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Correlation of nocturnal penile tumescence and daytime affect intensity in depressed men
139
Psychiatry Research, 49: I39- I50 Elsevier
Correlation of Nocturnal Penile Tumescence Affect Intensity in Depressed Men
and Daytime
Eric A. Nofzinger, Robert M. Schwartz, Charles F. Reynolds III, Michael E. Thase, J. Richard Jennings, Ellen Frank, Amy L. Fasiczka, Gregory L. Garamoni, and David J. Kupfer Received
November
19, 1992; revised version received April 16, 1993; accepted July 2, 1993.
Abstract. Although depressed patients have been shown to have diminished nocturnal penile tumescence (NPT), there remains considerable variability of NPT in depression. We hypothesized that affective experience during the day accounts for some of this variability. Forty-five depressed men had assessments of affect intensity and affect balance, NPT, and daytime sexual function, both before and after treatment with Beck’s cognitive behavior therapy (CBT). Forty-
three normal control subjects were studied for comparison. Daytime affect intensity in depressed men, but not in control subjects, correlated significantly and positively with measures of NPT duration and rigidity both before and after treatment, regardless of the adequacy of daytime sexual function. When the effect of daytime affect on REM activity was controlled, the observed correlations became nonsignificant at pretreatment, but remained significant at posttreatment. Neuropharmacologically mediated changes in arousal responsivity associated with depression may underlie the observed relation between daytime affect intensity, rapid eye movement activity, and NPT. Key Words.
Affective disorder,
sleep, sexual function,
cognitive
behavior
therapy. Depressed men have been shown to have diminished nocturnal penile tumescence (NPT) (Roose et al., 1982; Thase et al., 1987, 1988, 1992; Nofzinger et al., 19936). Still there remains considerable variability in NPT between depressed men, with most (roughly 70%) having normal NPT studies. Due to this variability, we asked if there are clinical correlates of NPT in depressed men that could account for betweensubject variability. Identification of such correlates might enhance the diagnostic interpretation of the NPT study by alerting the clinician to sources of variability that that a man has organogenic might yield a false-positive study (i.e., concluding impotence when the physiological capabilities for sexual function are intact). Previous findings in sleep research in normal subjects and depressed patients and in research describing affective processing in depression suggested that the
Eric A. Nofzinger, M.D., is Assistant Professor; Robert M. Schwartz, Ph.D., is adjunct Assistant Professor; Charles F. Reynolds III, M.D., is Professor; Michael E. Thase, M.D., is Associate Professor; J. Richard Jennings, Ph.D., is Professor; Ellen Frank, Ph.D., is Professor; Amy L. Fasiczka, B.A., is research associate; Gregory L. Garamoni, Ph.D., was project coordinator; and David J. Kupfer, M.D., is Professor and Chairman, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA. (Reprint requests to Dr. E.A. Nofzinger, Western Psychiatric Institute and Clinic, 3811 O’Hara St., Pittsburgh, PA 15213-2593, USA.) 0165-1781/93/$06.00
@ 1993 Elsevier Scientific
Publishers
Ireland
Ltd
140
identification of a clinical correlate of NPT in depressed men may come from an exploration of measures of daytime affect. A relation between one’s daytime experiences and sleep at night has long been recognized. Psychological theories suggest that one of the prominent functions of sleep, especially rapid eye movement (REM) sleep, is the regulation of mood by processing salient emotional experiences from the day (Breger, 1967; Cartwright, 1991; Kramer, in press). NPT is closely associated with REM sleep (Fisher et al., 1965), and previous work has shown that emotional aspects of a dream report are related to fluctuations in the amplitude of the sleep-related tumescence (Karacan et al., 1966). We have recently reported that affect intensity during the day is significantly and positively correlated with phasic REM sleep measures at night (Nofzinger et al., in press 6). Disturbances in affective processing (such as negative affect balance) have been well documented in depressed patients (Schwartz and Garamoni, 1986; Garamoni et al. 1991, 1992) as have alterations in EEG sleep (Buysse and Nofzinger, 1984). Given these relations, we hypothesized that the affective experience of depressed patients during the day would be related to the variability in NPT seen in depressed patients (both tumescence duration and penile rigidity during NPT). To test this hypothesis, we measured several dimensions of affect (Diener and Emmons, 1984; Schwartz and Garamoni, 1986; Larsen and Diener, 1987; Garamoni et al., 1991, 1992; Nofzinger et al., in press 6) in depressed men who were being treated in cognitive behavior therapy (CBT) and then correlated measures of affect with measures of NPT both before and after treatment. A healthy normal control group was studied at one time point for comparison.
Methods Study Design. The current study is an extension of our ongoing efforts to define electroencephalographic (EEG) sleep, sexual function, and NPT in depressed men (Thase et al., 1987, 1988, 1992; Nofzinger et al., 1993b). To enter the protocol, men between the ages of 20 and 60 requesting treatment at Western Psychiatric Institute and Clinic were required to have a current diagnosis of major depression according to Research Diagnostic Criteria (RDC) on the basis of an interview with the Schedule for Affective Disorders and 1978). Nonendogenous, endogenous, melancholic Schizophrenia (Endicott and Spitzer, (DSM-III-R criteria) (American Psychiatric Association, 1987), primary and secondary, nonbipolar, and recurrent unipolar RDC subtypes were eligible. Patients were required to have a minimum score of 15 of the first 17 items of the Hamilton Rating Scale for Depression (HRSD; Hamilton, 1960), sustained on repeated administration over the 2 weeks of the drug-free observation period, before sleep studies. During the same period, a score > 17 was required on the Beck Depression Inventory (BDI; Beck et al., 1961). Subjects who could not remain drug or alcohol free during the study were excluded. Subjects were also excluded if they met RDC for schizophrenia, schizoaffective disorder, or psychotic subtype of major depression or bipolar depression. During the 2-week drug-free period, patients were screened with a physical examination and laboratory studies for medical disorders that might confound sleep or NPT studies. These disorders included diabetes mellitus, hypertension (blood pressure 2 140/90 on repeated testing), cardiovascular, cerebrovascular, or peripheral vascular disease, urologic disease, previous lower back or pelvic surgery, and endocrinopathies. After a 2week psychotropic-drug-free interval, subjects were reexamined with respect to severity of depression, and all-night sleep EEG and NPT studies were performed. All subjects then were treated with CBT by therapists who had no knowledge about the results of baseline sleep and NPT findings. Patients received a maximum course of 20 fifty-minute CBT sessions
141
