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Association of levels of N-acetyl-beta-glucosaminidase with severity of psychiatric symptoms in panic disorder
PSYCHIATRY RESEARCH Psychiatry Research 60 (1996) 185-190
ELSEVIER
Association of levels of N-acetyl-beta-glucosaminidase with severity of psychiatric symptoms in panic disorder Michael J. G a r v e y *a'b, Russell Noyes, Jr. b apsychiatry Service, VA Medical Center. lowa City, 1,4 52246, USA bDepartment of Psychiatry, University of Iowa College of Medicine, Iowa City. 1,4 52242, USA
Received 6 December 1994; revised 3 July 1995; accepted 7 December "-,995
Abstract Urinary levels of N-acetyl-/~-glucosaminidase (NAG) were measured in 58 patients with panic disorder. NAG levels were found to be significantly related to the severity of 23 of 72 mood states, measured by the Profile of Mood States, which were grouped in three categories: hostility or irritability, sadness, and panic. A similar result was found in a previous study of bipolar patients. NAG levels were also related to scores on the Hamilton Rating Scale for An,dety and the Sheehan Patient-Rated Anxiety Scale. It is speculated that NAG could be a marker for sero*onin. Keywords: Mood states; Serotonin; Anxiety disorder
1. Introduction
N-acetyl-/~-glucosaminidase(NAG) is an enzyme found in the lysosomes of most animal cells. Lysosomes contain numerous enzymes that are necessary for the degradation and disposal of va~ous parts of the cell. NAG splits the chemical bonds of certain glycosides that form structural components of the cells (Thompson et al., 1973). We have previously shown that NAG levels in patients with panic disorder differ from those in healthy volunteers (Garvey et al., 1993). Signifi-
cant associations have been reported between urinary NAG levels and the severity of various psychiatric symptoms in a group of bipolar disorder patients (Garvey and Noel, 1992) and, to a lesser extent, in a group of unipolar patients (Garvey and Noel, 1995). To explore whether these preliminary findings might extend to other conditions, possible associations between the severity oi ' various mood states (symptoms) and urinary NAG levels were assessed in a group of patients with panic disorder. 2. Methods
* Corresponding author, Psychiatry Service, VA Medical Center, Iowa City, IA 52246, USA; Tel: +i 319 339-7176; Fax: +! 319 339-7171.
Patients were solicited through advertisements. Patients were screened with the Structured Clinical
0165-1781/96/$15.00 © 1996 Elsevier Science Ireland Ltd. All rights reserved Pll: SO165-i 781(96)02761-8
186
M.,l. Garvey, R. Noyes, Jr./Psychiatry Research 60 (1996) 185-190
Interview for DSM-III (SCID, Upjohn version; Spitzer and Williams, 1982). Those who met DSMlllcriteria for panic disorder were invited to participate in a treatment study (Ballenger et al., 1988; Kathol et al., 1988). Patients were asked about various features of their illness including demographics, longitudinal course, and comorbidity. Various instruments were used to assess the severity of symptoms, including the Hamilton Rating Scale for Anxiety (HRSA; Hamilton, 1959), the Sheeha:~ Patient-Rated Anxiety Scale (Sheehan, 1986), and the research version of the Profile of Mood States (POMS; McNair et al., 1972). The POMS is a self-assessment that rates 72 mood states on a 5-point scale (0-4: absent to extreme). Examples of POMS mood states are as follows: angry, blue, panicky, annoyed, and elated. Ratings were done as part of the pretreatment assessment. The POMS has some similarities to the Symptom Checklist-90, which was used in a previous investigation of the relationship of NAG to symptom severity (Garvey and Noel, 1992). Consenting patients were invited to collect urine samples for studies of various biological substances. The majority of patients (48 of 58 or 83%) were not taking psychotropic medications when they sought treatment. The other 10 patients were taking benzodiazepines. They stopped taking these medications at least I week before collecting urine samples. In previous studies, we have not found any relationship between use of a variety of psychotropic medications, including lithium, and NAG levels (Garvey et al., 1982, 1988). Some nephrotoxic medications and certain diseases can cause NAG elevations (Wollen and Turner, 1965; Burry et al., 1976; Kunin et al., 1978; Mansell et ai., 1978; Dubach and Schmidt, 1979; Maruhn, 1979; Whiting et al., 1979; Reglero et al., 1980; Tucker et al., 1980; Price, 1982; Alderman et al., 1983). Patients with serious medical illnesses were excluded from the study. To the extent that any inappropriate patients were inadvertently included, it should have decreased our ability to find significant relationships between NAG and severity of mood states as measured by the POMS. Urine collection procedures have been detailed elsewhere (Kathol et al., 1988). Briefly, 24-h samples were collected and frozen at -20°C. NAG was
analyzed approximately 2-3 years after the urine collections. We have found NAG levels to remain stable for more than 4 years when frozen at -20°C (unpublished data). Urine samples were analyzed for NAG by a method described by Price et al. (1970). Aliquots of urine were mixed with buffered solution containing 4-methylumbelliferyl-N-acetyl-O-D-glucosaminide for a predetermined time. NAG catalyzed the release of the fluorescent compound 4-methylumbelliferyl. The NAG enzyme activity was calculated from the quantity of released substrate, which was measured by a fluorometer (Price et al., 1970; Tucker et al., 1975; Wellwood et al., 1976). To adjust for variations in urine flow, enzyme activity is divided by the concentration of creatinine ~T/ell rood et al., 1976). The final NAG value is reported in nanomoles of released substrate per hour per milligram of creatinine. Previous studies have demonstrated that the NAG assay is simple, reliable, and has a coefficient of variation for duplicate samples of approximately 2% (Tucker et al., 1975; Wellwood et al., 1976). Because psychiatric patients with the same DSM-III diagnosis are likely to be biologically heterogeneous, we decided to examine subgroups o? panic patients. A history of depression was used to divide patients because of the finding that panic disorder patients with a history of depression differ biologically from patients without such a history (Kathol et al., 1988). In a separate study of patients with generalized anxiety disorder, we found a biologically meaningful difference ben tween patients with and without coexistent disorders (Garvey et al., 1995). Other studies of mood disorders have also shown biological differences between patients with and without coexistent psychiatric disorders. These findings suggest that subgrouping patients based on the presence or absence of coexistent psychiatric disorders may be a reasonable way to explore potential biological differences among patients with the same Axis I disorder. A Pearson's correlation coefficient was calculated by comparing the baseline NAG levels to the severity ratings for each of the 72 baseline POMS items. POMS factor scale scores (McNair et al., 1972) were also correlated to NAG levels.
