Dimensional endophenotypes in bipolar disorder: Affective dysregulation and psychosis proneness

Background

The clinical phenotype of bipolar disorder (BPD) is heterogeneous and the genetic architecture of the disorder is complex and not well understood. Given these complications, it is possible that the identification of intermediate phenotypes (“endophenotypes”) will be useful in elucidating the complex genetic mechanisms that result in the disorder. The examination of unaffected relatives is critical in determining whether a particular trait is genetically-relevant to BPD. However, few dimensional traits related to BPD have been assessed in unaffected relatives of patients.

Methods

We assessed affective temperament and schizotypy in 55 discordant sibling pairs and 113 healthy controls (HCs) using the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego, Auto-questionnaire version (TEMPS-A) to assess affective temperament and the Schizotypal Personality Questionnaire (SPQ) to assess schizotypy.

Results

BPD patients scored significantly higher than HCs on all subscales of the SPQ and on all but one subscale (hyperthymic) of the TEMPS-A (all p<0.01). Siblings demonstrated scores that were significantly intermediate to patients and HCs on the anxious subscale of the TEMPS-A and on the interpersonal deficits and disorganized subscales of the SPQ.

Limitations

We did not investigate the BPD spectrum as most patients were diagnosed with BPD I (n=47). Most of the patients had experienced psychosis (n=42) and so we were unable to examine whether psychosis status impacted upon affective temperament or schizotypy in patients or their siblings.

Conclusion

These data suggest that schizotypy and affective temperament represent dimensional traits that are likely to underlie the genetic risk for BPD.     

Affective temperaments as measured by TEMPS-A in patients with bipolar I disorder and their first-degree relatives: a controlled study

BACKGROUND: The aims of this study were to identify the dominant affective temperamental characteristics of patients with bipolar disorder (BP) and their clinically well first-degree relatives and to compare the prevalence rates of these temperaments with those in healthy control subjects. METHODS: One hundred bipolar I probands and their 219 unaffected first-degree relatives were enrolled in the study. The control group consisted of healthy subjects without any personal or family history of bipolar disorder, matched with the age and gender of the probands and first-degree relatives. To identify the dominant affective temperaments, the Turkish version of TEMPS-A scale was used. RESULTS: At least one dominant temperament was found in 26% of the proband group, in 21.9% of the relative group, and 6.0% and 10.0% of the control groups, respectively. The most noteworthy finding was that both the probands and their relatives had significantly higher frequency of hyperthymic temperament than the controls. LIMITATIONS: Temperament had not been assessed premorbidly in the probands with bipolar disorder. CONCLUSIONS: The study supports the familial, possibly genetic, basis for the hyperthymic temperament in the genesis of bipolar I dosorder. That the cyclothymic temperament was not similarly represented, may be due to the higher specificity of the cyclothymic temperament to the bipolar II sybtype (which we did not study). More research is needed on the relevance of cyclothymic and other temperaments to the genetics of bipolar disorders selected by rigorous subtyping along the clinical spectrum of bipolarity.     