conducted over a 16-week acute treatment period. Remission was defined by an HRSD score < 7 over 4 consecutive weeks by the end of the treatment protocol. Nonremission was defined by a failure to achieve a stable reduction of HRSD scores to < 10 by the end of the 16-week treatment protocol. After completion of the CBT protocol, patients underwent a second series of sleep and NPT studies. Both before and after treatment, depressed subjects completed a lbday log documenting sexual interest and sexual activity, a Brief Sexual Function Questionnaire (BSFQ; Reynolds et al., 1988), and the Derogatis Sexual Function Inventory (DSFl; Derogatis and Melisanatos, 1979). These instruments have been described in detail in previous reports (Derogatis and Melisanatos, 1979; Reynolds et al., 1988; Nofzinger et al., 19936). Subjects. A total of 45 patients (out of 72 prescreened and 51 enrolled) completed both pretreatment and posttreatment EEG sleep and NPT studies. Six additional patients were enrolled but did not complete the study (3 withdrew, 1 dropped out for health reasons, and 2 were dropped from the study because of failure to abstain from alcohol or recreational drug use). Of the 45 patients who completed treatment, I9 (42%) were classified as remitted and I6 0 could not be classified as either (36%) as nonremitted. An additional 10 patients (229’) remitted or nonremitted according to our criteria and will be referred to as partially remitted. A healthy control group (n = 43) was recruited for comparison. Subjects were required to have HRSD depression scores < 6, and could have no history of psychiatric illness based on the Lifetime Version of the Schedule for Affective Disorders and Schizophrenia (Spitzer and Endicott, 1975) or medical conditions known to affect sleep or sexual function. Control subjects completed a 14-day drug- and alcohol-free period before undergoing EEG sleep and NPT evaluation. Assessment of Daytime Affect. All subjects completed the Affects Balance Scale (ABS; Derogatis, 1975), generally within 48-72 hours of sleep and NPT assessment, during the week before the pretreatment and posttreatment sleep and NPT assessments. The ABS is a list of 40 words that describe the way that people sometimes feel. Subjects are asked whether they have had any of these feelings during the past two weeks. A 5-point scale (0 = “never,“4 = “always”) is used to indicate the frequency of each emotion during the preceding 2 weeks. A factor analysis (Derogatis, 1982) on the ABS has revealed four negative dimensions (depression, anxiety, guilt, and hostility) as well as three positive dimensions (vigor, affection, and joy and contentment). When correlating the primary factors in a higher order analysis, Derogatis (1982) found two distinct superfactors consisting of positive and negative affect items. Variables from the ABS used in our analyses included: positive affects (sum of all positive dimension scores), negative affects (sum of all negative dimension scores), and statesof-mind (SOM) ratio (ratio of the positive affects score to the sum of the positive and negative affects scores) (Schwartz and Garamoni, 1986). EEG Sleep and NPT Protocol. All-night sleep EEG and NPT studies were performed over 4 consecutive nights in our sleep evaluation center using methods described in detail elsewhere (Reynolds et al., 1982; Kupfer and Thase, 1983). All records were recorded at a time constant of 0.3 and were scored by registered polysomnographic technologists according to the criteria of Rechtschaffen and Kales (1968) without knowledge of diagnosis. Urine samples were obtained before each night’s study to screen for drug or alcohol use. NPT recordings followed the methods described by Karacan et al. (1978). In brief, penile circumference changes were monitored by the use of two mercury-filled strain gauges, one placed at the base, and one at the tip of the penis. An episode of NPT was defined as an abrupt increase in base circumference to a > 3 mm change in pen deflection over a 60-second period and maintained for a least 5 minutes. On the third night of study, all subjects were briefly awakened at the point of maximal tumescence during each episode of NPT for estimation of fullness of erections and determination of penile buckling force. Reliability of visual estimation has been documented previously (Campbell et al., 1987). In our laboratory, test-
142 retest reliability for buckling force measures within subjects at identical estimates of erectile fullness is high (Pearson r = 0.89, n = 135, p < O.OOOl), although there is considerable instability of “maximum buckling force” between assessments (Nofzinger et al., 1993~2). The fourth night of study was used to collect data on penile arterial blood volume pulse (to be reported elsewhere). Variables analyzed from tumescence recordings included total tumescence time (minutes), total tumescence time divided by time spent asleep, total tumescence time divided by REM time, and maximum penile buckling force (grams force). Statistical Procedures. Spearman partial correlation coefficients (controlling for age) were used to evaluate the relationship between daytime affect and NPT variables. These were computed for depressed subjects both before and after treatment, and for control subjects at one time point. The correlation matrix consisted of four NPT variables (total tumescence time, total tumescence time/time spent asleep, total tunescence time/ REM time, and maximum buckling force) correlated with four affect variables (positive affect, negative affect, SOM ratio, and affect intensity). We used a Bonferroni adjustment of a = 0.05/S = 0.006 (four tumescence variables and four affect variables) to control for type-1 error inflation. All EEG sleep variables and tumescence variables (except maximum buckling force) were taken from the second night of recording, since the first night is an adaptation night and during the third night subjects are awakened artificially for penile visual inspection. Maximum buckling force measures are taken from the third night of recording. Due to the possibility that the influence of daytime affective experience on NPT variables may be mediated by the previously observed correlation between daytime affect intensity and REM activity (Nofzinger et al., in press b), we performed partial correlational analyses controlling for both age and possible REM activity effects. Student’s t tests were used to compare daytime sexual function variables for subgroups of depressed patients at posttreatment, stratified by level of positive affect intensity. A series of t tests were done on NPT, affect, and sleep measures. Group t tests compared the control subjects with the depressed patients at both pretreatment and posttreatment. Paired t tests compared the depressed patients at pretreatment and posttreatment.
Results clinical data for the subjects. Table 2 presents NPT variables, and selected EEG sleep variables for normal healthy control subjects and for depressed subjects at pretreatment and posttreatment. The results of these analyses have been described in detail in previous reports (Garamoni et al., 1992; Nofzinger et al., 19936, in pressa, in press b; Thase et al., submitted). Table 3 presents correlations between daytime affect measures and NPT variables for control subjects, and for depressed subjects at pretreatment and posttreatment. For control subjects there were no significant correlations between measures of affect and NPT variables. For depressed subjects, significant and positive correlations were observed between measures of affect intensity and NPT measures at both pretreatment and posttreatment. Further, in depressed subjects, the intensity of negative affect at pretreatment, as well as the intensity of positive affect at posttreatment, also correlated significantly and positively with NPT variables. Fig. 1 shows a scatterplot of the correlation between pretreatment total tumescence time/time spent asleep X pretreatment affect intensity. To determine if more intense positive affect was related to improved daytime sexual function, we ranked and divided our depressed subjects based on intensity of positive affect at posttreatment. We chose this time point to maximize the potential Table
1 presents
descriptive
data
demographic
for affect
and
measures,
143
Table 1. Demographic and clinical data for 45 depressed and 43 control men Depressed
Controls
(n = 45)
(n= 43) P
Mean
SD
Mean
SD
torx2
39.1
10.6
37.4
11.7
0.72’
-
15.8
2.6
16.3
2.0
1.01’
-
0.0a2
-
Demographics Age (yr) Education
(yr)
33122
Partner status (yes/no) Clinical
27116
data
Number
of previous
episodes
0.9
2.0
19.4
3.9
52.6
6.5
25.4
8.9
Duration of current episode Median
26.0
Range
3-260
Recurrent (yes/no) Endogenous
2123
(yes/no)
Intermittent (yes/no)
3817 32113
Hamilton Rating Scale for Depression score before cognitive behavior therapy Global Assessment
Scale score
before cognitive behavior therapy Beck Depression
Inventory score
before cognitive behavior therapy
1.Student’s t test. 2. x2 for contingency
tables.
