Dimensions of depression, mania and psychosis in the general population

BACKGROUND: In order to investigate whether correlated but separable symptom dimensions that have been identified in clinical samples also have a distribution in the general population, the underlying structure of symptoms of depression, mania and psychosis was studied in a general population sample of 7072 individuals. METHOD: Data were obtained from the three measurements of the Netherlands Mental Health Survey and Incidence Study (NEMESIS). Symptoms of depression, mania and the positive symptoms of psychosis were assessed using the Composite International Diagnostic Interview. Confirmatory factor-analysis was used to test statistically the fit of hypothesized models of one, two, three or seven dimensions. RESULTS: The seven-dimensional model comprising core depression, sleep problems, suicidal thoughts, mania, paranoid delusions, first-rank delusions and hallucinations fitted the data best, whereas the unidimensional model obtained the poorest fit. This pattern of results could be replicated at both follow-up measurements. The results were similar for the subsamples with and without a lifetime DSM-III-R diagnosis. The seven dimensions were moderately to strongly correlated, with correlations ranging from 0.18 to 0.73 (mean 0.45). CONCLUSIONS: In the general population, seven correlated but separable dimensions of experiences exist that resemble dimensions of psychopathology seen in clinical samples with severe mental illness. The substantial correlations between these dimensions in clinical and non-clinical samples may suggest that there is aetiological overlap between the different dimensions regardless of level of severity and diagnosable disorder.     

A prospective study of the transition rates of subthreshold (hypo)mania and depression in the general population

BACKGROUND: Previous work suggests that subthreshold depression and subthreshold (hypo)mania are common, although little is known about the prognosis in terms of transition to clinical disorder. This paper presents data on the temporal relationship between subthreshold and clinical expression of mood phenotypes. METHOD: In a random general population sample of 7076 individuals, symptoms of depression and (hypo)mania were measured with the Composite International Diagnostic Interview (CIDI) at baseline, after 1 year, and 2 years later. RESULTS: At baseline, the lifetime prevalences of depressive and (hypo)manic symptoms were 17.2% and 1.2% respectively. Predictive values of mood symptoms for a DSM-III-R mood disorder ranged from 14.3% to 50%. (Hypo)manic mood symptoms had much higher predictive values than unipolar manifestations, not only for bipolar disorder but also for major depression. CONCLUSIONS: The subthreshold expressions of depression and (hypo)mania are prevalent and continuous with more severe clinical states. The cross-prediction of mood symptoms may support a continuum from depressive to (hypo)manic symptoms. The high predictive value of (hypo)manic symptoms for mood disorders suggests that the experience of (hypo)manic symptoms is a stronger indicator of vulnerability for mood dysregulation than the experience of depressive symptoms.     

Cannabis use in the community.

BACKGROUND: The illegal use of cannabis has been increasing in many Western countries for the past two decades. Recently, some interest has been shown in modifying legislation and control. The need for general practitioners to be aware of the short- and long-term consequences of cannabis use is increasing, and more information is required about its effects on behaviour, psychological states and the respiratory and cardiovascular systems. The use of general practice populations to study the prevalence of cannabis use and its damaging effects is less represented in the literature than it should be, considering the extent of cannabis consumption. AIM: A study was carried out in 1995 to determine the prevalence of cannabis use in a general practice population and any associated health problems. As a pilot study, samples of cannabis were obtained for forensic analysis. METHOD AND PATIENTS: Two questionnaires were used. One very short enquiry about the use, if any, of the drug, and a longer one about the effects of its use. Data concerning medical effects were included from patients' case notes. Samples of cannabis were obtained for forensic examination. RESULTS: A very high proportion (61%) of patients surveyed indicated some cannabis use (past or present). Thirty-seven per cent had used it in the previous 12 months. Users could be broadly divided into transitory experimenters, regular users and heavy users. Medical problems included those attributed to associated tobacco smoking, other illegal drug use and psychological problems. Benefits perceived by patients recording use were many. Polydrug use and legislation issues were difficult to separate from the effects of cannabis itself. Chest infections, anxiety and depression, and drug dependence were common diagnoses, and 13 of the 32 females in the study group had evidence of cervical smear abnormalities. CONCLUSIONS: Few serious damaging effects from cannabis use itself were identified, although chest infections and anxiety problems were common. Tobacco damage, associated drug use and criminal or legal issues dominated and obscured the important perceived benefits and the scientific understanding of the effects and side effects of the drug. More research into several identified areas is required.     