Familiality of temperament in bipolar disorder: support for a genetic spectrum

BACKGROUND: The array of different diagnoses and clinical presentations seen in the family members of bipolar probands suggests a quantitative or spectrum phenotype. Consistent with this idea, it has been proposed that an underlying quantitative variation in temperament may be the primary phenotype that is genetically transmitted and that it in turn predisposes to bipolar disorder (BP). Choosing the appropriate phenotypic model for BP is crucial for success in genetic mapping studies. To test this theory, various measures of temperament were examined in the family members of bipolar probands. We predicted that a gradient of scores would be observed from those with BP to those with major depression to unaffected relatives to controls. METHODS: Members of 85 bipolar families and 63 control subjects were administered clinical interviews for diagnosis (SCID) and two temperament assessments, the TEMPS-A and TCI-125. Subjects with BP, major depressive disorder, unaffected relatives, and controls were compared on each temperament scale and on eight factors extracted from a joint factor analysis of the TEMPS-A and TCI-125. RESULTS: The four groups were found to be significantly different and with the expected order of average group scores for four of the TEMPS-A scales, three of the TCI-125 scales, and one of the extracted factors. On the fifth TEMPS-A scale, hyperthymic, controls scored higher than the other three subject groups contrary to expectations. Significant differences were seen between unaffected relatives and controls on the hyperthymic scale and on the first extracted factor, anxious/reactive. LIMITATIONS: Controls were mainly recruited through advertisements, which may have introduced an ascertainment bias. It is also possible that mood state at the time of completing the questionnaire influenced subject's rating of their temperament. Additionally, bipolar I and bipolar II subjects were placed in the same group even though they had some differing clinical features. CONCLUSIONS: Our data support the theory that some dimensions of temperament are transmitted in families as quantitative traits that are part of a broader bipolar spectrum. In particular, the hyperthymic scale of the TEMPS-A and the anxious/reactive extracted factor distinguished unaffected relatives from controls. The hyperthymic scale yielded results opposite to expectation with controls higher than any family group. This may be an artifact of the self-rated form of the questionnaire, a consequence of our grouping bipolar I and II subjects together, or the result of a "protective" factor and bears further study. Nevertheless, both of these scales may be useful quantitative traits for genetic mapping studies.     

Temperament and personality in bipolar II disorder

BackgroundThere is limited research examining temperament and personality in bipolar II disorder. We sought to determine any over-represented temperament and personality features in bipolar II disorder compared to other affective groups.MethodScores on a self-report measure of temperament and personality were examined in a sample of 443 participants diagnosed with unipolar, bipolar I and bipolar II disorder.ResultsAfter controlling for age, gender, age of depression onset and current depression severity, those with bipolar II disorder were characterized by higher irritability, anxious worrying, self-criticism and interpersonal sensitivity scores, and with lower social avoidance scores compared to unipolar participants. No differences were found between bipolar sub-types on any temperament and personality sub-scales.Limitations included the lack of a control group, a relatively small sample of bipolar I participants, and with the cross-sectional design disallowing conclusions regarding premorbid personality traits as opposed to illness 'scarring' effects.ConclusionsFurther research should seek to clarify whether certain temperament and personality styles are over-represented in bipolar II disorder. Any over-represented characteristics may assist with diagnostic differentiation from phenomenologically similar conditions and lead to more appropriate clinical management.     

Cognitive functioning in patients with familial bipolar I disorder and their unaffected relatives

BACKGROUND: Impairments in verbal learning and memory, executive functions and attention are manifest in some euthymic patients with bipolar disorder (BPD). However, evidence is sparse on their putative role as aetiologically important genetic vulnerability markers for the disorder. This population-based study examined the cognitive functions of affected and unaffected individuals in families with BPD. The aim was to discover whether any cognitive function would indicate genetic liability to the disorder and could thus be regarded as endophenotypes of BPD. METHOD: A diagnostic interview and a neuropsychological test battery were administered to 32 familial bipolar I disorder patients, 40 of their unaffected first-degree relatives and 55 controls, all representing population-based samples. RESULTS: Unaffected first-degree relatives showed impairment in psychomotor performance speed and slight impairment in executive function. Bipolar patients were impaired in verbal learning and memory compared with unaffected relatives and controls. They also differed from controls in tasks of executive functions. There were no difference between the groups in simple attention and working memory tasks. CONCLUSIONS: Impaired psychomotor performance speed and executive function may represent endophenotypes of BPD, reflecting possible underlying vulnerability to the disorder. Verbal memory impairments appear to be more related to the fully developed disorder.     

Depressive personality in the relatives of outpatients with dysthymic disorder and episodic major depressive disorder and normal controls.