in daytime sexual function among our depressed men, since 42% of them had remitted from depression by that time. A t test comparing those depressed patients who ranked in the top third (n = 15) with those depressed patients who ranked in the bottom third (n = 14) on the scale of positive affect intensity showed no significant differences in reported daytime sexual activity and interest as measured by the daily sexual function log and the BSFQ. We asked whether the significant correlations between tumescence and affect measures were simply an epiphenomenon of the significant correlations between phasic REM sleep and affect measures reported elsewhere (Nofzinger et al., in press). To answer this question, we repeated correlations between affect measures and NPT measures after controlling for both age and REM activity using Spearman partial correlation coefficients (Table 3b). After the effects of REM activity and age on NPT variables had been controlled for, the correlations between affect intensity and NPT variables were no longer statistically significant at pretreatment, with the exception of maximum buckling force X affect intensity. At posttreatment, however, the partial correlations between all NPT measures and affect intensity remained significant. Similarly, the partial correlations between positive affect and NPT measures remained significant at posttreatment.
variability
144
Table 2. Affect, NPT, and EEG sleep variables for control subjects and depressed patients before and after cognitive behavior therapy Depressed
Controls
(Cl
Pre-CBT
Post-CBT
(n = 43)
(Dl)
(D2)
Mean Affect
(n = 45)
SD
Mean
SD
Mean
SD
Paired
Group t test
t
C-D1
C-D2
t1
t2
test Dl-D2
t3
variables
Positive
51.83
9.94
22.18
11.59
33.47
17.07
12.7’
6.2’
4.77
Negative
14.37
7.17
46.02
12.28
29.24
15.15
-14.8’
-5.9’
-6.54
Ratio Intensity
0.79
0.10
0.32
0.15
0.52
0.23
16.7’
6.9’
5.77
66.10
10.71
68.20
11.90
62.71
16.39
-0.9
1.1
-2.34
122.95
55.32
98.73
48.74
99.71
42.35
2.24
2.24
0.1
0.31
0.15
0.26
0.12
0.26
0.10
1.8
1.94
-0.0
NPT variables Total tumescence
time
Total tumescence
time/
time spent asleep Total tumescence
time/
REM time Maximum buckling force
1.60
0.91
1.06
0.41
1.09
0.53
3.25
3.5”
-0.3
775.23
416.65
482.17
367.72
394.33
280.63
3.56
5.07
-1.5
0.9
EEG sleep variables Sleep efficiency8
89.82
7.64
89.17
7.94
90.22
6.67
-0.5
0.3
REM time
83.19
25.56
92.76
24.20
95.51
25.48
-1.8
-2.34
0.7
REM %
20.89
5.68
24.36
4.55
24.81
4.73
-3.25
-3.5@
0.5
REM latency8
84.75
40.12
60.24
16.99
63.67
23.62
3.86
REM activity8
108.78
64.11
147.04
66.29
126.96
60.52
-3.04
-1.6
-2.34
REM densin/*
1.32
0.52
1.59
0.62
1.32
0.46
-2.85
-0.5
-3.55
3.05
0.8
Note. NPT = nocturnal penile tumescence. EEG = electroencephalographic. CBT = cognitive behavior therapy. REM = rapid eye movement sleep period. 1. Group t test: controls vs. depressed pre-CBT. 2. Group t test: controls vs. depressed post-CBT. 3. Paired t test: depressed pre- vs. post-CBT. 4. p < 0.05. 5. p < 0.01. 6. p < 0.001. 7. p < 0.0001. 8. Sleep efficiency transformed to LOG (lOO-SE+l). square root
REM latency, REM activity, and REM density transformed to
Discussion The current data suggest that the daytime affective or emotional experience of a depressed man correlates modestly with NPT, with measures of daytime affect intensity accounting for 9-1570 of variance in NPT measures. In our depressed sample, the affect variables including affect intensity, negative affect, and positive affect were all significantly and positively correlated with NPT variables. After the previously reported effect of affect intensity on phasic REM sleep had been between most NPT controlled for (Nofzinger et al., in press b), the correlation variables and affect intensity was no longer significant at pretreatment but remained
145
Table 3a. Correlations1 between affect measures* and nocturnal penile tumescence variables for control subjects and depressed patients before and after cognitive behavior therapy (CBT) Depressed patients (n= 45)
Control subjects (n = 43)
Pre-CBT
Post-CBT
Pos Neg Ratio lnten Pos Neg Ratio lnten Pos Nag Ratio lnten P
P
P
P
P
P
P
P
P
-0.11
-0.16
0.07
0.293 -0.07
0.3Y
0.363 0.01
0.24
0.3g4
-0.09
0.08
-0.08
-0.11
0.03
0.333 -0.11
0.363
0.2g3 0.04
0.18
0.374
time -0.03
0.09
-0.09
0.03
0.01
0.22
-0.08
0.25
0.343-0.1 1
0.304
0.27
-0.345 0.13
-0.22
-0.25
0.11
0.20
-0.04
0.313
0.19
0.05
0.313
time/
time spent asleep time/
rapid eye movement buckling
P
0.08
time
Total tumescence
Maximum
P
-0.16
Total tumescence
Total tumescence
P
force
0.08
1. Spearman rank correlations partialed for age. 2. Pos = positive affects; Neg = negative affects: Ratio = states of mind ratio; lnten = affect intensity. 3. p < 0.05. 4. p < 0.01 (remained significant after Bonferroni correction). 5. When one observation is removed, r = -0.29, p < 0.06.
Table 36. Correlations1 between affect measures*and nocturnal penile tumescence variables for depressed patients before and after cognitive behavior therapy (CBT) Depressed patients (n = 45) Pre-CBT
Post-CBT
Pos Neg Ratio lnten Pos Neg Ratio lnten PPPPPPPP Total
tumescence
Total tumescence
time
time spent asleep Total tumescence
buckling
0.23
-0.11
0.23
0.333-0.04
0.23
0.333
-0.04
0.28
-0.14
0.26
0.28
0.18
0.363
0.02
time/
rapid eye movement Maximum
-0.00
time/
time
force
-0.00
0.21
-0.08
0.24
0.4i4-0.07
0.323
0.373
0.10
0.18
-0.04
0.303
0.18
0.04
0.303
0.06
1. Spearman rank correlations partialed for age and rapid eye movement activity. 2. Pos = positive affects; Neg = negative affects; Ratio = states of mind ratio; lnten = affect intensity 3. p < 0.05. 4. p < 0.006 (remained significant after Bonferroni correction).
significant at posttreatment. These findings were not related to waking sexual function, however, and were not seen in healthy control subjects. In the current study, the relation between daytime affect and NPT variables was partly a function of “affect intensity.” Specifically, the amount of NPT appeared to be related to the intensity of the predominant affect experienced by depressed patients. Before treatment, when negative affect prevailed (Garamoni et al., 1992), NPT was significantly correlated with negative affect. After treatment, when positive affect prevailed (Garamoni et al., 1992) NPT was significantly correlated with
146
Fig. 1. Scatterplot of correlation between pretreatment total tumescence time/time spent asleep X pretreatment affect intensity 0.‘ : 1 j
m
5
n 0,s
::
\$
s.mA 0.4
m
n
E o.,-
r=0,35
p < .02
5
n
f !I h
m 04 40
50
l
00
Pm-Troctment
n=45
n
70
ABS
00
so
1
100
lntomity Scare
ABS = Affects Balance Scale.
