150 min
*r = .64.p = ,002 r = .49, p = .02
*r = so, p = .02 r = .38. N.S.
*r = 0.49, p I= 0.03 r = 0.45. p = 0.03
r = 0.51,p *r = 0.74,~
NS
= 0.02 = 0.0001
*r = 0.74, p = 0.0001 r = 0.41, p = 0.05
*r = 0.61. p = 0.004 NS
NS
(VASt Anger POMS (1) VAS (3)
r = 0.65, p = 0.03 *r = 0.68, p = 0.02
NS *r = 0.71,p = 0.01
NS *r = 0.45. p = 0.03
*r = 0.59, p = 0.006 r = 0.45, p = 0.03
Vigor F’OMS (4) VAS
*r = 0.76, p = 0.007 NS
*r = 0.67, p = 0.03 r = 0.63, p = 0.04
*r = 0.59, p = 0.007 r = 0.53. p = 0.009
*r = 0.54, p = 0.01 NS
“Based on r = values generated in a correlational comparison to observer’s ratings. Numbers in parentheses am comparisons in which one instrument was superior: POMS ( 14). VAS (4).
BIOL PSYCHIATRY 1989;25:645-647
Brief Reports
VAS instrument, its performance might not appear that unfavorable. On the Anger subscale, the VAS correlated better with the objective ratings (irritable and demandingness), suggesting that optimal construct labels (“irritable” in this case) might provide improved concurrent validity. However, on the most clearly comparable and clinically significant subscale-Depression-the POMS was superior. These results suggest some caution for investigators in choosing an instrument for detecting acute drug changes. More extensive sampling is achieved by the ROMS, which poses similar questions a number of times from slightly different semantic perspectives (Are you miserable? . . . dependent? . . . discouraged? etc.). In clinical (and practical) usage, moods refer to complex families of related sensations, feelings, and thoughts. Individuals vary as to which sensations, feelings, and thoughts they include within a mood boundary, how central or peripheral they conceptual& each of these phenomena, and how much each actually affects behavior. Unless the VAS label can crystallize the varied sensations,
647
feelings, and thoughts after a drug, the VAS as compared to multiitem scales like the ROMS or the ARC1 (Haertzen 1974) would seem mildly inferior. Despite these reservations, continued efforts at standardizing VASs and understanding the appropriate contexts for their use seem worthwhile.
References Aitken RCB (1969): Measurement of feelings using visual analogue scales. Proc R Sot Med 62:989993. Haertzen CA (1974): An overview of Addiction Research Center Inventory Scales (ARCI): An appendix and manual of scales. Washington, DC: U.S. Government Printing Office. McNair DM, Lorr M, Droppleman LF (1981): Profile of Mood States Manual. San Diego: EDITS Numberger JR Jr, Gerson ES, Jimerson DC, Buchsbaum MS, Gold P, Brown G, Ebert M (1981): Pharmacogenetics of d-amphetamine response in man. In Get-son ES et al (eds), Genetic Research Strategies for Psychobiology and Psychiatry.
Boxwood Press, pp 257-268.
645
Detecting Acute Drug Effects Karley Y. Little
Introduction Both the Profile of Mood States (POMS) and Visual Analogue Scales (VAS or 100~mm line tests) have been used to detect acute drug effects in humans. Recently, there has been increased use of VAS alone because of easily perceived advantages, such as being nontiring, easy to score, and replicable without carryover cuing, as well as having face validity. Compared to the POMS, it is unclear if VAS are more sensitive and straightforward or are less reliable and susceptible to lapses in concentration or impulsivity. VAS are clearly less validated, as no standardized forms exist and users typically label extremes with their own construct. In this experiment, we compared POMS and VAS results to observer’s ratings after subjects ingested stimulants.
chogenetics Behavioral Rating Scale (PBRS) 30 min before ingesting the capsules, then 90 and 150 min later.
Instruments The POMS six mood factors-anger,
depression, tension, confusion, fatigue, and vigorwere originally identified using factor analytic techniques in the 1960s (McNair et al. 1981). In this experiment, standard POMS instructions were given to the subjects, including directions to mark how they felt “right now.” Line tests have been popular since the 1920s (A&en 1%9). Our version has six lOO-mmlines labeled, respectively, “irritable,” “clear-headed,” “energetic,” “nervous,” “tired,” and “depressed.” These labels were felt to be vivid, nonpejorative, and comparable to the POMS factors. One end was labeled “least ever,” the other “most ever.” Subjects were told to recall Methods when they had experienced these extremes and Subjects to compare their present state to those times. Twenty depressed inpatients provided informed They were directly reminded of the significance consent, then ingested, in randomized order, 40 of an extreme or central response. The PBRS is a trained observer’s scale demg methylphenidate orally and either placebo (n = 10) or d-amphetamine (n = 10) at 9:00 veloped in the late 1970s by members of the NIMH Psychogenetics Section. It includes 20 AM on 2 consecutive days. Subjects completed both instruments and were evaluated on the Psy- dimensions frequently altered by stimulants. Reliability has been documented (Numberger et al. 1981), and it demonstrates face validity. Six FromtheDepgmnent of Psychiatry,Universityof KentuckyMedical scores were derived from the 20 PBRS items to Center, L.exington,KY. compare with the six POMS factors: anxiety Supportedin patt by BiomedicalResearchSupportGrant 2-50% (PBRS) = Tension (POMS); increased activity RRo5374. Addrew reprint rtque~ts to Dr. Karley Y. Little, Departmentof and increased speech minus decreased activity PSychiah’y,Amex II, Room 206, Universityof Kentucky,Lexand decreased speech (PBRS) = Vigor (FOMS); @ton, KY 40536. ReceivedFebruary17, 1988;revisedJune 6, 1988. depression and crying (PBRS) = Depression 0 1989Societyof BiologicalPsychiatry
m-3223/89/$03.50
BIOL PSYCHIATRY 1989;25:645-647
646
Brief Report5
(POMS); sleepy (PBRS) = Fatigue (POMS); distractible (PBRS) = Confusion (POMS); and irritable and demandingness (PBRS) = Anger (POMS). Statistical Procedures Change scores at + 90 and + 150 min on both the POMS and VAS were correlated with the PBRS change scores using Pearson’s productmoment. Correlation coefficients were Fisher Ztransformed and a four-way Analysis of Variance (ANOVA) performed for time, drug, instrument. and subscale factors.