BACKGROUND: This study examined whether there is a familial relationship between depressive personality and the mood disorders. METHOD: Rates of depressive personality were compared in 161 relatives of outpatients with dysthymic disorder (DD), 75 relatives of outpatients with non-chronic major depressive disorder (MDD), and 90 relatives of normal controls. All probands and relatives were evaluated using structured diagnostic interviews for Axis I disorders and depressive personality traits. RESULTS: The relatives of patients with DD exhibited a significantly higher rate of depressive personality than the relatives of normal controls, while the relatives of patients with MDD fell in between, and did not differ from, the other two groups. These results held after controlling for a lifetime history of mood disorder in the relatives, and could not be explained by an increased rate of depressive personality in the DD probands. LIMITATIONS: The sample size was modest, comorbid non-mood Axis I and II disorders in the relatives were not controlled, and DSM-IV criteria for depressive personality disorder were not yet available at the time the study was undertaken. CONCLUSION: These findings are consistent with the view that depressive personality is part of a spectrum of mood disorders with a shared familial liability, but suggest that this link is strongest with chronic forms of depression such as DD and double depression.     

缓解期重性抑郁与心境恶劣患者人格特征及人格障碍研究

目的：研究重性抑郁症(MDD)和心境恶劣障碍(DD)患者在人格维度、人格特质水平及人格模型及人格障碍倾向性方面的特征。方法：采用NEO-PI-R个性调查表及人格诊断问卷(PDQ^ 4)对58例MDD和57例DD患者及115例正常人进行测试。结果：MDD和DD在NEO-PI-R的五因素人格模型的外向性、严谨性得分均低于正常组，DD患者的神经质分高于MDD患者，MDD患者的顺同性分高于正常组；在30个特质层面上，MDD和DD与正常组之间有显著性差异，DD患者的N1(焦虑)、N4(自我意识)分明显高于MDD患者，E4(热情性)、A1(信任感)分明显低于MDD患者；MDD和DD在PDQ^ 4的边缘型(BDL)、回避型(AVD)、抑郁型(DEP)、分裂性(SZD)、偏执型(PND)、强迫型(OBC)人格障碍得分明显高于正常组，DD患者在分裂型得分明显高于MDD患者，在表演型(HST)分明显高于正常组。结论：MDD和DD的人格特征既有共同的之处，也存在差异。两者均伴有人格障碍，但DD患者比MDD患者人格障碍更明显。     

Lack of association between polymorphisms of the dopamine receptor D4 and dopamine transporter genes and personality traits in a Korean population

Human personality traits have a considerable genetic component. Cloninger et al. were the first to postulate that certain personality traits, such as novelty seeking, are related to the dopamine neurotransmitter system. In this study, we investigated the associations between dopamine receptor D4 (DRD4) exon III and dopamine transporter (DAT1) polymorphisms and personality traits. The DRD4 and DAT1 gene polymorphisms were genotyped in 214 healthy Korean subjects, whose personality traits were assessed with the Temperament and Character Inventory (TCI). There were no significant differences between scores of TCI temperament dimensions (novelty seeking, harm avoidance, reward dependence, and persistence) and DRD4 gene polymorphism. The DAT1 gene polymorphisms also showed no significant association with any of the temperament subscales of the TCI. These data suggest that DRD4 and DAT1 gene polymorphism may not associated with personality traits in a Korean population.     

A comparison of recovered bipolar patients, healthy relatives of bipolar probands, and normal controls using the short TEMPS-A

