Toward a rational pharmacotherapy of comorbid substance abuse in schizophrenic patients

Peripheral and central biomarkers associated with inflammation in antipsychotic naïve first episode psychosis: Pilot studies

BACKGROUND

Elevated serum pro-inflammatory molecules have been reported in early psychosis. What is not known is whether peripheral inflammatory biomarkers are associated with CNS biomarkers. In the brain, release of pro-inflammatory molecules by microglial hyperactivity may lead to neuronal apoptosis seen in neurodegenerative disorders and account for loss of brain tissue observed in psychotic disorders. Neurochemical changes, including elevated glutamate levels, are also associated with neuroinflammation, present in early psychosis and change with antipsychotic treatment.

METHODS

Antipsychotic naïve patients with first episode psychosis (FEP) were studied as part of a collaborative project of neuroinflammation. In Study 1 we explored associations between plasma inflammatory molecules and neurometabolites in the dorsal caudate using magnetic resonance spectroscopy (1H-MRS) in N = 13 FEP participants. Study 2 examined the relationship between inflammatory molecules in the Plasma and CSF in N = 20 FEP participants.

RESULTS

In Study 1, the proinflammatory chemokine MDC/CCL22 and IL10 were significantly positively correlated with Glutamate and Glx (glutamate + glutamine) levels in the dorsal caudate. In Study 2, plasma inflammatory molecules (MIP1β/CCL4, MCP1/CCL2, Eotaxin-1/CCL11 and TNFα) were significantly correlated with CSF MIP1β/CCL4, IL10, MCP1/CCL2 and Fractalkine/CX3CL1 and symptoms ratings.

DISCUSSION

Plasma inflammatory biomarkers are elevated in early psychosis, associated with neurochemical markers as well as CSF inflammatory molecules found in neurodegenerative disorders. Future studies are needed that combine both peripheral and central biomarkers in both FEP and HC to better understand a potential neuroinflammatory subtype of psychosis likely to respond to targeted interventions.

Cognition and Related Neural Findings on Methamphetamine Use Disorder: Insights and Treatment Implications From Schizophrenia Research

Despite the prevalence of methamphetamine (meth) use disorder, research on meth is disproportionately scarce compared to research on other illicit drugs. Existing evidence highlights cognitive deficits as an impediment against daily function and treatment of chronic meth use. Similar deficits are also observed in schizophrenia, and this review therefore draws on schizophrenia research by examining similarities and differences between the two disorders on cognition and related neural findings. While meth use disorder and schizophrenia are two distinct disorders, they are highly co-morbid and share impairments in similar cognitive domains and altered brain structure/function. This narrative review specifically identifies overlapping features such as deficits in learning and memory, social cognition, working memory and inhibitory/impulse control. We report that while working memory deficits are a core feature of schizophrenia, such deficits are inconsistently observed following chronic meth use. Similar structural and functional abnormalities are also observed in cortical and limbic regions between the two disorders, except for cingulate activity where differences are observed. There is growing evidence that targeting cognitive symptoms may improve functional outcome in schizophrenia, with evidence of normalized abnormal brain activity in regions associated with cognition. Considering the overlap between meth use disorder and schizophrenia, targeting cognitive symptoms in people with meth use disorder may also improve treatment outcome and daily function.

Posttraumatic Stress Disorder Symptom Association With Subsequent Risky and Problem Drinking Initiation

OBJECTIVES

Posttraumatic stress disorder (PTSD) and unhealthy alcohol use are commonly associated conditions. It is unknown whether specific symptoms of PTSD are associated with subsequent initiation of unhealthy alcohol use.

METHODS

Data from the first 3 enrollment panels (n = 151,567) of the longitudinal Millennium Cohort Study of military personnel were analyzed (2001-2012). Complementary log-log models were fit to estimate whether specific PTSD symptoms and symptom clusters were associated with subsequent initiation of 2 domains of unhealthy alcohol use: risky and problem drinking (experience of 1 or more alcohol-related consequences). Models were adjusted for other PTSD symptoms and demographic, service, and health-related characteristics.

RESULTS

Eligible study populations included those without risky (n = 31,026) and problem drinking (n = 67,087) at baseline. In adjusted analyses, only 1 PTSD symptom-irritability/anger-was associated with subsequent increased initiation of risky drinking (relative risk [RR] 1.05, 95% confidence interval [CI] 1.00-1.09) at least 3 years later. Two symptom clusters (dysphoric arousal [RR 1.17, 95% CI 1.11-1.23] and emotional numbing [RR 1.30, 95% CI 1.22-1.40]) and 5 symptoms (restricted affect [RR 1.13, 95% CI 1.08-1.19], sense of foreshortened future [RR 1.12, 95% CI 1.06-1.18], exaggerated startle response [RR 1.07, 95% CI 1.01-1.13], sleep disturbance [RR 1.11, 95% CI 1.07-1.15], and irritability/anger [RR 1.12, 95% CI 1.07-1.17]) were associated with subsequent initiation of problem drinking.

CONCLUSIONS

Findings suggest that specific PTSD symptoms and symptom clusters are associated with subsequent initiation of unhealthy alcohol use.