positive affect. Our impression is that the seemingly different correlations between positive and negative affect and NPT measures (from pretreatment to posttreatment) can be viewed as a function of the underlying relation between affect intensity (regardless of polarity) and NPT, allowing for a shift in the predominant affect from pretreatment to posttreatment (Garamoni et al., 1992). After the effect of affect intensity on REM activity was controlled for, the correlation between affect and NPT measures become nonsignificant at pretreatment but remained significant at posttreatment. Also, phasic REM sleep and NPT measures were correlated at pretreatment but not at posttreatment. This suggests that at pretreatment there may be a common psychobiological mechanism that relates daytime affect intensity to both phasic REM sleep and NPT measures. NPT measures at pretreatment may reflect the phasic bursts of activity noted in the autonomic nervous system concurrent with the phasic bursts of eye movement activity in REM sleep. At posttreatment, phasic REM sleep returned to normal levels in our depressed patients (Table 2). At this time the correlation between affect intensity and NPT measures can be detected even after controlling for the effect of affect intensity on phasic REM sleep, While the physiological mechanisms for the relation between phasic and tonic REM sleep and sleep-related penile tumescence have not been clearly delineated, the significant correlation between affect intensity and NPT at posttreatment, even after the effect of affect intensity on REM activity is controlled for, suggests that the relation between daytime affect and NPT is not entirely mediated by alterations in phasic REM sleep.
147 How can we explain the observed relation between affect intensity and NPT? Previous research on “affect intensity” comes from studies of personality. Affect intensity is thought to reflect how individuals vary in their degree of emotional responsiveness (Larsen and Diener, 1987). Affect intensity is seen as a personality trait such that individuals with high affect intensity experience both positive and negative affects to greater degrees than do individuals with lower affect intensity. Research on arousal suggests that individuals with intense affects have relatively enhanced arousal responses to stimuli (Eysenck, 1967; Larsen and Zarate, 1991). Research on the neuropharmacology of sexual behavior suggests that dopaminergic and adrenergic neurotransmitter systems are involved in penile erection (for review, see Segraves, 1989). Augmentation of sexual behavior by central dopamine facilitation and by lowering of central serotonergic activity has also been reported. Perhaps NPT measures and affect intensity are related through common neurotransmitter systems that mediate arousal responsivity. While NPT variables measuring the duration of tumescence correlated with affect variables, the NPT variable “maximum buckling force” also correlated significantly and positively with affect intensity at both pretreatment and posttreatment for depressed patients. These correlations remained significant even after the effect of affect intensity on REM activity reported elsewhere (Nofzinger et al., in pressb) had been controlled for. This suggests that the relation between affect intensity and erectile function is not entirely dependent on measures of tumescence time which are related to the duration of REM sleep. This observation may help to explain some of the instability of “maximum buckling force” in NPT studies (Nofzinger et al., 1993~). While it is possible that the significance of some of the correlations reported represents type-1 error, similar effects were detected at two separate time points for the depressed subjects, suggesting a relation that is stable over time. In the current study, we have suggested a relation between NPT and affect intensity in depressed men. It remains to be seen whether this relation is specific to the state of depression, or whether other groups exhibit similar relations between emotions or affects during the day and tumescence during sleep. We did not observe the same relation in healthy control subjects. It is certainly possible, and likely, that other psychiatric groups may exhibit similar effects of daytime affect intensity on NPT. Schizophrenic patients, for example, have well-documented abnormalities in EEG sleep (Keshavan et al., 1990; Benca et al., 1992; Tandon et al., 1992; Nofzinger et al., 1993~). If the salient variable is low affect intensity (flattening of affect), then schizophrenic patients exhibiting predominantly negative symptoms of schizophrenia may be at in.creased risk for reductions in NPT. In summary, the results of the current study suggest that NPT studies in depressed patients correlate modestly with their daytime emotional experience. Specifically, in depressed men, some of the between-subject variability in NPT is related to the level of emotional responsiveness, or affect intensity, irrespective of daytime sexual function. It remains a matter for further study as to whether this relation is specific to depressed men or whether it may also be present in other patient groups.
148 Acknowledgments. The research reported herein was supported in part by grants MH16804, MH-40023, MH-30915, and MH-00295 from the National Institute of Mental Health. The authors wish to acknowledge the constructive comments of the anonymous reviewers of Psychiatry Research.
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149 Keshavan, M.S.; Reynolds, C.F.; and Kupfer, D.J. Electroencephalographic sleep in schizophrenia: A critical review. Comprehensive Psychiatry, 30:34-47, 1990. Kramer, M. The selective mood regulatory function of dreaming: An update and revision. In: Moffitt, A.R.; Kramer, M.; and Hoffman, R.F., eds. The Function of Dreaming. Albany, NY: State University of New York Press, in press. Kupfer, D.J., and Thase, M.E. The use of the sleep laboratory in the diagnosis of affective disorder. Psychiatric Clinics of North America, 6:3-25, 1983. Larsen, R.J., and Diener, E. Affect intensity as an individual difference characteristic: A review. Journal of Research in Personality, 21: l-39, 1987. Larsen, R.J., and Zarate, M.A. Extending reducer/augmenter theory into the emotion domain: The role of affect in regulating stimulation level. Personality and Individual Differences, 12:713-723, 1991. Nofzinger, E.A.; Buysse, D.J.; Reynolds, C.F. III; and Kupfer, D.J. Sleep disorders related to another mental disorder (non-substance/primary): A DSM-IV literature review. Journal of Clinical Psychiatry, in press a. Nofzinger, E.A.; Fasiczka, A.L.; Thase, M.E.; Reynolds, C.F. III; Frank, E.; Jennings, J.R.; Garamoni, G.L.; and Kupfer, D.J. Are buckling force measurements reliable in NPT studies? Sleep, 16:156-162, 1993a. Nofzinger, E.A.; Schwartz, R.M.; Reynolds, C.F. III; Thase, M.E.; Jennings, J.R.; Frank, E.; Fasiczka, A.L.; Garamoni, G.L.; and Kupfer, D.J. Correlation of affect intensity and phasic REM sleep in depressed men. Journal of Consulting and Clinical Psychology, in press b. Nofzinger, E.A.; Thase, M.E.; Reynolds, C.F. III; Frank, E.; Jennings, J.K.; Garamom, G.L.; Fasiczka, A.L.; and Kupfer, D.J. Sexual function in depressed men: Assessment by self-report behavioral, and nocturnal penile tumescence measures before and after treatment with cognitive behavior therapy. Archives of General Psychiatry, 50:24-30, 19936. Rechtschaffen, A.R., and Kales, A. A Manual of Standardized Terminology, Techniques, and Scoring System for Sleep Stages of Human Subjects. (National Institutes of Health Publication 204) Washington, DC: Superintendent of Documents, U.S. Government Printing Office, 1968. Reynolds, C.F. III; Frank, E.; Thase, M.E.; Houck, P.R.; Jennings, J.R.; Howell, J.R.; Lilienfeld, S.O.; and Kupfer, D.J. Assessment of sexual function in depressed, impotent and healthy men: Factor analysis of a brief sexual function questionnaire for men. Psychiatry Research, 24:231-250, 1988. Reynolds, C.F. III; Kupfer, D.J.; Coble, P.A.; and Shaw, D. Depressive patients in the sleep laboratory. In: Guilleminault, C., ed. Sleeping and Waking Disorders: Indications and Techniques. Reading, MA: Addison-Wesley, 1982. Roose, S.P.; Glassman, A.H.; Walsh, B.T.; and Cullen, K. Reversible loss of nocturnal penile tumescence during depression: A preliminary report. Neuropsychobiology, 8:284-288, 1982. Schwartz, R.M., and Garamoni, G.L. A stuctural model of positive and negative states of mind: Asymmetry for the internal dialogue. In: Kendall, P.C., ed. Advances in CognitiveBehavioral Research and Therapy. Vol. 5. New York: Academic Press, 1986. pp. l-62. Segraves, R.T. Effects of psychotropic drugs on human erection and ejaculation. Archives of General Psychiatry, 46~275-284, 1989.