Cannabis,tobacco smoking,and lung function: a cross-sectional observational study in a general practice population

Background

Health concerns around cannabis use have focused on the potential relationship with psychosis but the effect of cannabis smoking on respiratory health has received less attention.

Aim

To investigate the association between tobacco-only smoking compared with tobacco plus cannabis smoking and adverse outcomes in respiratory health and lung function.

Design and setting

The design was cross-sectional with two groups recruited: cigarette smokers with tobacco pack-years; cannabis smokers with cannabis joint-years. Recruitment occurred in a general practice in Scotland with 12 500 patients.

Method

Exposures measured were tobacco smoking (pack-years) and cannabis smoking (joint-years). Cannabis type (resin, herbal, or both) was recorded by self-report. Respiratory symptoms were recorded using NHANES and MRC questionnaires. Lung function was measured by spirometry (FEV1/FVC ratio).

Results

Participants consisted of 500 individuals (242 males). Mean age of tobacco-only smokers was 45 years; median tobacco exposure was 25 pack-years. Mean age of cannabis and tobacco smokers was 37 years; median tobacco exposure was 19 pack-years, rising to 22.5 when tobacco smoked with cannabis. Although tobacco and cannabis use were associated with increased reporting of respiratory symptoms, this was higher among those who also smoked cannabis. Both tobacco and cannabis users had evidence of impaired lung function but, in fully adjusted analyses, each additional joint-year of cannabis use was associated with a 0.3% (95% confidence interval = 0.0 to 0.5) increase in prevalence of chronic obstructive pulmonary disease.

Conclusion

In adults who predominantly smoked resin cannabis mixed with tobacco, additional adverse effects were observed on respiratory health relating to cannabis use.     

Cannabis use disorders in the USA: prevalence, correlates and co-morbidity

BACKGROUND: The purpose of this study was to present 12-month and lifetime estimates of the prevalence, sociodemographic and clinical correlates, and psychiatric co-morbidity of DSM-IV cannabis abuse and dependence. METHOD: Data were derived from a large nationally representative survey (n=43093) of US adults. RESULTS: The prevalence of 12-month and lifetime DSM-IV cannabis abuse (1.1% and 7.2%) exceeded the corresponding rates of cannabis dependence (0.3% and 1.3%). Being male, Native American, widowed/separated/divorced, and residing in the West increased the odds whereas being Black, Asian or Hispanic decreased the odds of cannabis abuse and dependence. Cannabis dependence was significantly associated with low income. Ages of onset for both cannabis use disorders occurred in adolescence and the majority of individuals with these disorders remained untreated. Co-morbidity was high between cannabis use disorders and other Axis I and II disorders. CONCLUSIONS: Cannabis use disorders continue to present a widespread and serious personal and public health problem. Native Americans were found to have high rates of cannabis use disorders, warranting closer attention to the mental health needs of this subgroup. Associations between cannabis abuse and dependence and Axis I and II disorders were strong, signaling the need for more comprehensive assessment of individuals with cannabis use disorders. Further controlled treatment studies are needed, especially among co-morbid individuals, in view of growing evidence of the adverse personal, medical and societal impacts of cannabis use disorders in the USA.     

Illness fears in the general population

OBJECTIVES: Because relatively little is known about illness fears, we sought to estimate the prevalence, risk factors, and morbidity associated with such fears in the community. METHODS: We conducted a brief telephone survey of persons aged 40 to 65 years from randomly selected households in the Johnson County, Iowa, area. Respondents were asked whether a series of illness and medical care items made them no more nervous, somewhat more nervous, or much more nervous than other people. Those who reported more discomfort were asked to what extent this interfered with medical care or caused impairment or distress. Information about demographic and health characteristics was also obtained. RESULTS: Five hundred persons, 62% of those contacted, responded to the survey. A factor analysis revealed four fear dimensions: illness/injury, medical care, blood/needle, and aging/death. Five percent of respondents reported much more nervousness in relation to at least four of six illness/injury items, 4% indicated that such fears interfered with their medical care, and 5% reported some negative effect on their life. Similarly, 5% of respondents reported much more nervousness in relation to at least two of four medical care items. Illness/injury fears were somewhat more common in persons with lower income and education and in those with medical conditions. CONCLUSIONS: This survey shows that fears of illness and medical care are common in the general population and indicates that lower socioeconomic status and experience with illness are associated with these fears. The findings also suggest that interference with care occurs among those with the strongest fears.     