OBJECTIVE: To investigate the presence of temperament dysregulation in healthy relatives of bipolar probands (RBP), a population at high risk for developing mood disorders, by comparing them with clinically recovered bipolar patients (BP) and normal controls (NC). METHOD: 52 RBP and 23 BP were originally recruited for a multicenter genetic study in bipolar disorders. NC (n=102) were also recruited by newspaper advertisement, radio and television announcements, flyers, newsletters, or word of mouth. All volunteers were asked to complete the TEMPS-A Scale, a self-report questionnaire designed to measure temperamental variations in psychiatric patients and healthy volunteers. In scoring temperaments, we relied upon the short validated version of the TEMPS-A [J. Affect. Disord. (2004)], from which traits with loadings <0.035 had been deleted. Results: To examine differences in temperament dimensions among the three groups, a MANCOVA model was constructed using diagnostic group as the fixed factor (BP vs. RBP vs. NC); effects of age and gender were adjusted as covariates. MANCOVA showed overall group effect on the dependent variables (Hotelling's F5,175=6.64, p<0.001). Four dependent variables (dysthymic, cyclothymic, irritable, and anxious temperaments) showed significant between-group differences. RBP showed lower cyclothymic temperament scores than BP, but higher scores than NC. BP and RBP showed higher anxious temperament scores than NC. Hyperthymic scores were significantly highest in the NC. LIMITATION: In view of the small cell sizes, bipolar I vs. bipolar II subanalyses could not be conducted. CONCLUSIONs: Methodologic strengths of the present analyses is that the BP group had clinically recovered, and we used the validated short version of the TEMPS-A for the present analyses. Our findings suggest that some clinically healthy relatives of bipolar probands exhibit a subclinical cyclothymic instability in mood, interest, self-confidence, sleep, and/or energy as well as anxiety proneness that is not observed among normal controls. These traits may represent vulnerability markers and could presumably be used to identify individuals at high risk for developing bipolar spectrum disorders, or specific clinical subtypes (e.g., bipolar I, bipolar II) within this spectrum. This is a conceptual perspective with many unanswered questions. Resolution of these questions will require innovative definitions of phenotypes to be included in the analyses of the temperament subscales in different populations. The temperament subscales themselves need to be calibrated properly, to find out which traits or specific combinations of trains are most promising. More extensive and complex quantitative trait analyses of these temperaments in a much expanded sample are reported elsewhere in this issue [J. Affect. Disord. (2004)].     

TEMPS-a scale in 'mixed' and 'pure' manic episodes: new data and methodological considerations on the relevance of joint anxious-depressive temperament traits

BACKGROUND: Temperament is an important factor in affective illness. There is some indication that mixed episodes result from an admixture of inverse temperamental factors (e.g. depressive and/or anxious) to a manic syndrome. To test this hypothesis, which has been first formulated by Akiskal [Clin. Neuropharmacol. 15 (Suppl. 1A) (1992) 632-633], we compared the temperament of non-acute bipolar affective patients with and without the history of a previous mixed episode. METHODS: Patients who had been hospitalized for a bipolar disorder were re-assessed at least 6 months after their last in-patient treatment. Those who met the criteria for a partially remitted or full affective or psychotic episode at re-assessment were excluded from the study. Data concerning illness history, current psychopathology (SCID-I interview), depression (BDI), mania (Self-Report Manic Inventory) and temperament (TEMPS-A scale) were obtained. Patients with and without a history of previous mixed episodes were compared. RESULTS: Of 49 eligible former patients, 22 subjects with and 23 subjects without a former mixed episode in bipolar affective disorder fulfilled the inclusion criteria. Subjects suffering from bipolar affective disorder exhibited significantly more depressive and anxious and less hyperthymic temperament, if they had experienced a mixed episode previously. Concerning cyclothymic and irritable temperament, bipolar affective patients with a former mixed episode presented non-significantly higher scores. Patients with a former mixed episode presented with higher depression scores than patients without such a history. No group differences were found concerning current mania scores. LIMITATIONS: (1). This is a preliminary report from an ongoing study. (2). Temperament had not been assessed premorbidly. (3). Although group comparisons revealed significant differences, these did not seem great enough to fully explain the emergence of a mixed episode. CONCLUSION: Our findings support the study's hypothesis that mixed episodes occur more often in subjects with an inverse temperament (e.g. depressive and anxious), although it cannot be ruled out that subsyndromal features of the bipolar illness had an effect on temperament assessment.     