150
Shaw, B.F. Specification of the training and evaluation of cognitive therapists for outcome studies. In: Williams, J.B.W., and Spitzer, R.L., eds. Psychotheruphy Research: Where Are We and Where Should We Go? New York: Guilford Press, 1984. Spitzer, R.L., and Endicott, J. Schedule for Affective Disorders and SchizophreniaLifetime Version. New York: New York State Psychiatric Institute, 1975. Tandon, R.; Shipley, J.E.; Taylor, S.; Greden, J.F.; Eiser, A.; DeQuardo, J.; and Goodson, J. Electroencephalographic sleep abnormalities in schizophrenia: Relationship to positive/ negative symptoms and prior neuroleptic treatment. Archives of General Psychiatry, 49:185-194, 1992. Thase, M.E.; Reynolds, C.F. III; Frank, E.; Jennings, J.R.; Fasiczka, A.L.; Garamoni, G.; Nofzinger, E.A.; and Kupfer, D.J. Electroencephalographic sleep in depressed men before and after treatment with cognitive behavior therapy. Submitted for publication. Thase, M.E.; Reyno1dqC.F. III; Glanz, L.N.; Jennings, J.R.; Sewitch, D.E.; Kupfer, D.J.; and Frank, E. Nocturnal penile tumescence in depressed men. American Journal of Psychiatry, 144:89-92, 1987. Thase, M.E.; Reynolds, C.F. III; Jennings, J.R.; Frank, E.; Garamoni, G.; Nofzinger, E.A.; Yeager, A.; and Kupfer, D.J. Diminished nocturnal penile tumescence in depression: A replication study. Biological Psychiatry, 31:1136-l 142, 1992. Thase, M.E.; Reynolds, C.F. III; Jennings, J.R.; Frank, E.; Howell, J.R.; Houck, P.R.; Berman, S.; and Kupfer, D.J. Nocturnal penile tumescence is diminished in depressed men. Biological Psychiatry, 24:33-46, 1988.
Psychiatry Research, 49: I39- I50 Elsevier
Correlation of Nocturnal Penile Tumescence Affect Intensity in Depressed Men
and Daytime
Eric A. Nofzinger, Robert M. Schwartz, Charles F. Reynolds III, Michael E. Thase, J. Richard Jennings, Ellen Frank, Amy L. Fasiczka, Gregory L. Garamoni, and David J. Kupfer Received
November
19, 1992; revised version received April 16, 1993; accepted July 2, 1993.
Abstract. Although depressed patients have been shown to have diminished nocturnal penile tumescence (NPT), there remains considerable variability of NPT in depression. We hypothesized that affective experience during the day accounts for some of this variability. Forty-five depressed men had assessments of affect intensity and affect balance, NPT, and daytime sexual function, both before and after treatment with Beck’s cognitive behavior therapy (CBT). Forty-
three normal control subjects were studied for comparison. Daytime affect intensity in depressed men, but not in control subjects, correlated significantly and positively with measures of NPT duration and rigidity both before and after treatment, regardless of the adequacy of daytime sexual function. When the effect of daytime affect on REM activity was controlled, the observed correlations became nonsignificant at pretreatment, but remained significant at posttreatment. Neuropharmacologically mediated changes in arousal responsivity associated with depression may underlie the observed relation between daytime affect intensity, rapid eye movement activity, and NPT. Key Words.
Affective disorder,
sleep, sexual function,
cognitive
behavior
therapy. Depressed men have been shown to have diminished nocturnal penile tumescence (NPT) (Roose et al., 1982; Thase et al., 1987, 1988, 1992; Nofzinger et al., 19936). Still there remains considerable variability in NPT between depressed men, with most (roughly 70%) having normal NPT studies. Due to this variability, we asked if there are clinical correlates of NPT in depressed men that could account for betweensubject variability. Identification of such correlates might enhance the diagnostic interpretation of the NPT study by alerting the clinician to sources of variability that that a man has organogenic might yield a false-positive study (i.e., concluding impotence when the physiological capabilities for sexual function are intact). Previous findings in sleep research in normal subjects and depressed patients and in research describing affective processing in depression suggested that the
Eric A. Nofzinger, M.D., is Assistant Professor; Robert M. Schwartz, Ph.D., is adjunct Assistant Professor; Charles F. Reynolds III, M.D., is Professor; Michael E. Thase, M.D., is Associate Professor; J. Richard Jennings, Ph.D., is Professor; Ellen Frank, Ph.D., is Professor; Amy L. Fasiczka, B.A., is research associate; Gregory L. Garamoni, Ph.D., was project coordinator; and David J. Kupfer, M.D., is Professor and Chairman, Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA. (Reprint requests to Dr. E.A. Nofzinger, Western Psychiatric Institute and Clinic, 3811 O’Hara St., Pittsburgh, PA 15213-2593, USA.) 0165-1781/93/$06.00
@ 1993 Elsevier Scientific
Publishers
Ireland
Ltd
140
identification of a clinical correlate of NPT in depressed men may come from an exploration of measures of daytime affect. A relation between one’s daytime experiences and sleep at night has long been recognized. Psychological theories suggest that one of the prominent functions of sleep, especially rapid eye movement (REM) sleep, is the regulation of mood by processing salient emotional experiences from the day (Breger, 1967; Cartwright, 1991; Kramer, in press). NPT is closely associated with REM sleep (Fisher et al., 1965), and previous work has shown that emotional aspects of a dream report are related to fluctuations in the amplitude of the sleep-related tumescence (Karacan et al., 1966). We have recently reported that affect intensity during the day is significantly and positively correlated with phasic REM sleep measures at night (Nofzinger et al., in press 6). Disturbances in affective processing (such as negative affect balance) have been well documented in depressed patients (Schwartz and Garamoni, 1986; Garamoni et al. 1991, 1992) as have alterations in EEG sleep (Buysse and Nofzinger, 1984). Given these relations, we hypothesized that the affective experience of depressed patients during the day would be related to the variability in NPT seen in depressed patients (both tumescence duration and penile rigidity during NPT). To test this hypothesis, we measured several dimensions of affect (Diener and Emmons, 1984; Schwartz and Garamoni, 1986; Larsen and Diener, 1987; Garamoni et al., 1991, 1992; Nofzinger et al., in press 6) in depressed men who were being treated in cognitive behavior therapy (CBT) and then correlated measures of affect with measures of NPT both before and after treatment. A healthy normal control group was studied at one time point for comparison.