M.J. Garvey, R. Noyes, Jr./Psychiatry Research 60 (1996) 185-i90
3. Results Ninety-one patients entered the study. Eightyfive patients collected at least one urine sample that was analyzed for NAG. Twenty-seven of these patients had a history of a mood disorder. Their NAG levels were significantly associated with the severity of only one of 72 POMS items, a result likely to be a chance finding, in view of the number of tested comparisons. The other 58 patients with no history of mood disorder showed several significant associations between NAG level and severity of va~ous mood states, and they are the subject of this report. Fifty-three percent of the group of 58 patients were women with a mean age of 37 years (SD-10) and a mean HRSA score of 1~ (SD = 9). The baseline urinary NAG level was 16 (SD --" 12), which was essentially the same as that for the 27 patients with a past history of mood disorder: 16 (SD = 10). Previous reports have suggested a normal range for NAG of 0-100 units (Price et al., 1970; "fucker et al., 1975; Wellwood et al., 1975). For comparison purposes, mean NAG levels from 76 healthy subjects examined in three of our other studies ranged from 27 to 44 (SD = -- 17) (Garvey et al., 1982, 1988, 1990). NAG levels in healthy subjects were significantly different from levels in panic disorder patients (Garvey et al., 1993). The mean NAG level in the group of bipolar patients discussed in the Introduction was approximately 57 (SD = -25) (Garvey et al., 1990; Garvey and Noel, 1992)~ significantly higher than the level in healthy subjects (Garvey et al., 1990). Table I shows the POMS items that were significantly associated with NAG. Severity ratings for 23 of the 72 mood states were related to NAG levels. All relationships with undesirable mood states were positively correlated to NAG levels, whereas the only desirable mood state listed in Table 1 (cheerfulness) was negatively associated with NAG. There were occasional significant correlations between some of the POMS items and either age or gender. Since this could have confounded the relationships found for NAG and individual POMS items, a multiple linear regression was calculated
187
Table 1 Relationship of NAG to mood states (n = 58) Mood state
Tense Angry Listless On edge Blue Spiteful Hopeless Panicky Annoyed Cheerful Resentful Bewildered Uneasy Bitter Restless Gloomy Desperate Nervous Weary Uncertain Anxious Terrified Bad temper
POMS ~ore
pa
Mean SD
Correlation coefficient with NAG level
2.4 1.! 1.3 0.8 1.2 I.! 1.9 1.2 1.1 !.2 0.5 0.9 0.5 0.9 2.1 1.1 !.5 i.0 1.8 !.0 0.8 1.1 0.8 I.i !.9 1.3 0.6 0.9 2.0 i.3 I. ! 1.2 0.9 1.3 2.3 1.2 1.4 1.1 !.8 1.3 2.4 I.! I.I 1.3 0.9 1.1
0.324 0.319 0.374 0.354 0.279 0.341 0.267 0.307 0.333 -0.256 0.344 0.362 0.356 0.286 0.289 0.272 0.355 0.326 0.271 0.259 0.276 0.337 0.331
0.0131 0.0148 0.0039 0.0064 0.0338 0.0088 0.0426 0.0192 0.0105 0.0446 0.0082 0.0052 0.0062 0.0298 0.0276 0.0387 0.0062 0.0126 0.0398 0.0498 0.0359 0.0097 0.01 ! !
