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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Delta-9-tetrahydrocannabinol (THC) is the primary psycho-active ingredient in Cannabis spp., the most widely used illicit drug in the United States. THC is an exogenous agonist of the central cannabinoid receptor (CB1), one of the most abundant G-coupled receptors in the mammalian brain. Although CB1 receptors are distributed throughout the brain, they are found at very high levels in the cerebellum. Despite the variety of disturbances associated with acute cannabis intoxication, including altered short-term memory, dissociation of thoughts, motor impairments, and paranoia, among others, a reliable index of cannabinoid system function has in large part eluded scientists. Thus, there is a demand in contemporary clinical neuroscience for methods sensitive to cannabinoid system function, not only for assessing how cannabis use influences human information processing, but also to assess the involvement of the endocannabinoid system (ECS) in clinical disease and evaluate the effects of CB1-based drug therapies. The purpose of the present article, therefore, is to address this current need by integrating two separate literatures. The first literature demonstrates that the ECS mediates synaptic plasticity, specifically, long-term depression (LTD) of parallel fibers at the parallel fiber-Purkinje junction in the cerebellar cortex. The second literature suggests that LTD at this junction is necessary for the acquisition of the primary dependent variable in delay eyeblink conditioning (EBC)--the exhibition of temporally measured conditioned responses. These two literatures are integrated by proposing an updated EBC circuit that incorporates the CB1 receptor and the endogenous cannabinoids. Finally, the implications of the model is discussed in consideration of recent evidence from CB1 knockout mice, human cannabis users, and schizophrenia patients, with the expectation that translational research on the cannabinoid system will be advanced.
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PMID:Cerebellar-dependent learning as a neurobehavioral index of the cannabinoid system. 1916 90

Cannabis use has been associated with greater risk of developing psychotic-like experiences (PLEs) and psychosis. This paper aims to determine if different levels of cannabis (lifetime, regular, recent) exposure are associated with PLEs and specific PLE subscales among adolescents. Participants consisted of a community sample of 880 adolescents in Melbourne, Australia. Adolescents were administered the positive symptom scale of the Community Assessment of Psychic Experiences (CAPE) and measures of substance use and depression. Lifetime cannabis use and the frequency of cannabis use in the last year (recent use) were associated with PLEs, primarily the experience of auditory and visual hallucinations (perceptual abnormalities). Low levels of recent cannabis use were more strongly associated with PLEs than more frequent use. These findings indicate that different levels of cannabis exposure were differentially associated with PLEs and highlight the need for early detection and treatment strategies for PLEs and cannabis use in adolescents.
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PMID:The association between early cannabis use and psychotic-like experiences in a community adolescent sample. 1990 Jul 91

Cannabis is the most widely used illicit drug in the United States, yet the role of genetics in individual symptoms associated with cannabis use disorders has not been evaluated. The purpose of the present set of analyses was to describe the symptomatology and estimate the heritability of DSM-IV criteria/symptoms of cannabis dependence in a large sample of families. Participants were 2524 adults, participating in the University of California San Francisco (UCSF) Family Study of alcoholism. Seventy percent of the sample had ever used cannabis and 13.9% met DSM-IV criteria for cannabis dependence. Younger age at first cannabis use was found to be significantly associated with a shortened survival to becoming cannabis dependent. Although a greater percentage of men met criteria for cannabis dependence, women were found to demonstrate "telescoping" as indexed by a shorter survival time from initial use to dependence as compared to men. A cannabis withdrawal syndrome was identified in users, the primary symptoms of which were nervousness, appetite change, and sleep disturbance. Cannabis use (h(2)=0.31) and dependence (h(2)=0.20), age at first use, individual DSM-IV criteria for dependence, and cannabis-use associated symptoms of depression, trouble concentrating and paranoia were all found to be heritable. These findings suggest that within this population that cannabis use and dependence, as well as individual cannabis dependence symptoms have a significant heritable component, that cannabis dependence is more likely to occur when use begins during adolescence, and that the cannabis dependence syndrome includes a number of heritable untoward psychiatric side effects including withdrawal.
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PMID:Cannabis dependence in the San Francisco Family Study: age of onset of use, DSM-IV symptoms, withdrawal, and heritability. 1981 63