The use of complementary and alternative medicine in the general population: results from a longitudinal community study

BACKGROUND: Many patients with psychological or physical problems are interested in non-medical approaches. The reasons for the growing popularity of complementary and alternative medicine (CAM) are not well understood considering that evidence of the effectiveness of conventional therapies is greater than ever before. We have examined data from the Zurich Study to determine trends and predictors of CAM use in Switzerland. METHOD: The Zurich Study is a longitudinal community study that was started in 1979 with a sample of 591 participants born in 1958 and 1959. In 1999, the last of six interview waves with face-to-face interviews was conducted. CAM use was analyzed with data from interviews in 1993 and 1999. Polytomous logistic regression analysis focused on the personal, demographic and sociocultural background of CAM users. RESULTS: CAM use in the last 12 months was reported by 21.9% of the participants in 1993 and by 29.5% in 1999. CAM use among those exhibiting either physical or psychological problems was in the ratio of two to one. There was a trend from alternative variants of CAM (homeopathy) to complementary ones (massage, osteopathy, acupuncture). The vast majority of CAM use was in addition to conventional therapies. Predictors of CAM use were, among others, attribution of physical complaints to stress and other psychological variables, very low education level in parents, and lacking political interest. CONCLUSIONS: Besides the sociocultural background, characteristics such as the psychological attribution style play an important role in CAM use. CAM use in Switzerland is mainly of a complementary rather than an alternative nature.     

Personality and the perception of health in the general population

BACKGROUND: Several population-based studies have shown that self-perceived health is a powerful predictor of health outcomes. The extent to which self-perceived health is associated with personality characteristics is, however, largely unknown. We aimed to study the relationship between self-perceived health and personality among adults in the community. METHOD: Data were drawn from the Midlife Development in the United States Survey, a representative sample of adults age 25-74. MANOVA was used to determine the relationship between self-perception of health and personality using the five-factor model. RESULTS: Personality factors were significantly associated with perception of poor health. Among those without self-reported medical problems (N = 834), openness to experience, extraversion and conscientiousness were associated with perception of good health, while neuroticism was associated with the perception of poor health. In subjects with self-reported medical problems (N = 2772), high scores on agreeableness, openness to experience, extraversion and conscientiousness, and low neuroticism scores were associated with perception of good health. These associations remained significant after adjustments for age, gender, race, marital status and education. CONCLUSIONS: Self-perceived health is strongly associated with personality characteristics, both in subjects with and without self-reported medical problems. It is suggested that personality characteristics could contribute to the previously reported associations between self-perceived health and health outcomes.     

Cannabis use and HIV antiretroviral therapy adherence and HIV-related symptoms

Occasional cannabis use has been associated with increased antiretroviral therapy (ART) adherence and relief of HIV symptoms, while heavy use has been associated with low ART adherence and negative psychological symptoms. The purpose of the present study was to investigate differences between non-cannabis use (NC), non-dependent cannabis use (C), and dependent use (CD) in terms of ART adherence and HIV symptoms/ART side effects. A cross-sectional sample of 180 HIV+ individuals (78.3 % male) completed measures of substance use and psychopathology, medication adherence, and HIV symptoms/ART side effects. Adherence was also measured via pill count, viral load, and CD4 count. Results indicated that the CD group reported lower adherence and greater HIV symptoms/ART side effects than the other two groups, with no differences observed between NC and C groups. There is a clinical need to address dependent cannabis use among those prescribed ART. Further examination is needed to ascertain the functions of cannabis use among individuals with HIV.     