Note. POMS, Profile of Mood States. NAG, N-acetyl-/3-glucosaminidase, aSignificance level of Pearson correlation.
fo~"each of the POMS items listed in Table 1. Age, gender, and NAG value were the independent variables, and each POMS item listed in Table 1 was used as the dependent variable in separate calculations. The P values for the partial coefficients for NAG (after the effects of age and gender were controlled) were all significant except for three variables, two of which were almost significant. The NAG partial P values for these three POMS items were as follows: cheerful (0.138), terrified (0.066), and tense (0.057). Table 2 lists the results of the correlations of NAG to the POMS factor scales. Four of the six scale scores were significantly associated with NAG levels. To control for possible effects that age or gender might have h~d on these results, a multiple regression was calculated for each factor scale. The independent variables were age, gender,
188
M.J. Garvey, R. Noyes, Jr. / Psychiatry Research 60 (1996) 185-190
4. Discussion
Table 2 Relationship of NAG to POMS factor scales (n = 58) POMS s c a l e
Correlation coefficient with NAG level
pa
Partial pb
Tension-anxiety Depressiondejection Confusionbe,,,Idc . . . . . t Anger-hostility Visor.activity Fatigue-inertia Total mood disturban~=
0.259 0.374
0.0501 0.0039
0.0272 0.0011
0.328
0.0119
0.0075
0.434 0.01 ! 0.214 0.387
0.0007 0.9360 • 1067 u,~./
0.000 i 0.6171 0,035 0.~008
Note. POMS, Profile of Mood States. NAG, N-acetyl-O-glucosaminidase, aSignificance level of Pearson correlation, bpartial P value from multiple regression calculation, controlling for effects of age and gender.
and NAG. The dependent variable was the score of each POMS factor scale. As shown in Table 2, the partial P values for the relationship of NAG to the POMS scale scores were highly significant for all but one of the six scales. The only exception was the vigor-activity scale, which is the only scale that tests positive attributes (e.g., carefree, alert, and cheerful). NAG levels were also significantly associated with the baseline HRSA score (r = 0.379, df = 57, P = 0.003). The total score from the 35-item Sheehan Clinician-Rated Anxiety Scale was also significantly associated with NAG levels (r = 0.431, df= 57, P = 0.0007). NAG was not correlated with age (r = 0.08, df = 57, P = 0.55). NAG levels were lower in men (n = 27) than in women (n = 31): 12 4- 9 vs. 20 4- 13 (t = - 2 . 5 , df= 56, P=0.015, two-tailed Student t test). NAG was not associated with illness duration. The mean NAG level of the 48 patients who were not taking psychotropic medications was nearly the same as the level of the 10 patients who stopped benzodiazepines a week or more before the urine collection: mean 4- SD = 16 4- 1 i vs. 16 4- 14. A multiple regression was calculated to control for possible effects of gender and age. The partial correlation coefficient for the relationship of NAG and benzodiazepine use was not significant (P = 0.57).
NAG levels of study patients were significantly associated, with 23 of 72 POMS items. The large number of comparisons performed should have produced a few significant associations by chance alone, but not as many as were found, namely 23. We did not make Bonferroni adjustments because the analyses were exploratory and no specific hypothesis was to be tested° Such_ a correction _could have been too restrictive and eliminated preliminary findings that may merit further investigation. Several of the mood states listed in Table 1 can be grouped into categories such as (1) hostility or irritability, (2) sadness, and (3) panic. In a study of bipolar patients, the severity of these same psychiatric symptoms or categories (plus several other symptoms) was significantly associated with NAG (Garvey and Noel, 1992). What might account for the association of NAG to the severity of certain mood symptoms? We have speculated that one possibility is that NAG may be associated with serotonin turnover (Garvey and Noel, 1992). Several of the symptoms or mood states associated with NAG in this study or the bipolar study (Garvey and Noel, 1992) may involve serotonin as a neurotransmitter: for example, anxiety (Kahn et al., 1991) and hostility (Copenhaver et al., 1978; Broderick and Lynch, 1982; Coccaro, 1989; Coccaro et al., 1989). The hypothesis that NAG could be associated with serotonin metabolism was supported in an investigation of ours that showed a significant relationship between urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) and NAG in a selected group of anxiety patients (Garvey et al., 1995). We have offered other indirect support for the postulate that NAG may be associated with serotonin turnover (Garvey and Black, 11993). Our data and hypotheses are clearly preliminary and require further testing and verification. If future research were to show an association between urinary NAG and central nervous system serotonin activity, it could provide a simple test to monitor serotonin status. Serotonin function has most often been assessed by measuring the serotonin metabolite 5-HIAA in the cerebrospinal fluid (CSF). The CSF is obtained by a lumbar spinal ~ap, a procedure that requires time, involves
M.J. Garvey, R. Noyes, Jr. /Psychiatry Research 60 (1996) 185-190