of 24 conditions, including 3 of 4 on the Confusion subscale. Baseline scores before drug ingestion showed POMS scores were significantly correlated with PBRS scores in 61% of comparisons versus 50% for the VAS. After active dmg, 66% of POMS versus 50% of VAS change scores were significantly correlated with PBRS change scores. The four-way ANOVA revealed an overall instrument effect (P < 0.01) and a trend toward overall subscale X ins~ent effect (p = 0.08). On individual subscales, there were significant instrument x subscale differences. The POMS mean r-values were greater on Confusion, Fatigue, and Depression.
Results As seen in Table 1, the POMS change scores were better correlated with those after the PBRS than were the VAS at 14 of 24 conditions. The VAS was better correlated at 4 of 24 conditions, including 3 of 4 Anger subscale conditions. Neither instrument was significantly correlated at 6
Table 1. InstrumentMost
Reliably
Sensitive
Discussion These results, although limited in scope, suggest that the POMS is more reliable as it achieved lower variability and greater statistical correlations with the observer’s ratings. However, considering the brevity and ad hoc nature of our
to Change” 40 mg Methylphenidate
20 mg d-Amphetamine +9Omin Tension POMS (2) VAS Fatigue WMS
(3)
VAS (1) Depression poMS (3) VAS
NS
*r = 0.84, p = 0.0008 r = 0.50, NS
*r = 0.91, p = 0.0001 r = 0.70, p = 0.01
Confusion POMS (It
+ 150 min
NS
*I = 0.83, P = 0.01 r = 0.31, NS
*r = 0.89, p = 0.0@2 r = 0.70, p = 0.02
+90 min
+ 150 min
*r = .64.p = ,002 r = .49, p = .02
*r = so, p = .02 r = .38. N.S.
*r = 0.49, p I= 0.03 r = 0.45. p = 0.03
r = 0.51,p *r = 0.74,~
NS
= 0.02 = 0.0001
*r = 0.74, p = 0.0001 r = 0.41, p = 0.05
*r = 0.61. p = 0.004 NS
NS
(VASt Anger POMS (1) VAS (3)
r = 0.65, p = 0.03 *r = 0.68, p = 0.02
NS *r = 0.71,p = 0.01
NS *r = 0.45. p = 0.03
*r = 0.59, p = 0.006 r = 0.45, p = 0.03
Vigor F’OMS (4) VAS
*r = 0.76, p = 0.007 NS
*r = 0.67, p = 0.03 r = 0.63, p = 0.04
*r = 0.59, p = 0.007 r = 0.53. p = 0.009
*r = 0.54, p = 0.01 NS
“Based on r = values generated in a correlational comparison to observer’s ratings. Numbers in parentheses am comparisons in which one instrument was superior: POMS ( 14). VAS (4).
BIOL PSYCHIATRY 1989;25:645-647
Brief Reports
VAS instrument, its performance might not appear that unfavorable. On the Anger subscale, the VAS correlated better with the objective ratings (irritable and demandingness), suggesting that optimal construct labels (“irritable” in this case) might provide improved concurrent validity. However, on the most clearly comparable and clinically significant subscale-Depression-the POMS was superior. These results suggest some caution for investigators in choosing an instrument for detecting acute drug changes. More extensive sampling is achieved by the ROMS, which poses similar questions a number of times from slightly different semantic perspectives (Are you miserable? . . . dependent? . . . discouraged? etc.). In clinical (and practical) usage, moods refer to complex families of related sensations, feelings, and thoughts. Individuals vary as to which sensations, feelings, and thoughts they include within a mood boundary, how central or peripheral they conceptual& each of these phenomena, and how much each actually affects behavior. Unless the VAS label can crystallize the varied sensations,
647
feelings, and thoughts after a drug, the VAS as compared to multiitem scales like the ROMS or the ARC1 (Haertzen 1974) would seem mildly inferior. Despite these reservations, continued efforts at standardizing VASs and understanding the appropriate contexts for their use seem worthwhile.
References Aitken RCB (1969): Measurement of feelings using visual analogue scales. Proc R Sot Med 62:989993. Haertzen CA (1974): An overview of Addiction Research Center Inventory Scales (ARCI): An appendix and manual of scales. Washington, DC: U.S. Government Printing Office. McNair DM, Lorr M, Droppleman LF (1981): Profile of Mood States Manual. San Diego: EDITS Numberger JR Jr, Gerson ES, Jimerson DC, Buchsbaum MS, Gold P, Brown G, Ebert M (1981): Pharmacogenetics of d-amphetamine response in man. In Get-son ES et al (eds), Genetic Research Strategies for Psychobiology and Psychiatry.
Boxwood Press, pp 257-268.