Methods Study Design. The current study is an extension of our ongoing efforts to define electroencephalographic (EEG) sleep, sexual function, and NPT in depressed men (Thase et al., 1987, 1988, 1992; Nofzinger et al., 1993b). To enter the protocol, men between the ages of 20 and 60 requesting treatment at Western Psychiatric Institute and Clinic were required to have a current diagnosis of major depression according to Research Diagnostic Criteria (RDC) on the basis of an interview with the Schedule for Affective Disorders and 1978). Nonendogenous, endogenous, melancholic Schizophrenia (Endicott and Spitzer, (DSM-III-R criteria) (American Psychiatric Association, 1987), primary and secondary, nonbipolar, and recurrent unipolar RDC subtypes were eligible. Patients were required to have a minimum score of 15 of the first 17 items of the Hamilton Rating Scale for Depression (HRSD; Hamilton, 1960), sustained on repeated administration over the 2 weeks of the drug-free observation period, before sleep studies. During the same period, a score > 17 was required on the Beck Depression Inventory (BDI; Beck et al., 1961). Subjects who could not remain drug or alcohol free during the study were excluded. Subjects were also excluded if they met RDC for schizophrenia, schizoaffective disorder, or psychotic subtype of major depression or bipolar depression. During the 2-week drug-free period, patients were screened with a physical examination and laboratory studies for medical disorders that might confound sleep or NPT studies. These disorders included diabetes mellitus, hypertension (blood pressure 2 140/90 on repeated testing), cardiovascular, cerebrovascular, or peripheral vascular disease, urologic disease, previous lower back or pelvic surgery, and endocrinopathies. After a 2week psychotropic-drug-free interval, subjects were reexamined with respect to severity of depression, and all-night sleep EEG and NPT studies were performed. All subjects then were treated with CBT by therapists who had no knowledge about the results of baseline sleep and NPT findings. Patients received a maximum course of 20 fifty-minute CBT sessions
141
conducted over a 16-week acute treatment period. Remission was defined by an HRSD score < 7 over 4 consecutive weeks by the end of the treatment protocol. Nonremission was defined by a failure to achieve a stable reduction of HRSD scores to < 10 by the end of the 16-week treatment protocol. After completion of the CBT protocol, patients underwent a second series of sleep and NPT studies. Both before and after treatment, depressed subjects completed a lbday log documenting sexual interest and sexual activity, a Brief Sexual Function Questionnaire (BSFQ; Reynolds et al., 1988), and the Derogatis Sexual Function Inventory (DSFl; Derogatis and Melisanatos, 1979). These instruments have been described in detail in previous reports (Derogatis and Melisanatos, 1979; Reynolds et al., 1988; Nofzinger et al., 19936). Subjects. A total of 45 patients (out of 72 prescreened and 51 enrolled) completed both pretreatment and posttreatment EEG sleep and NPT studies. Six additional patients were enrolled but did not complete the study (3 withdrew, 1 dropped out for health reasons, and 2 were dropped from the study because of failure to abstain from alcohol or recreational drug use). Of the 45 patients who completed treatment, I9 (42%) were classified as remitted and I6 0 could not be classified as either (36%) as nonremitted. An additional 10 patients (229’) remitted or nonremitted according to our criteria and will be referred to as partially remitted. A healthy control group (n = 43) was recruited for comparison. Subjects were required to have HRSD depression scores < 6, and could have no history of psychiatric illness based on the Lifetime Version of the Schedule for Affective Disorders and Schizophrenia (Spitzer and Endicott, 1975) or medical conditions known to affect sleep or sexual function. Control subjects completed a 14-day drug- and alcohol-free period before undergoing EEG sleep and NPT evaluation. Assessment of Daytime Affect. All subjects completed the Affects Balance Scale (ABS; Derogatis, 1975), generally within 48-72 hours of sleep and NPT assessment, during the week before the pretreatment and posttreatment sleep and NPT assessments. The ABS is a list of 40 words that describe the way that people sometimes feel. Subjects are asked whether they have had any of these feelings during the past two weeks. A 5-point scale (0 = “never,“4 = “always”) is used to indicate the frequency of each emotion during the preceding 2 weeks. A factor analysis (Derogatis, 1982) on the ABS has revealed four negative dimensions (depression, anxiety, guilt, and hostility) as well as three positive dimensions (vigor, affection, and joy and contentment). When correlating the primary factors in a higher order analysis, Derogatis (1982) found two distinct superfactors consisting of positive and negative affect items. Variables from the ABS used in our analyses included: positive affects (sum of all positive dimension scores), negative affects (sum of all negative dimension scores), and statesof-mind (SOM) ratio (ratio of the positive affects score to the sum of the positive and negative affects scores) (Schwartz and Garamoni, 1986). EEG Sleep and NPT Protocol. All-night sleep EEG and NPT studies were performed over 4 consecutive nights in our sleep evaluation center using methods described in detail elsewhere (Reynolds et al., 1982; Kupfer and Thase, 1983). All records were recorded at a time constant of 0.3 and were scored by registered polysomnographic technologists according to the criteria of Rechtschaffen and Kales (1968) without knowledge of diagnosis. Urine samples were obtained before each night’s study to screen for drug or alcohol use. NPT recordings followed the methods described by Karacan et al. (1978). In brief, penile circumference changes were monitored by the use of two mercury-filled strain gauges, one placed at the base, and one at the tip of the penis. An episode of NPT was defined as an abrupt increase in base circumference to a > 3 mm change in pen deflection over a 60-second period and maintained for a least 5 minutes. On the third night of study, all subjects were briefly awakened at the point of maximal tumescence during each episode of NPT for estimation of fullness of erections and determination of penile buckling force. Reliability of visual estimation has been documented previously (Campbell et al., 1987). In our laboratory, test-
142 retest reliability for buckling force measures within subjects at identical estimates of erectile fullness is high (Pearson r = 0.89, n = 135, p < O.OOOl), although there is considerable instability of “maximum buckling force” between assessments (Nofzinger et al., 1993~2). The fourth night of study was used to collect data on penile arterial blood volume pulse (to be reported elsewhere). Variables analyzed from tumescence recordings included total tumescence time (minutes), total tumescence time divided by time spent asleep, total tumescence time divided by REM time, and maximum penile buckling force (grams force). Statistical Procedures. Spearman partial correlation coefficients (controlling for age) were used to evaluate the relationship between daytime affect and NPT variables. These were computed for depressed subjects both before and after treatment, and for control subjects at one time point. The correlation matrix consisted of four NPT variables (total tumescence time, total tumescence time/time spent asleep, total tunescence time/ REM time, and maximum buckling force) correlated with four affect variables (positive affect, negative affect, SOM ratio, and affect intensity). We used a Bonferroni adjustment of a = 0.05/S = 0.006 (four tumescence variables and four affect variables) to control for type-1 error inflation. All EEG sleep variables and tumescence variables (except maximum buckling force) were taken from the second night of recording, since the first night is an adaptation night and during the third night subjects are awakened artificially for penile visual inspection. Maximum buckling force measures are taken from the third night of recording. Due to the possibility that the influence of daytime affective experience on NPT variables may be mediated by the previously observed correlation between daytime affect intensity and REM activity (Nofzinger et al., in press b), we performed partial correlational analyses controlling for both age and possible REM activity effects. Student’s t tests were used to compare daytime sexual function variables for subgroups of depressed patients at posttreatment, stratified by level of positive affect intensity. A series of t tests were done on NPT, affect, and sleep measures. Group t tests compared the control subjects with the depressed patients at both pretreatment and posttreatment. Paired t tests compared the depressed patients at pretreatment and posttreatment.