Temperament and personality in bipolar I patients with and without mixed episodes

BACKGROUND: Personality and temperament are supposed to have an impact on the clinical expression and course of an affective disorder. There is some indication, that mixed episodes result from an admixture of inverse temperamental factors to a manic syndrome. In a preliminary report [Brieger, P., Roettig, S., Ehrt, U., Wenzel, A., Bloink, R., Marneros, A., 2003. TEMPS-a scale in 'mixed' and 'pure' manic episodes: new data and methodological considerations on the relevance of joint anxious-depressive temperament traits. J. Affect. Disord. 73, 99-104] we reported support for this assumption. The present study completes the preliminary results and compares patients with and without mixed episodes with respect to personality and personality disorders in addition. METHODS: Patients who had been hospitalized for bipolar I disorder were reassessed after 4.8 years. We examined temperament (TEMPS-A), personality (NEO-FFI) and frequency of personality disorders (SCID-II). Furthermore, illness-related parameters like age at first treatment, depressive and manic symptomatology, frequency and type of episodes and level of functioning were obtained and patients with and without mixed episodes were compared. RESULTS: Patients with (n=49) and without mixed episodes (n=86) did not differ significantly with regard to the illness-related parameters and personality dimensions. The frequency of personality disorders was significantly higher in patients with prior mixed episodes. With respect to temperament, scores of the depressive, cyclothymic, irritable and anxious temperament were significantly higher in patients with mixed episodes. LIMITATIONS: We were not able to assess premorbid temperament and premorbid personality. CONCLUSIONS: The findings of the present study support the assumption of Akiskal [Akiskal, H.S., 1992b. The distinctive mixed states of bipolar I, II, and III. Clin. Neuropharmacol. 15 Suppl 1 Pt A, 632-633.] that mixed episodes are more frequent in subjects with inverse temperament.     

A dopamine transporter polymorphism is a risk factor for borderline personality disorder in depressed patients

BACKGROUND: Borderline personality disorder (BPD) is often co-morbid with major depression and may complicate its treatment. We were interested in differences in genetic and developmental risk factors between depressed patients with or without a co-morbid BPD. METHOD: Out-patients with major depressive disorder were recruited for two treatment trials. Assessment of depressed patients included the assessment of personality disorders, developmental risk factors and DNA samples for genetic analyses. RESULTS: In each study there was a significant association between the 9-repeat allele of the dopamine transporter (DAT1) and BPD, with odds ratios (OR) > 3 and p < or = 0.02. This association remained significant when developmental risk factors for BPD (childhood abuse and neglect and borderline temperament) were also included in the analyses. The OR was even larger in the depressed patients aged > or = 35 years (OR 9.31, p = 0.005). CONCLUSION: This replicated association in depressed patients between the 9-repeat allele of DAT1 and BPD may provide clues to understanding the neurobiology of BPD. The finding that the association is larger in the older depressed patients, suggests that the 9-repeat allele may be associated with a poorer prognosis BPD, rather than a young adult limited variant of BPD.     

Can personality traits predict increases in manic and depressive symptoms?

BACKGROUND: There has been limited research investigating personality traits as predictors of manic and depressive symptoms in bipolar individuals. The present study investigated the relation between personality traits and the course of bipolar disorder. The purpose of this study was to identify specific personality traits that predict the course of manic and depressive symptoms experienced by bipolar individuals. METHODS: The sample consisted of 39 participants with bipolar I disorder assessed by the Structured Clinical Interview for DSM-IV. Personality was assessed using the NEO Five-Factor Inventory. The Modified Hamilton Rating Scale for Depression and the Bech-Rafaelsen Mania Rating Scale were used to assess symptom severity on a monthly basis. RESULTS: Consistent with previous research on unipolar depression, high Neuroticism predicted increases in depressive symptoms across time while controlling for baseline symptoms. Additionally, high Conscientiousness, particularly the Achievement Striving facet, predicted increases in manic symptoms across time. LIMITATIONS: The current study was limited by the small number of participants, the reliance on a shortened version of a self-report personality measure, and the potential state-dependency of the personality measures. CONCLUSIONS: Specific personality traits may assist in predicting bipolar symptoms across time. Further studies are needed to tease apart the state-dependency of personality.     