Marijuana, the illicit drug most widely used by adolescents, is not a benign substance. Inhalation of marijuana smoke is more harmful than tobacco smoke; cannabis smoke delivers 50% to 70% more carcinogens. Other physiological effects include decreased immune function, higher rates of cardiac arrhythmias, and documented cases of cerebellar infarction. Mood and cognitive effects of marijuana include exacerbation of depression and anxiety (including panic attacks), as well as memory problems that may persist for a month after last use. Cannabis abuse is a risk factor for psychosis in genetically predisposed people and may lead to a worse outcome of schizophrenia. The cumulative respiratory, cardiovascular, metabolic, and mental health risks of marijuana are significant and should be emphasized by nurses who work with adolescents.
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PMID:Update on marijuana. 1983 16

The influence of cannabis abuse on the severity of existing psychotic and affective symptoms is still unclear. Among 470 consecutively admitted psychotic or affective patients, 54 active (in the previous month) cannabis abusers were detected via urine tests (Sure Step TM kits; Applied Biotech Inc, San Diego, Calif) and Structured Clinical Interview for DSM-IV (SCID- IV) questionnaire. In 24 cases, substances other than cannabis were abused; 392 patients were nonabusers. All patients were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria. The following rating scales were used: Hamilton Depression Rating Scale (HAM-D-21), Positive and Negative Syndrome Scale (PANSS), and Young Mania Rating Scale (YMRS). Cannabis abusers (n = 54) were significantly younger and more frequently males than nonuser patients. In this group, there were more schizophrenic patients and fewer affective and anxiety patients (chi(2) = 11.76; P < .01). The double-diagnosed patients had more prominent psychotic symptoms than the nonusers (n = 392)-PANSS positive: 19.056 +/- 8.30 vs 16.128 +/- 8.031 (P < .02; t(446) = 2.510). The difference was statistically significant for hallucinatory behavior, excitement, grandiosity, and hostility. General PANSS scale rate of abusers was lower: 33.012 +/- 9.317 vs 37.3575 +/- 11.196 (P < .01; t = 2.727), especially for depression, anxiety, somatic concern, guilt feelings, tension, motor retardation, and volition disturbances. Rates of PANSS negative scale of abusers and nonusers were not significantly different (13.815 +/- 6.868 vs 14.983 +/- 6.446) except for lower rates of social withdrawal and stereotyped thinking for abusers. No significant difference in general level of manic symptoms (YMRS) between abusers and nonusers was observed (6.778 +/- 10.826 vs 4.910 +/- 7.754), but severity of thought/language disturbances and poor insight was found significantly higher in the abusers. Cannabis abusers are obviously less depressive (HAM-D): 5.944 +/- 10.291 vs 12.896 +/- 13.946 (P < .0005, t = 3.535). Such differences were observed in the high number of the subscales. Abusers' rates were higher (although not significantly) for paranoid symptoms and general somatic symptoms. Cannabis possibly produces some antidepressive and anxiolytic effect on psychotic and affective inpatients. The "price" of this effect is often an exacerbation of psychotic and some manic symptoms.
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PMID:Cannabis abuse and severity of psychotic and affective disorders in Israeli psychiatric inpatients. 1993 24

Cannabis use and depressive disorders are thought to impair cognitive performance and psychosocial functioning. Both disorders co-occurring may compound the negative effects of these diagnoses. In this study, the authors used the California Computerized Assessment Package as the cognitive performance measure and the Addiction Severity Index as the psychosocial functioning measure to compare individuals who were cannabis dependent and either depressed or not depressed (N= 108: 54 cannabis dependent only, 54 cannabis dependent and depressed or dysthymic). As predicted, cannabis dependent individuals with comorbid depression showed more psychosocial impairment than individuals with cannabis dependence alone. However, contrary to the authors' hypothesis, individuals who were cannabis dependent with comorbid depression showed less cognitive impairment in some California Computerized Assessment Package modules than individuals with cannabis dependence alone. Based on the authors' results, they concluded that the additive effects of cannabis dependency and depression may only be limited to psychosocial domains and may not extend to cognitive functioning.
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PMID:A comparison of psychosocial and cognitive functioning between depressed and non-depressed patients with cannabis dependence. 2063 82

