Inventory identification of cyclothymia. IX. Validation in offspring of bipolar I patients.

We present the ninth in a series of validation studies that support the effectiveness of the General Behavior Inventory (GBI) in identifying cyclothymia. This study assessed the potential utility of the GBI in family and offspring studies by evaluating its ability to satisfy three prerequisites for use in such research: (1) identification of cyclothymia familially related to bipolar I disorder, (2) use with young adolescents, and (3) "insensitivity" to the effects of nonaffective psychopathology and parental nonaffective disorder in the offspring of control probands. The GBI and a blind, structured diagnostic interview were administered to 37 offspring of bipolar I patients and 21 offspring of psychiatric control patients, Twenty-seven percent of the offspring of bipolar patients, but none of the control offspring, were found to have bipolar forms of affective disorder, primarily cyclothymia (24%). Concordance between the GBI and interview-derived diagnoses was 95% to 97%, with 98% specificity and 80% to 90% sensitivity, depending on cutting score location. Together with the results of previous studies, the findings suggest that the GBI holds promise for the identification of cyclothymia in several research and clinical contexts.

Seasonal independence of low prolactin concentration and high spontaneous eye blink rates in unipolar and bipolar II seasonal affective disorder.

Twenty-four subjects with seasonal affective disorder (SAD: bipolar II, n = 14; unipolar, n = 10) and 20 normal controls were assessed for early follicular basal serum prolactin (PRL) concentration in winter and summer. Luteal basal PRL concentration was assessed in winter. The PRL values represented the mean of three values derived during a 45-minute period. A subset of 17 subjects with SAD and 11 controls were also assessed for spontaneous eye blinking via a polygraphic recording in winter and summer. In winter, compared with controls, subjects with SAD were characterized by significantly lower follicular (10.1 vs 4.5 micrograms/L, respectively) and luteal (14.4 vs 7.4 micrograms/L, respectively) PRL values and by significantly higher eye blink rates (30 vs 61 blinks per 3 minutes, respectively). In summer, controls and subjects with SAD showed similar significant differences in follicular PRL values (9.3 vs 3.9 micrograms/L, respectively) and eye blink rates (25 vs 67 blinks per 3 minutes, respectively). No significant differences in PRL values or eye blink rates were found between the bipolar II and unipolar forms of SAD in either season. Results were discussed in terms of dopamine functioning.

Regional electroencephalographic asymmetries in bipolar seasonal affective disorder before and after exposure to bright light.

Electroencephalographic (EEG) asymmetries found in nonseasonal depression were examined in seasonal affective disorder before and after bright-light exposure. Subjects with seasonal depression demonstrated the expected pattern of frontal asymmetry both when depressed and following light-induced remission. Right-hemisphere EEG coherence, by contrast, served as a state-dependent indicator of seasonal depression.

Effect of phototherapy on spontaneous eye blink rate in subjects with seasonal affective disorder.

Eye blink rate was measured in four subjects with seasonal affective disorder and in four control subjects before and after phototherapy. The subjects with seasonal disorder blinked twice as often as the control subjects before therapy but no differently after phototherapy.

The behavioral high-risk paradigm and bipolar affective disorder, VIII: Serum free cortisol in nonpatient cyclothymic subjects selected by the General Behavior Inventory.

The degree of biologic concordance between bipolar affective disorder and cyclothymia was assessed within a 3-hour protocol of cortisol functioning. Cyclothymic subjects, selected by the General Behavior Inventory, showed cortisol hypersecretion approaching that of subjects with major affective disorders; they also showed poor modulation of cortisol levels over time, the degree of which was related to increased current level of depression and to a chronic, intermittent depressive course. These results not only support the validity of the General Behavior Inventory but also suggest that cyclothymic subjects with a chronic depressive course may experience persistent biologic disturbance similar to that found during episodes of major depression.

Seasonal and mood independence of low basal prolactin secretion in premenopausal women with seasonal affective disorder.

To test hypotheses of opposing roles of dopamine and serotonin in prolactin secretion in seasonal affective disorder, the authors determined basal serum prolactin concentrations for premenopausal women, eight with and 14 without seasonal affective disorder, in late afternoon during the follicular phase of the menstrual cycle (and a subgroup during the luteal phase) in winter and summer. Despite their significantly higher Hamilton depression scale scores in winter than in summer, the patients had significantly lower prolactin concentrations than the control subjects in both seasons. These results suggest that low prolactin secretion may be a trait characteristic in seasonal affective disorder.

Affective symptoms, schizophrenia, and the conceptual ambiguity of postpsychotic depression.

McGlashan and Carpenter (1979) have critiqued our article (Goplerud and Depue 1978), in which we suggested that postpsychotic depression and bipolar depressive disorder may well be related. Their critique has many problems and, most importantly, raises new ambiguities concerning the definition of postpsychotic depression. Therefore, we have attempted to clarify the issues their discussion raises.

The diagnostic ambiguity of postpsychotic depression.

A clearly differentiated episode of depression in the aftermath of acute psychosis reportedly occurs in approximately 25 percent of all patients hospitalized with a diagnosis of acute schizophrenia. A comparison of premorbid functioning, symptomatology, and clinical course in patients with a postpsychotic depression following acute schizophrenic episodes and patients in the depressed phase of bipolar depressive illness suggests a high congruence between the two disorders. The results support the growing evidence that bipolar depressive illness is frequently misdiagnosed as acute schizophrenia.

General behavior inventory identification of unipolar and bipolar affective conditions in a nonclinical university population.