Temperamental commonalities and differences in euthymic mood disorder patients, creative controls, and healthy controls

OBJECTIVE: Understanding of mood disorders can be enhanced through assessment of temperamental traits. We explored temperamental commonalities and differences among euthymic bipolar (BP) and unipolar (MDD) mood disorder patients, creative discipline graduate student controls (CC), and healthy controls (HC). METHODS: Forty-nine BP, 25 MDD, 32 CC, and 47 HC completed self-report temperament/personality measures including: The Affective Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-A); the Revised NEO Personality Inventory (NEO-PI-R); and the Temperament and Character Inventory (TCI). RESULTS: Euthymic BP, MDD, and CC, compared to HC, had significantly increased cyclothymia, dysthymia and irritability scores on TEMPS-A; increased neuroticism and decreased conscientiousness on NEO-PI-R; and increased harm avoidance and novelty seeking as well as decreased self-directedness on TCI. TEMPS-A cyclothymia scores were significantly higher in BP than in MDD. NEO-PI-R openness was increased in BP and CC, compared to HC, and in CC compared to MDD. TCI self-transcendence scores in BP were significantly higher than in MDD, CC, and HC. LIMITATIONS: Most of the subjects were not professional artists, and represented many fields; temperament might be different in different art fields. CONCLUSIONS: Euthymic BP, MDD, and CC compared to HC, had prominent temperamental commonalities. However, BP and CC had the additional commonality of increased openness compared to HC. BP had particularly high Cyclothymia scores that were significantly higher then those of MDD. The prominent BP-CC overlap suggests underlying neurobiological commonalities between people with mood disorders and individuals involved in creative disciplines, consistent with the notion of a temperamental contribution to enhanced creativity in individuals with bipolar disorders.     

The distinct temperament profiles of bipolar I, bipolar II and unipolar patients

BACKGROUND: Despite a plethora of studies, controversies abound on whether the long-term traits of unipolar and bipolar patients could be differentiated by temperament and whether these traits, in turn, could be distinguished from subthreshold affective symptomatology. METHODS: 98 bipolar I (BP-I), 64 bipolar II (BP-II), and 251 unipolar major depressive disorder (UP-MDD) patients all when recovered from discrete affective episodes) and 617 relatives, spouses or acquaintances without lifetime RDC diagnoses (the comparison group, CG) were administered a battery of 17 self-rated personality scales chosen for theoretical relevance to mood disorders. Subsamples of each of the four groups also received the General Behavior Inventory (GBI). RESULTS: Of the 436 personality items, 103 that significantly distinguished the three patient groups were subjected to principal components analysis, yielding four factors which reflect the temperamental dimensions of "Mood Lability", "Energy-Assertiveness," "Sensitivity-Brooding," and "Social Anxiety." Most BP-I described themselves as near normal in emotional stability and extroversion; BP-II emerged as labile in mood, energetic and assertive, yet sensitive and brooding; MDD were socially timid, sensitive and brooding. Gender and age did not have marked influence on these overall profiles. Within the MDD group, those with baseline dysthymia were the most pathological (i.e., high in neuroticism, insecurity and introversion). Selected GBI items measuring hypomania and biphasic mood changes were endorsed significantly more often by BP-II. Finally, it is relevant to highlight a methodologic finding about the precision these derived temperament factors brought to the UP-BP differentiation. Unlike BP-I who were low on neuroticism, both BP-II and UP scored high on this measure: yet, in the case of BP-II high neuroticism was largely due to mood lability, in UP it reflected subdepressive traits. LIMITATION: We used self-rated personality measures, a possible limitation generic to the paper-and-pencil personality literature. It is therefore likely that BP-I may have over-rated their "sanguinity"; or should one consider such self-report as a reliable reflection of one's temperament? One can raise similar unanswerable questions about "depressiveness" and "mood lability." CONCLUSION: As contrasted to CG and published norms, the postmorbid self-described "usual" personality is 1) sanguine among many, but not all, BP-I; 2) labile or cyclothymic among BP-II; and 3) subanxious and subdepressive among UP. It is further noteworthy that with the exception of BP-II, the temperament scores of BP-I and MDD were within one SD from published norms. Rather than being pathological, these attributes are best conceived as subclinical temperamental variants of the normal, thereby supporting the notion of continuity between interepisodic and episodic phases of affective disorders. These findings overall are in line with Kraepelin's views and contrary to the DSM-IV formulation of axis-II constructs as being pathological and sharply demarcated from affective episodes.     