some risk, and cannot be performed routinely. An assessment of serotonin status might someday be of value in the selection of an antidepressant for a particular patient or for follow-up of potentially suicidal patients (,~sberg et ~1., 1976; Roy et al., 1986; Nordstr6m et al., 1994). In summary, urinary NAG was significantly associated with the severity of several mood states (symptoms) in a subgroup of panic disorder patients. The severity of several of these same symptoms was associated with NAG in a previous study of bipolar patients. Acknowledgments Support for this study was provided by the Department of Veterans Affairs and the University of Iowa College of Medicine. References Alderman, M.H., Melcher, L•, Drayer, D.E. and Reidenberg, M.M. (1983) Ir~creased excretion of N-acetyl-beta-glucosaminidase in essential hypertension and its decline with antihypertensive therapy. N Engl J Med 309, 1213-1217. ,~sberg, M., Trfiskman, L. and Thor~n, P. (1976) 5-HIAA in the cerebrospinal fluid - - A suicide predictor? Arch Gen Psychiatry 33, 1193-1197. Ballenger, J.C., Burrows, G.D., DuPont, R.L., Jr., Lesser, I.M., Noyes, R., Jr., Pecknold, J.C,, Rifkin, A. and Swinson, R.P. (1988) Alprazolam in panic disorder and agoraphobia: results from a multicenter trial. I. Efficacy in short-term treatment. Arch Gen Psychiatry 45, 413-422. Broderick, P. and Lynch, V. (1982) Behavioral and biochemical changes induced by lithium and L-tryptophan in muricidal rats. Neuropharmacology 671, 671-679. Burry, H.C., Dieppe, P.A., Bresnihan, F.B. and Brown, C. (1976) Salicylates and renal function in rheumatoid arthritis. Br Med J !, 613-615. Coccaro, E.F. (1989) Central serotonin and impulsive aggression. Br J Psychiatry 155, 52-62. Coc~aro, E.F., Siever, L.J., Klar, H.M., Mauler, G., Cochrane, K., Cooper T.B., Mohs, R.C. and Davis, K.L. (1989) Serotonergic studies in patients with affective and personality disorders. Correlates with suicidal and impulsive aggressive behavior. Arch Gen Psychiatry 46, 587-599. Copenhavcr, J H, c.~.~^.~ R.L. and Carver, ~A ~ i ! o ' ~ Effect of serotonin on Y-maze retention and hippocampal protein synthesis in rats. Pharmacol Biochem Behav 8, 263-270. Dubach, A.C. and Schmidt, A. (1979) Diagnostic Significance of Enzymes and Protein in Urine. Hans Huber Publishers, Bern, Stuttgart, Vienna. Garvey, M.J. and Black, D. (1993) An association between the •
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lysosomal enzyme NAG and urinary free cortisol and platelet imipramine binding. J Psychiatr Res 27, 241-245. Garvey, M.J., Furlong, C., Schaffer, C.B. and Adelman, R. (1988) Elevation of the renal enzyme N-acetyl-betaglucosaminidase in affectively disordered patients. Acta Psychiatr Scand 77, 247-252. Garvey, M.J. and Noel, M. (1992) Association of N-acetylbeta-glucosaminidase with specific psychiatric symptoms in bipolar patients. Psychiatry Res 47, 129-139. Garvey, M.J. and Noel, M. 0995) Association of NAG levels with specific psychiatric symptoms in unipolar patients. J Psychiatry Neurosci 20, 20-24. Garvey, M.J., Noyes, R.J., Cook, B., Barrickman, L., Noel, M. and Ghosheh, R. (1990) Elevated levels of N-acetyl-betaglucosaminidase in affective disorders and chemical dependence. J Affect Disord 19, 279-285. Garvey, M.J., Noyes, R.J., Woodman, C. and Laukes, C. (1993) A biological difference between panic disorder and general anxiety disorder. Biol Psychiatry 34, 572-575. Garvey, M.J., Noyes, R.J., Woodman, C. and Laukes, C. (1995) The association of the serotonin metabolite, 5HIAA, to the lysosomal enzyme N-acetyl-0-glucosaminidase. Neuropsychobiology 32, 75-78. Garvey, M.J., Tuason, V.B., Blomquist, C.H. and Hwang, S. (1982) Use of renal enzymes to evaluate nephrotoxicity in lithium treated patients. Br J Psychiatry 141, 420-422. Hamilton, M. (1959) The assessment of anxiety states by rating. Br J Med Psychol 32, 50-55. Kahn, R.S., Kalus, O., Wetzler, S. and van Praag, H. (1991) The Role of Serotonin in the Regulation of Anxiety. Brunner/Mazel, New York. Kathol, R.G., Noyes, R.J., Lopez, A.L. and Reich, J. (1988) Relationship of urinary free cortisol levels in patients with panic disorder to symptoms of depression and agoraphobia• Psychiatry Res 24, 21 !-221. Kunin, C.M., Chesney, R.W., Craig, W.A., England, A.C. and DeAngelis, C. (1978) Enzymuria as a marker of renal injury and disease: studies of N-acetyl-beta-glucosaminidase in the general population. Pediatrics 62, 751-760. Mansell, M.A., Jones, N.F., Ziroyannis, P.N. and Marson, W.S. (1978) N-acetyl-beta-glucosaminidase: a new approach to screening hypertensive patients for renal disease. Lancet 11, 803-805. Marnhn, D. (1979) Evaluation of urinary enzyme patterns in patients with kidney disease and primary benign hypertension. Curt Prob Clin Biochem 9, 135-149. McNair, D.M., Lorr, M. and Droppleman, L.F• (1972) Profile of Mood States (Manual). Educational and Industrial Testing Service, San ~ego. Nordstr6m, P., Samuelsson, M., ~sberg, M., Tr,~skmanBendz, L., ,/~berg-Wistedt, .~., Nordin, C. and Bertilsson~ L. (I 994) CSF 5-HIAA predicts suicide risk after attempted suicide. Suicide Life Threat Behav 24, 1-9. Price, R.G. (1982) Urinary er~jrnes, nephrotoxicity, and renal disease. Toxicology 23, 99-135. Price, R.G., Dance, N., Richard, B. and Cateil, W.R. (1970) The excretion of N-acetyl-beta-glucosaminidase and betaglactosidase following surgery to the kidney. Clin Chim Acta 27, 65-72.