The aim of this paper was to describe the psychopathological and personality profile associated with cannabis dependence in young adults and to compare it with those of non-addictive disorders and the normal population. The sample consisted of 141 cannabis-dependent subjects attending a psychiatric outpatient clinic, 140 psychiatric patients with non-addictive disorders and 140 subjects from the general population chosen to match the patient samples for age, gender and socioeconomic level. All participants were assessed with different instruments related to personality (Impulsiveness Scale, Sensation-Seeking Scale and STAI) and psychopathology (SCL-90-R, BDI, STAI and Inadaptation Scale). Patients from the clinical groups presented more anxiety and depression symptoms than healthy participants, and had more problems adjusting to everyday life, but there were no differences between the two clinical groups. Cannabis-dependent patients were specifically characterized by low educational level and by the presence of paranoid ideation; they were also more impulsive and sensation-seeking than those from the other two groups. We discuss the implications of this study for clinical practice and for further research.
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PMID:[Psychopathological symptoms and personality traits in young adult cannabis-dependent treatment seekers: A comparative study]. 2080 87

The study of cannabis use and psychopathology remains an interesting area from both academic and pragmatic perspectives. This article provides an update on the progress made in this area over the past decade or so. Psychopathology and psychiatric syndromes associated with cannabis use that have received research attention in recent years include cannabis withdrawal, cannabis and psychotic disorders (especially schizophrenia), depression, anxiety, and cognitive impairment. Status of a specific cannabis withdrawal syndrome and a specific 'cannabis psychosis' remains controversial. Current evidence indicates that there is a clinically significant association between cannabis use disorders and psychotic syndromes, depression, anxiety and possibly mild cognitive impairment. However, the nature of this association is often not clear. Several hypothesis related to the cannabis-schizophrenia association are examined. Cannabis use might be casually related to the later development of schizophrenia in an indirect way in a few heavy users, but more commonly, its use may precipitate disorders in persons who are vulnerable to developing psychosis and worsen the course of the disorder.
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PMID:Cannabis and psychopathology : update 2004. 2120 88

In the last decade, several programs for the treatment of cannabis-related disorders were developed. Until now, no information is available on the efficacy of Internet-based counseling approaches for this target group. This article describes the evaluation of "quit the shit," a web-based intervention developed to help young people to quit or reduce their cannabis use significantly. Cannabis users seeking web-based treatment were included in a two-arm controlled trial conducted on a website for drug-related information and prevention. After the baseline assessment, members of the treatment condition were randomized to a 50-day intervention program. Other trial participants were put on a waiting list. A post-test was conducted 3 months after randomization. Of all 1,292 subjects included in the trial, a total of 206 participants took part at the post-test. Per-protocol- and intention-to-treat analyses were conducted. Members of the treatment condition showed a significantly stronger reduction in cannabis use (primary outcome) than the control group. In the per-protocol analyses, moderate-to-strong effects were found for the reduction of the frequency and the reduction of the quantity of consumed cannabis. Small-to-moderate effects were observed on the secondary outcomes (use-related self-efficacy, anxiety, depression, and life satisfaction). Despite limitations concerning the interpretation of the results, the intervention seems to offer an effective treatment option for persons with cannabis-related problems.
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PMID:A controlled trial of an internet-based intervention program for cannabis users. 2165 19

Adolescence represents a critical period for brain development and the endocannabinoid system plays a crucial role in the regulation of neuronal refinement during this period. Cannabis is the most consumed drug among adolescent people and its heavy use may affect maturational refinement by disrupting the regulatory role of the endocannabinoid system. In animals, adolescent cannabinoid exposure has been reported to cause long-term impairment in specific components of learning and memory and to differentially affect emotional reactivity with milder effects on anxiety behaviour and more pronounced effects on depression-like behaviour. Moreover, adolescent exposure to cannabinoids might represent a risk factor for developing psychotic-like symptoms at adulthood. Also epidemiological studies suggest that heavy adolescent cannabis use may increase the risk of cognitive abnormalities, psychotic illness, mood disorders and other illicit substance use later in life. In conclusion, the available data point to the hypothesis that heavy cannabis use in adolescence could increase the risk of developing psychiatric disorders, especially in people who already have a vulnerability to develop a psychiatric syndrome. Only few papers have investigated the neurobiological substrates of this vulnerability, thus further studies are needed to clarify the molecular mechanisms underlying the effect of cannabis on the adolescent brain.
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PMID:Adolescent exposure to cannabis as a risk factor for psychiatric disorders. 2176 60


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