Results clinical data for the subjects. Table 2 presents NPT variables, and selected EEG sleep variables for normal healthy control subjects and for depressed subjects at pretreatment and posttreatment. The results of these analyses have been described in detail in previous reports (Garamoni et al., 1992; Nofzinger et al., 19936, in pressa, in press b; Thase et al., submitted). Table 3 presents correlations between daytime affect measures and NPT variables for control subjects, and for depressed subjects at pretreatment and posttreatment. For control subjects there were no significant correlations between measures of affect and NPT variables. For depressed subjects, significant and positive correlations were observed between measures of affect intensity and NPT measures at both pretreatment and posttreatment. Further, in depressed subjects, the intensity of negative affect at pretreatment, as well as the intensity of positive affect at posttreatment, also correlated significantly and positively with NPT variables. Fig. 1 shows a scatterplot of the correlation between pretreatment total tumescence time/time spent asleep X pretreatment affect intensity. To determine if more intense positive affect was related to improved daytime sexual function, we ranked and divided our depressed subjects based on intensity of positive affect at posttreatment. We chose this time point to maximize the potential Table
1 presents
descriptive
data
demographic
for affect
and
measures,
143
Table 1. Demographic and clinical data for 45 depressed and 43 control men Depressed
Controls
(n = 45)
(n= 43) P
Mean
SD
Mean
SD
torx2
39.1
10.6
37.4
11.7
0.72’
-
15.8
2.6
16.3
2.0
1.01’
-
0.0a2
-
Demographics Age (yr) Education
(yr)
33122
Partner status (yes/no) Clinical
27116
data
Number
of previous
episodes
0.9
2.0
19.4
3.9
52.6
6.5
25.4
8.9
Duration of current episode Median
26.0
Range
3-260
Recurrent (yes/no) Endogenous
2123
(yes/no)
Intermittent (yes/no)
3817 32113
Hamilton Rating Scale for Depression score before cognitive behavior therapy Global Assessment
Scale score
before cognitive behavior therapy Beck Depression
Inventory score
before cognitive behavior therapy
1.Student’s t test. 2. x2 for contingency
tables.
in daytime sexual function among our depressed men, since 42% of them had remitted from depression by that time. A t test comparing those depressed patients who ranked in the top third (n = 15) with those depressed patients who ranked in the bottom third (n = 14) on the scale of positive affect intensity showed no significant differences in reported daytime sexual activity and interest as measured by the daily sexual function log and the BSFQ. We asked whether the significant correlations between tumescence and affect measures were simply an epiphenomenon of the significant correlations between phasic REM sleep and affect measures reported elsewhere (Nofzinger et al., in press). To answer this question, we repeated correlations between affect measures and NPT measures after controlling for both age and REM activity using Spearman partial correlation coefficients (Table 3b). After the effects of REM activity and age on NPT variables had been controlled for, the correlations between affect intensity and NPT variables were no longer statistically significant at pretreatment, with the exception of maximum buckling force X affect intensity. At posttreatment, however, the partial correlations between all NPT measures and affect intensity remained significant. Similarly, the partial correlations between positive affect and NPT measures remained significant at posttreatment.
variability
144
Table 2. Affect, NPT, and EEG sleep variables for control subjects and depressed patients before and after cognitive behavior therapy Depressed
Controls
(Cl
Pre-CBT
Post-CBT
(n = 43)
(Dl)
(D2)
Mean Affect
(n = 45)
SD
Mean
SD
Mean
SD
Paired
Group t test
t
C-D1
C-D2
t1
t2
test Dl-D2
t3
variables
Positive
51.83
9.94
22.18
11.59
33.47
17.07
12.7’
6.2’
4.77
Negative
14.37
7.17
46.02
12.28
29.24
15.15
-14.8’
-5.9’
-6.54
Ratio Intensity
0.79
0.10
0.32
0.15
0.52
0.23
16.7’
6.9’
5.77
66.10
10.71
68.20
11.90
62.71
16.39
-0.9
1.1
-2.34
122.95
55.32
98.73
48.74
99.71
42.35
2.24
2.24
0.1
0.31
0.15
0.26
0.12
0.26
0.10
1.8
1.94
-0.0
NPT variables Total tumescence
time
Total tumescence
time/
time spent asleep Total tumescence
time/
REM time Maximum buckling force
1.60
0.91
1.06
0.41
1.09
0.53
3.25
3.5”
-0.3
775.23
416.65
482.17
367.72
394.33
280.63
3.56
5.07
-1.5
0.9
EEG sleep variables Sleep efficiency8
89.82
7.64
89.17
7.94
90.22
6.67
-0.5
0.3
REM time
83.19
25.56
92.76
24.20
95.51
25.48
-1.8
-2.34
0.7
REM %
20.89
5.68
24.36
4.55
24.81
4.73
-3.25
-3.5@
0.5
REM latency8
84.75
40.12
60.24
16.99
63.67
23.62
3.86
REM activity8
108.78
64.11
147.04
66.29
126.96
60.52
-3.04
-1.6
-2.34
REM densin/*
1.32
0.52
1.59
0.62
1.32
0.46
-2.85
-0.5
-3.55
3.05
0.8
Note. NPT = nocturnal penile tumescence. EEG = electroencephalographic. CBT = cognitive behavior therapy. REM = rapid eye movement sleep period. 1. Group t test: controls vs. depressed pre-CBT. 2. Group t test: controls vs. depressed post-CBT. 3. Paired t test: depressed pre- vs. post-CBT. 4. p < 0.05. 5. p < 0.01. 6. p < 0.001. 7. p < 0.0001. 8. Sleep efficiency transformed to LOG (lOO-SE+l). square root
REM latency, REM activity, and REM density transformed to
Discussion The current data suggest that the daytime affective or emotional experience of a depressed man correlates modestly with NPT, with measures of daytime affect intensity accounting for 9-1570 of variance in NPT measures. In our depressed sample, the affect variables including affect intensity, negative affect, and positive affect were all significantly and positively correlated with NPT variables. After the previously reported effect of affect intensity on phasic REM sleep had been between most NPT controlled for (Nofzinger et al., in press b), the correlation variables and affect intensity was no longer significant at pretreatment but remained
145
Table 3a. Correlations1 between affect measures* and nocturnal penile tumescence variables for control subjects and depressed patients before and after cognitive behavior therapy (CBT) Depressed patients (n= 45)
Control subjects (n = 43)
Pre-CBT
Post-CBT
Pos Neg Ratio lnten Pos Neg Ratio lnten Pos Nag Ratio lnten P
P
P
P
P
P
P
P
P
-0.11
-0.16
0.07
0.293 -0.07
0.3Y
0.363 0.01
0.24
0.3g4
-0.09
0.08
-0.08
-0.11
0.03
0.333 -0.11
0.363
0.2g3 0.04
0.18
0.374
time -0.03
0.09
-0.09
0.03
0.01
0.22
-0.08
0.25
0.343-0.1 1
0.304
0.27
-0.345 0.13
-0.22
-0.25
0.11
0.20
-0.04
0.313
0.19
0.05
0.313
time/
time spent asleep time/
rapid eye movement buckling
P
0.08
time
Total tumescence
Maximum
P
-0.16
Total tumescence
Total tumescence
P
force
0.08
1. Spearman rank correlations partialed for age. 2. Pos = positive affects; Neg = negative affects: Ratio = states of mind ratio; lnten = affect intensity. 3. p < 0.05. 4. p < 0.01 (remained significant after Bonferroni correction). 5. When one observation is removed, r = -0.29, p < 0.06.