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Reglero, A., Carretero, I. and Cabezas, J.A. (1980) Increased serum alpha-L-fuctosidase and beta-N-acetylglucoseminidase activities in diabetic, cirrhotic., and gastric cancer patients. Clin Chim Acta 103, 155-158. Roy, A., ~8ren, H., Pickar, D., Linnoila, M., Doran, A.R., Cutler, N.R. and Paul, S.M. (1986) Reduced CSF concentrations of homovanillic acid and homovanillic acid to 5.hydroxyindoleacetic acid ratios in depressed patients: relationship to suicidal behavior and dexamethasone nonsuppression. Am J Psychiatry 143, 1539-1545. Sheehan, D. (1986) The Anxiety Disease. Rev. edn. Bantam, New York. Spitzer, R.L. and Williams, B.W. (1982) Structured Clinical In. terview for DSM-IIi. Biometrics Research Department, New York State Psychiatric Institute, New York. Thompson, J.N., Stoolmiller, A.C., Matalion, R. and Dad: man, A. (1973) N-acetyl-beta-hexosaminidase: role in degradation of glycosominoglycans. Science 181,866-867. Tucker, S.M., Boyd, P., Thompson, A.E. and Price, R.G. (1975) Automated assay of N-acetyi-beta-giucosaminidase
in a normal pathological human urine. Clin Chim Acta 62, 333-339. Tucker, S.M., Pierce, R.J. and Price, R.G. (1980)Characterization of human N-acetyl-0-glucosaminidase isoenzymes as an indicator of tissue damage in disease. Clin Chim Acta 102, 29-40. Wellwood, J.M., Ellis, B.G., Price, R.G., Hammond, K., Thompson, A.E. and Jones, N.F. (1975) Urinary N-acetylbeta-D-glucosaminidase activities in patients with renal disease. Br Med J 3, 408-411. Wellwoed, J.M., Price, R.G., Ellis, B.G. and Thompson~ A.E. (1976) A note on the practical aspects of the N-acetyi-betagiucosaminidase in human urine. Clin Chim Acta 69, 85-91. Whiting, P.H., Ross, I.S. and Borthwick, L. (1979) Serum and urine N.acetyl.beta-giucosaminidase in diabetics on diagnosis and subsequent treatment, and stable insulin dependent diabetics. Clin Cbim Acta 92, 459-463, Wollen, J.W. and Turner, P. (1965) Plasma N-acetyi-betagiucosaminidase and beta-giucuronidase in health and disease. Clin Chim ,4cta 12, 671-683.
ELSEVIER
Association of levels of N-acetyl-beta-glucosaminidase with severity of psychiatric symptoms in panic disorder Michael J. G a r v e y *a'b, Russell Noyes, Jr. b apsychiatry Service, VA Medical Center. lowa City, 1,4 52246, USA bDepartment of Psychiatry, University of Iowa College of Medicine, Iowa City. 1,4 52242, USA
Received 6 December 1994; revised 3 July 1995; accepted 7 December "-,995
Abstract Urinary levels of N-acetyl-/~-glucosaminidase (NAG) were measured in 58 patients with panic disorder. NAG levels were found to be significantly related to the severity of 23 of 72 mood states, measured by the Profile of Mood States, which were grouped in three categories: hostility or irritability, sadness, and panic. A similar result was found in a previous study of bipolar patients. NAG levels were also related to scores on the Hamilton Rating Scale for An,dety and the Sheehan Patient-Rated Anxiety Scale. It is speculated that NAG could be a marker for sero*onin. Keywords: Mood states; Serotonin; Anxiety disorder
1. Introduction
N-acetyl-/~-glucosaminidase(NAG) is an enzyme found in the lysosomes of most animal cells. Lysosomes contain numerous enzymes that are necessary for the degradation and disposal of va~ous parts of the cell. NAG splits the chemical bonds of certain glycosides that form structural components of the cells (Thompson et al., 1973). We have previously shown that NAG levels in patients with panic disorder differ from those in healthy volunteers (Garvey et al., 1993). Signifi-
cant associations have been reported between urinary NAG levels and the severity of various psychiatric symptoms in a group of bipolar disorder patients (Garvey and Noel, 1992) and, to a lesser extent, in a group of unipolar patients (Garvey and Noel, 1995). To explore whether these preliminary findings might extend to other conditions, possible associations between the severity oi ' various mood states (symptoms) and urinary NAG levels were assessed in a group of patients with panic disorder. 2. Methods
* Corresponding author, Psychiatry Service, VA Medical Center, Iowa City, IA 52246, USA; Tel: +i 319 339-7176; Fax: +! 319 339-7171.