Personality profile of HIV outpatients: preliminary results and remarks on clinical management

BACKGROUND: Currently, HIV is one of the most widely spread epidemics in the world. The specificity of the mode of transmission, the well-known severity of the prognosis, and the kind of therapies used are peculiarities of this illness. Personality traits of individuals with HIV may influence conditions for the infection itself. On the other hand, it is possible that personality traits may influence the course of the illness and the willingness of the patients to adhere to treatment. The present study assessed the personality traits of a heterogeneous group of seropositive subjects compared with healthy controls to determine specific temperament and character traits of this population. METHODS: The Temperament and Character Inventory (TCI) was administered to 126 HIV-positive outpatients belonging to different risk categories for HIV infection and to a sample of healthy individuals matched for sex, age, and socioeconomic parameters. RESULTS: Drug-dependent HIV-positive patients displayed higher scores in novelty seeking and harm avoidance and lower scores in self-directedness compared with healthy controls. Non-drug-dependent HIV-positive subjects scored significantly higher in self-transcendence. CONCLUSIONS: Temperament and character features significantly differentiate the HIV-positive subjects from controls and those belonging to the different risk categories for HIV infection. Drug-dependent subjects with HIV display more impulsiveness, which possibly predates the HIV infection. They are also more fearful and lack self-directedness. Non-drug-dependent subjects express higher self-transcendence resources, possibly to overcome their difficulties. Both the temperament and character features may influence compliance with treatment and require specific interventions considering these subgroups.     

Heritability and linkage analysis of personality in bipolar disorder

Background

The many attempts that have been made to identify genes for bipolar disorder (BD) have met with limited success, which may reflect an inadequacy of diagnosis as an informative and biologically relevant phenotype for genetic studies. Here we have explored aspects of personality as quantitative phenotypes for bipolar disorder through the use of the Temperament and Character Inventory (TCI), which assesses personality in seven dimensions. Four temperament dimensions are assessed: novelty seeking (NS), harm avoidance (HA), reward dependence (RD), and persistence (PS). Three character dimensions are also included: self-directedness (SD), cooperativeness (CO), and self-transcendence (ST).

Methods

We compared personality scores between diagnostic groups and assessed heritability in a sample of 101 families collected for genetic studies of BD. A genome-wide SNP linkage analysis was then performed in the subset of 51 families for which genetic data was available.

Results

Significant group differences were observed between BD subjects, their first-degree relatives, and independent controls for all but RD and PS, and all but HA and RD were found to be significantly heritable in this sample. Linkage analysis of the heritable dimensions produced several suggestive linkage peaks for NS (chromosomes 7q21 and 10p15), PS (chromosomes 6q16, 12p13, and 19p13), and SD (chromosomes 4q35, 8q24, and 18q12).

Limitations

The relatively small size of our linkage sample likely limited our ability to reach genome-wide significance in this study.

Conclusions

While not genome-wide significant, these results suggest that aspects of personality may prove useful in the identification of genes underlying BD susceptibility.     