Validated the General Behavior Inventory (GBI), revised to identify unipolar as well as bipolar affective conditions, in a nonclinical sample (n = 201) against naive, interview-derived diagnoses. For bipolar and unipolar conditions, respectively, the GBI had high positive (.94, .87) and negative (.99, .93) predictive power with the effect of prevalence considered, adequate sensitivity (.78, .76), high specificity (.99, .99), and adequate selection ratios for sampling of affective and nonaffective subjects from nonclinical populations for research purposes. The utility of the GBI in several different research contexts is discussed.

Differential association of traits of fear and anxiety with norepinephrine- and dark-induced pupil reactivity.

The relation between fear and anxiety remains unclear, though psychometric data strongly suggest they are independent emotional systems. Because central norepinephrine (NE) projection systems are at the core of models of both fear and anxiety, the present experiment explored whether this independence extends to NE functioning. Two different aspects of NE functioning were assessed in a healthy young adult sample (N = 18): pupillary reactivity to (a) a specific NE alpha-1 agonist challenge to assess receptor reactivity and (b) a darkness challenge to assess contributions of central NE. Pupillary reactivity to the former was strongly and specifically related to A. Tellegen's (1982) Multidimensional Personality Questionnaire (MPQ) Harm Avoidance scale (i.e., trait fear), whereas the latter was strongly and specifically related to MPQ Negative Emotionality (i.e., trait anxiety). Implications for conceptualizing fear and anxiety as emotional systems are discussed.

Dopamine and the structure of personality: relation of agonist-induced dopamine activity to positive emotionality.

Modern trait theories of personality include a dimension reflecting positive emotionality (PE) based on sensitivity to signals of incentive-reward. In animals, responsivity within an emotional system analog of PE is dependent on brain dopamine (DA) activity. To determine whether human PE trait levels are also associated with central DA, effects of a specific DA D2 receptor agonist were assessed in Ss who were widely distributed along the trait dimension of PE. The degree of agonist-induced reactivity in two distinct central DA indices was strongly and specifically associated with trait levels of PE, but not with other personality traits. The results suggest that the trait structure of personality may be related to individual differences in brain DA functioning.

Dimensional measurement of seasonal variation in mood and behavior.

Recent epidemiologic studies have found that the behaviors that characterize seasonal affective disorder (SAD) show seasonal variation in 92%-95% of the general population, suggesting that seasonal variation in behavior and mood is a continuous, dimensional variable extending throughout the general population, defined at the upper extreme by SAD. Research into population seasonality will require a dimensional measure of seasonal variation in mood and behavior that produces a broad, finely graded distribution of seasonality scores sensitive to individual differences throughout the entire range of scores. Accordingly, the Inventory of Seasonal Variation (ISV) was developed as such a measure. This study demonstrated that the ISV has high internal structural validity and is highly sensitive to individual differences in seasonality across its entire range of scores in the normal population. This latter characteristic is not shared by other existing measures of seasonality. Initial external validity of the ISV was supported in that the mean of ISV scores of a SAD sample was found to lie at the 97th percentile of the normal population of scores. Analysis of ISV scores revealed that a winter pattern of seasonality was reported by over 95% of subjects, a pattern that was more pronounced in women than men, while a summer type of seasonality was reported by only 0.6% of the general population.

Behavioral engagement level, variability, and diurnal rhythm as a function of bright light in bipolar II seasonal affective disorder: an exploratory study.

Six patients with bipolar II seasonal affective disorder (SAD) and seven normal control subjects rated their moods in winter at six fixed times each week-day during 1 week of dim and 2 weeks of bright light. The scales rated represent the mood dimension specifically associated with depression, a dimension here called behavioral engagement (BE). Compared with controls, depressed SAD subjects (1) showed lower BE levels across all rating times of the day, (2) were more likely to show diurnal variation in BE, (3) displayed more between-day instability in BE diurnal rhythm, and (4) exhibited greater short-term lability (change within 3 hours) in BE. Bright light reduced or eliminated all group differences in BE level and variability.

Thermoregulatory response to thermal challenge in seasonal affective disorder: a preliminary report.

It has recently been proposed that alterations in central dopamine (DA) functional activity may, in part, account for certain behavioral changes observed in seasonal affective disorder (SAD) during the winter. To explore this possibility, a preliminary study of thermoregulatory heat loss to an endogenous heat challenge--a strongly DA-dependent process--was undertaken in groups of four SAD woman and four nonpsychiatric control women across three conditions (winter, after successful phototherapy, and summer). Homeostatic heat loss during recovery from heat challenge in SAD, but not in control, subjects was found to be a significant function of light condition and of clinical state. Thermoregulatory heat loss in SAD subjects was significantly blunted in winter during depression, was similar in efficiency to control subjects after a successful antidepressant response to phototherapy, and tended to be more efficient than controls in summer during a euthymic state. Results raise the possibility that a common effect of phototherapy and summer light conditions is a facilitation of central DA activity in SAD.

Heat-loss response to a thermal challenge in seasonal affective disorder.

This study extends earlier findings of poorly facilitated postexercise heat loss during the winter in seasonal affective disorder (SAD). While depressed in the winter, 19 SAD subjects exhibited a significantly impaired postexercise heat loss relative to 10 control subjects. During the summer while euthymic, SAD subjects did not significantly differ from control subjects in postexercise heat loss. Since thermoregulatory heat loss is a highly dopamine-dependent process, these results support earlier findings of poorly facilitated dopamine availability in SAD during the winter and suggest a centrally mediated effect of light in SAD.