Patients were solicited through advertisements. Patients were screened with the Structured Clinical
0165-1781/96/$15.00 © 1996 Elsevier Science Ireland Ltd. All rights reserved Pll: SO165-i 781(96)02761-8
186
M.,l. Garvey, R. Noyes, Jr./Psychiatry Research 60 (1996) 185-190
Interview for DSM-III (SCID, Upjohn version; Spitzer and Williams, 1982). Those who met DSMlllcriteria for panic disorder were invited to participate in a treatment study (Ballenger et al., 1988; Kathol et al., 1988). Patients were asked about various features of their illness including demographics, longitudinal course, and comorbidity. Various instruments were used to assess the severity of symptoms, including the Hamilton Rating Scale for Anxiety (HRSA; Hamilton, 1959), the Sheeha:~ Patient-Rated Anxiety Scale (Sheehan, 1986), and the research version of the Profile of Mood States (POMS; McNair et al., 1972). The POMS is a self-assessment that rates 72 mood states on a 5-point scale (0-4: absent to extreme). Examples of POMS mood states are as follows: angry, blue, panicky, annoyed, and elated. Ratings were done as part of the pretreatment assessment. The POMS has some similarities to the Symptom Checklist-90, which was used in a previous investigation of the relationship of NAG to symptom severity (Garvey and Noel, 1992). Consenting patients were invited to collect urine samples for studies of various biological substances. The majority of patients (48 of 58 or 83%) were not taking psychotropic medications when they sought treatment. The other 10 patients were taking benzodiazepines. They stopped taking these medications at least I week before collecting urine samples. In previous studies, we have not found any relationship between use of a variety of psychotropic medications, including lithium, and NAG levels (Garvey et al., 1982, 1988). Some nephrotoxic medications and certain diseases can cause NAG elevations (Wollen and Turner, 1965; Burry et al., 1976; Kunin et al., 1978; Mansell et ai., 1978; Dubach and Schmidt, 1979; Maruhn, 1979; Whiting et al., 1979; Reglero et al., 1980; Tucker et al., 1980; Price, 1982; Alderman et al., 1983). Patients with serious medical illnesses were excluded from the study. To the extent that any inappropriate patients were inadvertently included, it should have decreased our ability to find significant relationships between NAG and severity of mood states as measured by the POMS. Urine collection procedures have been detailed elsewhere (Kathol et al., 1988). Briefly, 24-h samples were collected and frozen at -20°C. NAG was
analyzed approximately 2-3 years after the urine collections. We have found NAG levels to remain stable for more than 4 years when frozen at -20°C (unpublished data). Urine samples were analyzed for NAG by a method described by Price et al. (1970). Aliquots of urine were mixed with buffered solution containing 4-methylumbelliferyl-N-acetyl-O-D-glucosaminide for a predetermined time. NAG catalyzed the release of the fluorescent compound 4-methylumbelliferyl. The NAG enzyme activity was calculated from the quantity of released substrate, which was measured by a fluorometer (Price et al., 1970; Tucker et al., 1975; Wellwood et al., 1976). To adjust for variations in urine flow, enzyme activity is divided by the concentration of creatinine ~T/ell rood et al., 1976). The final NAG value is reported in nanomoles of released substrate per hour per milligram of creatinine. Previous studies have demonstrated that the NAG assay is simple, reliable, and has a coefficient of variation for duplicate samples of approximately 2% (Tucker et al., 1975; Wellwood et al., 1976). Because psychiatric patients with the same DSM-III diagnosis are likely to be biologically heterogeneous, we decided to examine subgroups o? panic patients. A history of depression was used to divide patients because of the finding that panic disorder patients with a history of depression differ biologically from patients without such a history (Kathol et al., 1988). In a separate study of patients with generalized anxiety disorder, we found a biologically meaningful difference ben tween patients with and without coexistent disorders (Garvey et al., 1995). Other studies of mood disorders have also shown biological differences between patients with and without coexistent psychiatric disorders. These findings suggest that subgrouping patients based on the presence or absence of coexistent psychiatric disorders may be a reasonable way to explore potential biological differences among patients with the same Axis I disorder. A Pearson's correlation coefficient was calculated by comparing the baseline NAG levels to the severity ratings for each of the 72 baseline POMS items. POMS factor scale scores (McNair et al., 1972) were also correlated to NAG levels.