Different personalities between depression and anxiety

We examined the different personality dimensions between depression and anxiety with Cloninger's seven-factor model of temperament and character. The Temperament and Character Inventory (TCI), which measures four temperament and three character dimensions of Cloninger's personality theory (125-item short version), the Self-rating Depression Scale (SDS), and the State-Trait Anxiety Inventory (STAI) were administered to 223 Japanese students. With hierarchical regression analysis, the SDS score was predicted by scores of Harm-Avoidance, Self-Directedness, and Self-Transcendence, even after controlling for the STAI score. The STAI score was predicted by scores of Self-Directedness and Cooperativeness, even after controlling for the SDS score. More importance should be attached to these dimensions of character because they might contribute to both depression and anxiety. © 1998 John Wiley & Sons, Inc. J Clin Psychol 54: 1043–1051, 1998.     

Temperament-creativity relationships in mood disorder patients, healthy controls and highly creative individuals

OBJECTIVE: To investigate temperament-creativity relationships in euthymic bipolar (BP) and unipolar major depressive (MDD) patients, creative discipline controls (CC), and healthy controls (HC). METHODS: 49 BP, 25 MDD, 32 CC, and 47 HC (all euthymic) completed three self-report temperament/personality measures: the Revised NEO Personality Inventory (NEO-PI-R), the Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A), and the Temperament and Character Inventory (TCI); and four creativity measures yielding six parameters: the Barron-Welsh Art Scale (BWAS-Total, BWAS-Like, and BWAS-Dislike), the Adjective Check List Creative Personality Scale (ACL-CPS), and the Torrance Tests of Creative Thinking--Figural (TTCT-F) and Verbal (TTCT-V) versions. Factor analysis was used to consolidate the 16 subscales from the three temperament/personality measures, and the resulting factors were assessed in relationship to the creativity parameters. RESULTS: Five personality/temperament factors emerged. Two of these factors had prominent relationships with creativity measures. A Neuroticism/Cyclothymia/Dysthymia Factor, comprised mostly of NEO-PI-R-Neuroticism and TEMPS-A-Cyclothymia and TEMPS-A-Dysthymia, was related to BWAS-Total scores (r=0.36, p<0.0001) and BWAS-Dislike subscale scores (r=0.39, p<0.0001). An Openness Factor, comprised mostly of NEO-PI-R-Openness, was related to BWAS-Like subscale scores (r=0.28, p=0.0006), and to ACL-CPS scores (r=0.46, p<0.0001). No significant relationship was found between temperament/personality and TTCT-F and TTCT-V scores. CONCLUSIONS: Neuroticism/Cyclothymia/Dysthymia and Openness appear to have differential relationships with creativity. The former could provide affective (Neuroticism, i.e. access to negative affect, and Cyclothymia, i.e. changeability of affect) and the latter cognitive (flexibility) advantages to enhance creativity. Further studies are indicated to clarify mechanisms of creativity and its relationships to affective processes and bipolar disorders.     

Personality and depressive symptoms: a multi-dimensional analysis

BACKGROUND: The relationship of temperamental aspects of personality to symptoms of depression in a community-based sample of 804 individuals was examined using a multi-dimensional approach to account for heterogeneity in symptom patterns. METHOD: The Temperament and Character Inventory (TCI) was used to assess personality and the Center for Epidemiologic Studies Depression scale (CES-D) was used to measure depressive symptoms. Canonical correlation analysis was used to relate CES-D item combinations to temperament traits in multiple dimensions. The relationships between temperament and various conditions correlated with depression were examined using logistic regression. RESULTS: Temperamental aspects of personality are related not only to total CES-D score, but also to the patterns of CES-D items endorsed by subjects. High Harm Avoidance is related to total CES-D score; high Reward Dependence combined with high Persistence is associated with restless sleep and subjective symptoms; high Reward Dependence combined with low Persistence is negatively associated with appetite loss and low energy; high Novelty Seeking is related to maintenance of positive affect and inability to concentrate. High Novelty Seeking is also associated with past suicide attempts, after adjusting for total CES-D score. LIMITATIONS: Cross-sectional data prevent analysis of causation; the severest cases of clinical depression may not be represented in a general population sample. Depressive symptoms are self-reported. CONCLUSION: Substantial differences in level of symptoms and in symptom patterns exist among individuals in a continuum of depressed states and those differences are partially explained by temperament traits.