Somatoform pain disorder in the general population

BACKGROUND: Chronic pain disorder is assumed to represent a frequent and disabling condition. However, data on the prevalence of somatoform pain symptoms and somatoform pain disorder in the community are limited to date. METHODS: German versions of the Composite International Diagnostic Interview were administered to a representative national sample of 4,075 people. Somatoform pain disorder was diagnosed by standardized diagnostic algorithm based on the DSM-III-R criteria (absence of adequate physical findings). One subgroup was identified as also meeting the DSM-IV criterion B for 'significant distress or psychosocial impairment due to the somatoform pain'. RESULTS: A lifetime prevalence rate of somatoform pain disorder according to DSM-III-R of 33.7% and a 6-month rate of 17.3% was found. When applying the DSM-IV B criterion, the prevalence rate dropped to 12.3 and 5.4%, respectively. In both groups more than 95% of the probands had contacted their doctor because of the pain. In 25% of the probands the pain was positively assigned to psychological factors. A female:male ratio of 2:1 was found. CONCLUSIONS: Somatoform pain disorder (DSM-III-R) is a frequent condition. However, only about one third of these subjects is severely distressed or impaired by the pain. A clear operationalized concept of the DSM-IV criterion C 'psychological factors are judged to have an important role in the onset, severity, exacerbation or maintenance of the pain' should be provided in the further development of the diagnosis 'pain disorder' in order to make this diagnosis suitable for general population surveys.     

Specific somatoform disorder in the general population

The authors assessed the validity of the recently proposed diagnosis for specific somatoform disorder in the general population. German versions of the DSM-IV adapted Composite International Diagnostic Interview were administered to a representative sample of 4075 individuals. Multivariate analyses were used to compare impairment, life satisfaction, and use of health care. A total of 803 of 4075 subjects (19.7%) with undifferentiated somatization disorder were identified, which included 51 subjects (1.3%) who met criteria for specific somatoform disorder. Subjects with specific somatoform disorder were more impaired, had lower life satisfaction, and had higher use of health care than subjects with undifferentiated somatization disorder only. The proposed diagnosis of specific somatoform disorder demonstrated a high validity independent of comorbid depressive and anxiety disorders.     

Cannabis and cannabinoids: pharmacology and rationale for clinical use

It is now known that there are at least two types of cannabinoid receptors. These are CB1 receptors, present mainly on central and peripheral neurones, and CB2 receptors, present mainly on immune cells. Endogenous cannabinoid receptor agonists ('endocannabinoids') have also been identified. The discovery of this 'endogenous cannabinoid system' has led to the development of selective CB1 and CB2 receptor ligands and fueled renewed interest in the clinical potential of cannabinoids. Two cannabinoid CB1 receptor agonists are already used clinically, as antiemetics or as appetite stimulants. These are D 9 - tetrahydrocannabinol (THC) and nabilone. Other possible uses for CB1 receptor agonists include the suppression of muscle spasm/spasticity associated with multiple sclerosis or spinal cord injury, the relief of chronic pain and the management of glaucoma and bronchial asthma. CB1 receptor antagonists may also have clinical applications, e. g. as appetite suppressants and in the management of schizophrenia or disorders of cognition and memory. So too may CB2 receptor ligands and drugs that activate cannabinoid receptors indirectly by augmenting endocannabinoid levels at cannabinoid receptors. When taken orally, THC seems to undergo variable absorption and to have a narrow 'therapeutic window' (dose range in which it is effective without producing significant unwanted effects). This makes it difficult to predict an oral dose that will be both effective and tolerable to a patient and indicates a need for better cannabinoid formulations and modes of administration. For the therapeutic potential of cannabis or CB1 receptor agonists to be fully exploited, it will be important to establish objectively and conclusively (a) whether these agents have efficacy against selected symptoms that is of clinical significance and, if so, whether the benefits outweigh the risks, (b) whether cannabis has therapeutic advantages over individual cannabinoids, (c) whether there is a need for additional drug treatments to manage any of the disorders against which cannabinoids are effective, and (d) whether it will be possible to develop drugs that have reduced psychotropic activity and yet retain the ability to act through CB1 receptors to produce their sought-after effects.     

The effects of phototherapy in the general population

Patients with recurrent winter depression and its subsyndromal form have been reported to benefit from bright full-spectrum light (phototherapy). In order to determine whether this treatment (2 h in the morning) during winter is effective in a random sample of the general population we investigated the responses of 20 subjects with varying degrees of winter difficulties. A control group (n = 20) matched for the degree of seasonality, age, and sex was treated with dim light. Individuals were selected from a larger survey sample of the Montgomery County population (MD, U.S.A.) and were comparable to the latter in their degree of winter difficulties. Enhancement of environmental light does not, on the basis of the present study, appear to be indicated for the public at large, but rather for a subgroup of individuals with histories of winter difficulties.