M.J. Garvey, R. Noyes, Jr./Psychiatry Research 60 (1996) 185-i90
3. Results Ninety-one patients entered the study. Eightyfive patients collected at least one urine sample that was analyzed for NAG. Twenty-seven of these patients had a history of a mood disorder. Their NAG levels were significantly associated with the severity of only one of 72 POMS items, a result likely to be a chance finding, in view of the number of tested comparisons. The other 58 patients with no history of mood disorder showed several significant associations between NAG level and severity of va~ous mood states, and they are the subject of this report. Fifty-three percent of the group of 58 patients were women with a mean age of 37 years (SD-10) and a mean HRSA score of 1~ (SD = 9). The baseline urinary NAG level was 16 (SD --" 12), which was essentially the same as that for the 27 patients with a past history of mood disorder: 16 (SD = 10). Previous reports have suggested a normal range for NAG of 0-100 units (Price et al., 1970; "fucker et al., 1975; Wellwood et al., 1975). For comparison purposes, mean NAG levels from 76 healthy subjects examined in three of our other studies ranged from 27 to 44 (SD = -- 17) (Garvey et al., 1982, 1988, 1990). NAG levels in healthy subjects were significantly different from levels in panic disorder patients (Garvey et al., 1993). The mean NAG level in the group of bipolar patients discussed in the Introduction was approximately 57 (SD = -25) (Garvey et al., 1990; Garvey and Noel, 1992)~ significantly higher than the level in healthy subjects (Garvey et al., 1990). Table I shows the POMS items that were significantly associated with NAG. Severity ratings for 23 of the 72 mood states were related to NAG levels. All relationships with undesirable mood states were positively correlated to NAG levels, whereas the only desirable mood state listed in Table 1 (cheerfulness) was negatively associated with NAG. There were occasional significant correlations between some of the POMS items and either age or gender. Since this could have confounded the relationships found for NAG and individual POMS items, a multiple linear regression was calculated
187
Table 1 Relationship of NAG to mood states (n = 58) Mood state
Tense Angry Listless On edge Blue Spiteful Hopeless Panicky Annoyed Cheerful Resentful Bewildered Uneasy Bitter Restless Gloomy Desperate Nervous Weary Uncertain Anxious Terrified Bad temper
POMS ~ore
pa
Mean SD
Correlation coefficient with NAG level
2.4 1.! 1.3 0.8 1.2 I.! 1.9 1.2 1.1 !.2 0.5 0.9 0.5 0.9 2.1 1.1 !.5 i.0 1.8 !.0 0.8 1.1 0.8 I.i !.9 1.3 0.6 0.9 2.0 i.3 I. ! 1.2 0.9 1.3 2.3 1.2 1.4 1.1 !.8 1.3 2.4 I.! I.I 1.3 0.9 1.1
0.324 0.319 0.374 0.354 0.279 0.341 0.267 0.307 0.333 -0.256 0.344 0.362 0.356 0.286 0.289 0.272 0.355 0.326 0.271 0.259 0.276 0.337 0.331
0.0131 0.0148 0.0039 0.0064 0.0338 0.0088 0.0426 0.0192 0.0105 0.0446 0.0082 0.0052 0.0062 0.0298 0.0276 0.0387 0.0062 0.0126 0.0398 0.0498 0.0359 0.0097 0.01 ! !
Note. POMS, Profile of Mood States. NAG, N-acetyl-/3-glucosaminidase, aSignificance level of Pearson correlation.
fo~"each of the POMS items listed in Table 1. Age, gender, and NAG value were the independent variables, and each POMS item listed in Table 1 was used as the dependent variable in separate calculations. The P values for the partial coefficients for NAG (after the effects of age and gender were controlled) were all significant except for three variables, two of which were almost significant. The NAG partial P values for these three POMS items were as follows: cheerful (0.138), terrified (0.066), and tense (0.057). Table 2 lists the results of the correlations of NAG to the POMS factor scales. Four of the six scale scores were significantly associated with NAG levels. To control for possible effects that age or gender might have h~d on these results, a multiple regression was calculated for each factor scale. The independent variables were age, gender,
188
M.J. Garvey, R. Noyes, Jr. / Psychiatry Research 60 (1996) 185-190
4. Discussion
Table 2 Relationship of NAG to POMS factor scales (n = 58) POMS s c a l e
Correlation coefficient with NAG level
pa
Partial pb
Tension-anxiety Depressiondejection Confusionbe,,,Idc . . . . . t Anger-hostility Visor.activity Fatigue-inertia Total mood disturban~=
0.259 0.374
0.0501 0.0039
0.0272 0.0011
0.328
0.0119
0.0075
0.434 0.01 ! 0.214 0.387
0.0007 0.9360 • 1067 u,~./
0.000 i 0.6171 0,035 0.~008
Note. POMS, Profile of Mood States. NAG, N-acetyl-O-glucosaminidase, aSignificance level of Pearson correlation, bpartial P value from multiple regression calculation, controlling for effects of age and gender.
and NAG. The dependent variable was the score of each POMS factor scale. As shown in Table 2, the partial P values for the relationship of NAG to the POMS scale scores were highly significant for all but one of the six scales. The only exception was the vigor-activity scale, which is the only scale that tests positive attributes (e.g., carefree, alert, and cheerful). NAG levels were also significantly associated with the baseline HRSA score (r = 0.379, df = 57, P = 0.003). The total score from the 35-item Sheehan Clinician-Rated Anxiety Scale was also significantly associated with NAG levels (r = 0.431, df= 57, P = 0.0007). NAG was not correlated with age (r = 0.08, df = 57, P = 0.55). NAG levels were lower in men (n = 27) than in women (n = 31): 12 4- 9 vs. 20 4- 13 (t = - 2 . 5 , df= 56, P=0.015, two-tailed Student t test). NAG was not associated with illness duration. The mean NAG level of the 48 patients who were not taking psychotropic medications was nearly the same as the level of the 10 patients who stopped benzodiazepines a week or more before the urine collection: mean 4- SD = 16 4- 1 i vs. 16 4- 14. A multiple regression was calculated to control for possible effects of gender and age. The partial correlation coefficient for the relationship of NAG and benzodiazepine use was not significant (P = 0.57).