Table 36. Correlations1 between affect measures*and nocturnal penile tumescence variables for depressed patients before and after cognitive behavior therapy (CBT) Depressed patients (n = 45) Pre-CBT
Post-CBT
Pos Neg Ratio lnten Pos Neg Ratio lnten PPPPPPPP Total
tumescence
Total tumescence
time
time spent asleep Total tumescence
buckling
0.23
-0.11
0.23
0.333-0.04
0.23
0.333
-0.04
0.28
-0.14
0.26
0.28
0.18
0.363
0.02
time/
rapid eye movement Maximum
-0.00
time/
time
force
-0.00
0.21
-0.08
0.24
0.4i4-0.07
0.323
0.373
0.10
0.18
-0.04
0.303
0.18
0.04
0.303
0.06
1. Spearman rank correlations partialed for age and rapid eye movement activity. 2. Pos = positive affects; Neg = negative affects; Ratio = states of mind ratio; lnten = affect intensity 3. p < 0.05. 4. p < 0.006 (remained significant after Bonferroni correction).
significant at posttreatment. These findings were not related to waking sexual function, however, and were not seen in healthy control subjects. In the current study, the relation between daytime affect and NPT variables was partly a function of “affect intensity.” Specifically, the amount of NPT appeared to be related to the intensity of the predominant affect experienced by depressed patients. Before treatment, when negative affect prevailed (Garamoni et al., 1992), NPT was significantly correlated with negative affect. After treatment, when positive affect prevailed (Garamoni et al., 1992) NPT was significantly correlated with
146
Fig. 1. Scatterplot of correlation between pretreatment total tumescence time/time spent asleep X pretreatment affect intensity 0.‘ : 1 j
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positive affect. Our impression is that the seemingly different correlations between positive and negative affect and NPT measures (from pretreatment to posttreatment) can be viewed as a function of the underlying relation between affect intensity (regardless of polarity) and NPT, allowing for a shift in the predominant affect from pretreatment to posttreatment (Garamoni et al., 1992). After the effect of affect intensity on REM activity was controlled for, the correlation between affect and NPT measures become nonsignificant at pretreatment but remained significant at posttreatment. Also, phasic REM sleep and NPT measures were correlated at pretreatment but not at posttreatment. This suggests that at pretreatment there may be a common psychobiological mechanism that relates daytime affect intensity to both phasic REM sleep and NPT measures. NPT measures at pretreatment may reflect the phasic bursts of activity noted in the autonomic nervous system concurrent with the phasic bursts of eye movement activity in REM sleep. At posttreatment, phasic REM sleep returned to normal levels in our depressed patients (Table 2). At this time the correlation between affect intensity and NPT measures can be detected even after controlling for the effect of affect intensity on phasic REM sleep, While the physiological mechanisms for the relation between phasic and tonic REM sleep and sleep-related penile tumescence have not been clearly delineated, the significant correlation between affect intensity and NPT at posttreatment, even after the effect of affect intensity on REM activity is controlled for, suggests that the relation between daytime affect and NPT is not entirely mediated by alterations in phasic REM sleep.
147 How can we explain the observed relation between affect intensity and NPT? Previous research on “affect intensity” comes from studies of personality. Affect intensity is thought to reflect how individuals vary in their degree of emotional responsiveness (Larsen and Diener, 1987). Affect intensity is seen as a personality trait such that individuals with high affect intensity experience both positive and negative affects to greater degrees than do individuals with lower affect intensity. Research on arousal suggests that individuals with intense affects have relatively enhanced arousal responses to stimuli (Eysenck, 1967; Larsen and Zarate, 1991). Research on the neuropharmacology of sexual behavior suggests that dopaminergic and adrenergic neurotransmitter systems are involved in penile erection (for review, see Segraves, 1989). Augmentation of sexual behavior by central dopamine facilitation and by lowering of central serotonergic activity has also been reported. Perhaps NPT measures and affect intensity are related through common neurotransmitter systems that mediate arousal responsivity. While NPT variables measuring the duration of tumescence correlated with affect variables, the NPT variable “maximum buckling force” also correlated significantly and positively with affect intensity at both pretreatment and posttreatment for depressed patients. These correlations remained significant even after the effect of affect intensity on REM activity reported elsewhere (Nofzinger et al., in pressb) had been controlled for. This suggests that the relation between affect intensity and erectile function is not entirely dependent on measures of tumescence time which are related to the duration of REM sleep. This observation may help to explain some of the instability of “maximum buckling force” in NPT studies (Nofzinger et al., 1993~). While it is possible that the significance of some of the correlations reported represents type-1 error, similar effects were detected at two separate time points for the depressed subjects, suggesting a relation that is stable over time. In the current study, we have suggested a relation between NPT and affect intensity in depressed men. It remains to be seen whether this relation is specific to the state of depression, or whether other groups exhibit similar relations between emotions or affects during the day and tumescence during sleep. We did not observe the same relation in healthy control subjects. It is certainly possible, and likely, that other psychiatric groups may exhibit similar effects of daytime affect intensity on NPT. Schizophrenic patients, for example, have well-documented abnormalities in EEG sleep (Keshavan et al., 1990; Benca et al., 1992; Tandon et al., 1992; Nofzinger et al., 1993~). If the salient variable is low affect intensity (flattening of affect), then schizophrenic patients exhibiting predominantly negative symptoms of schizophrenia may be at in.creased risk for reductions in NPT. In summary, the results of the current study suggest that NPT studies in depressed patients correlate modestly with their daytime emotional experience. Specifically, in depressed men, some of the between-subject variability in NPT is related to the level of emotional responsiveness, or affect intensity, irrespective of daytime sexual function. It remains a matter for further study as to whether this relation is specific to depressed men or whether it may also be present in other patient groups.
148 Acknowledgments. The research reported herein was supported in part by grants MH16804, MH-40023, MH-30915, and MH-00295 from the National Institute of Mental Health. The authors wish to acknowledge the constructive comments of the anonymous reviewers of Psychiatry Research.
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