NAG levels of study patients were significantly associated, with 23 of 72 POMS items. The large number of comparisons performed should have produced a few significant associations by chance alone, but not as many as were found, namely 23. We did not make Bonferroni adjustments because the analyses were exploratory and no specific hypothesis was to be tested° Such_ a correction _could have been too restrictive and eliminated preliminary findings that may merit further investigation. Several of the mood states listed in Table 1 can be grouped into categories such as (1) hostility or irritability, (2) sadness, and (3) panic. In a study of bipolar patients, the severity of these same psychiatric symptoms or categories (plus several other symptoms) was significantly associated with NAG (Garvey and Noel, 1992). What might account for the association of NAG to the severity of certain mood symptoms? We have speculated that one possibility is that NAG may be associated with serotonin turnover (Garvey and Noel, 1992). Several of the symptoms or mood states associated with NAG in this study or the bipolar study (Garvey and Noel, 1992) may involve serotonin as a neurotransmitter: for example, anxiety (Kahn et al., 1991) and hostility (Copenhaver et al., 1978; Broderick and Lynch, 1982; Coccaro, 1989; Coccaro et al., 1989). The hypothesis that NAG could be associated with serotonin metabolism was supported in an investigation of ours that showed a significant relationship between urinary levels of 5-hydroxyindoleacetic acid (5-HIAA) and NAG in a selected group of anxiety patients (Garvey et al., 1995). We have offered other indirect support for the postulate that NAG may be associated with serotonin turnover (Garvey and Black, 11993). Our data and hypotheses are clearly preliminary and require further testing and verification. If future research were to show an association between urinary NAG and central nervous system serotonin activity, it could provide a simple test to monitor serotonin status. Serotonin function has most often been assessed by measuring the serotonin metabolite 5-HIAA in the cerebrospinal fluid (CSF). The CSF is obtained by a lumbar spinal ~ap, a procedure that requires time, involves
M.J. Garvey, R. Noyes, Jr. /Psychiatry Research 60 (1996) 185-190
some risk, and cannot be performed routinely. An assessment of serotonin status might someday be of value in the selection of an antidepressant for a particular patient or for follow-up of potentially suicidal patients (,~sberg et ~1., 1976; Roy et al., 1986; Nordstr6m et al., 1994). In summary, urinary NAG was significantly associated with the severity of several mood states (symptoms) in a subgroup of panic disorder patients. The severity of several of these same symptoms was associated with NAG in a previous study of bipolar patients. Acknowledgments Support for this study was provided by the Department of Veterans Affairs and the University of Iowa College of Medicine. References Alderman, M.H., Melcher, L•, Drayer, D.E. and Reidenberg, M.M. (1983) Ir~creased excretion of N-acetyl-beta-glucosaminidase in essential hypertension and its decline with antihypertensive therapy. N Engl J Med 309, 1213-1217. ,~sberg, M., Trfiskman, L. and Thor~n, P. (1976) 5-HIAA in the cerebrospinal fluid - - A suicide predictor? Arch Gen Psychiatry 33, 1193-1197. Ballenger, J.C., Burrows, G.D., DuPont, R.L., Jr., Lesser, I.M., Noyes, R., Jr., Pecknold, J.C,, Rifkin, A. and Swinson, R.P. (1988) Alprazolam in panic disorder and agoraphobia: results from a multicenter trial. I. Efficacy in short-term treatment. Arch Gen Psychiatry 45, 413-422. Broderick, P. and Lynch, V. (1982) Behavioral and biochemical changes induced by lithium and L-tryptophan in muricidal rats. Neuropharmacology 671, 671-679. Burry, H.C., Dieppe, P.A., Bresnihan, F.B. and Brown, C. (1976) Salicylates and renal function in rheumatoid arthritis. Br Med J !, 613-615. Coccaro, E.F. (1989) Central serotonin and impulsive aggression. Br J Psychiatry 155, 52-62. Coc~aro, E.F., Siever, L.J., Klar, H.M., Mauler, G., Cochrane, K., Cooper T.B., Mohs, R.C. and Davis, K.L. (1989) Serotonergic studies in patients with affective and personality disorders. Correlates with suicidal and impulsive aggressive behavior. Arch Gen Psychiatry 46, 587-599. Copenhavcr, J H, c.~.~^.~ R.L. and Carver, ~A ~ i ! o ' ~ Effect of serotonin on Y-maze retention and hippocampal protein synthesis in rats. Pharmacol Biochem Behav 8, 263-270. Dubach, A.C. and Schmidt, A. (1979) Diagnostic Significance of Enzymes and Protein in Urine. Hans Huber Publishers, Bern, Stuttgart, Vienna. Garvey, M.J. and Black, D. (1993) An association between the •
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