A Genetic Model of Impulsivity, Vulnerability to Drug Abuse and Schizophrenia-Relevant Symptoms With Translational Potential: The Roman High- vs. Low-Avoidance Rats

The bidirectional selective breeding of Roman high- (RHA) and low-avoidance (RLA) rats for respectively rapid vs. poor acquisition of active avoidant behavior has generated two lines/strains that differ markedly in terms of emotional reactivity, with RHA rats being less fearful than their RLA counterparts. Many other behavioral traits have been segregated along the selection procedure; thus, compared with their RLA counterparts, RHA rats behave as proactive copers in the face of aversive conditions, display a robust sensation/novelty seeking (SNS) profile, and show high impulsivity and an innate preference for natural and drug rewards. Impulsivity is a multifaceted behavioral trait and is generally defined as a tendency to express actions that are poorly conceived, premature, highly risky or inappropriate to the situation, that frequently lead to unpleasant consequences. High levels of impulsivity are associated with several neuropsychiatric conditions including attention-deficit hyperactivity disorder, obsessive-compulsive disorder, schizophrenia, and drug addiction. Herein, we review the behavioral and neurochemical differences between RHA and RLA rats and survey evidence that RHA rats represent a valid genetic model, with face, construct, and predictive validity, to investigate the neural underpinnings of behavioral disinhibition, novelty seeking, impulsivity, vulnerability to drug addiction as well as deficits in attentional processes, cognitive impairments and other schizophrenia-relevant traits.

What we have learned from the Methadone Maintenance Treatment of Dual Disorder Heroin Use Disorder patients

Mental Disorders and Heroin Use Disorder (HUD) often co-occur and constitute correlated risk factors that the authors believe are best considered from a unitary perspective. In this article we review and discuss data collected by the V.P. Dole Research Group in Dual Disorder (V.P. Dole DD-RG) patients according to the following six discussion points: (1) Treatment of personality disorders during Methadone Maintenance Treatment (MMT); (2) Treatment of Mood Disorders during MMT; (3) Treatment of Anxiety Disorders during MMT; (4) Treatment of Psychotic Disorders during MMT; (5) Treatment of violence during MMT; (6) Treatment of Alcohol Use Disorder (AUD) during MMT. In treating Mood Disorder in HUD patients, we must bear in mind the interactions (potentiation and side effects) between psychopharmacology, used substances and agonist opioid medications; the use of psychiatric medications as an anti-craving drug, and the possible use of agonist and antagonist opioid medications in treating the other mental disorders. In treating chronic psychosis in HUD patients, we must consider the potentiation and side effects of antipsychotic drugs consequent on HUD treatment, worsening addiction hypophoria and inducing a more severe reward deficiency syndrome (RDS) in hypophoric patients. Violence and AUD during MMT can benefit from adequate dosages of methadone and co-medication with Sodium gamma-hydroxybutyrate (GHB). The experience of our V.P. Dole DD-RG suggests the following: (a) DD is the new paradigm in neuroscience in deepening our understanding of mental health; (b) To successfully treat DD patients a double competence is needed; (c) In managing DD patients priority must be given to Substance Use Disorder (SUD) treatment (stabilizing patients); (d) Antidepressant use is ancillary to SUD treatment; antipsychotic use must be restricted to acute phases; mood stabilizers must be preferred; any use of Benzodiazepines (BDZs) must be avoided.

A Pilot Randomized, Placebo-Controlled Trial of Glycine for Treatment of Schizophrenia and Alcohol Dependence

Objectives: The hypofunctioning of N-methyl-D-aspartate (NMDA) receptors are thought to play an important role in the pathophysiology of schizophrenia. The augmentation of the glutamatergic system through the NMDA receptor may attenuate alcohol craving and use. This study was designed to evaluate the efficacy of glycine, an agonist of the glycine B co-agonist site of the NMDA receptor on alcohol consumption and cravings as well as on negative symptoms in schizophrenia. Methods: Participants (N = 20) were given 0.8 g/kg glycine or matching placebo (provided in bottles with mixed in solution) each week for the duration of the 12-week trial. Primary outcome measures included drinking, craving for alcohol, and symptoms of schizophrenia. Cognitive functioning (attention, concentration, and memory) was also evaluated. Results: Glycine showed no benefit over placebo in the reduction of heavy drinking days or craving for alcohol over a 12-week treatment period. Nor was there an effect on negative symptoms of schizophrenia or on cognitive functioning. Conclusions: Although our study showed no beneficial effect of glycine over placebo, our results are consistent with the largest trial of glycine treatment in schizophrenia. Diagnosed schizophrenia and alcohol dependence might be more difficult to treat because of more severe psychopathology. This is the first study to date to examine an innovative treatment approach with an amino acid, glycine, as potentially acting on both alcohol intake and negative symptoms of schizophrenia.

Addiction Vulnerability: Exploring Relationships Among Cigarette Smoking, Substance Misuse, and Early Psychosis

OBJECTIVE

Smoking rates in adolescents at risk for psychosis are significantly greater than in those who are not at risk. Recent research suggests that cigarette smoking in adolescence may be a potential marker of transition to psychosis, although the exact relationship between the two remains unclear. Our aim was to examine whether tobacco smoking is a potential marker of transition to psychosis or subsequent episodes of psychosis, independently of other substance use, or alternatively whether smoking is essentially a general marker of later mental illness episodes.

METHODS

This substudy was conducted as part of an audit of a specialized early psychosis community mental health service, the Psychological Assistance Service (PAS). A multilayered audit over 10 years (January 1997 to December 2007) of PAS presentations was conducted (N = 1997), which documented baseline sociodemographic and clinical characteristics and subsequent illness episodes and service usage. Among clients with baseline smoking status information (n = 421, mean age = 18.3 years), this study examined predictors of transition to or subsequent episodes of psychosis, substance misuse, and affective disorder.

RESULTS

A recent psychosis episode at baseline and receiving ongoing treatment from PAS predicted transition to or subsequent psychosis episodes; however, baseline ultra-high-risk status was not predictive. In addition, baseline smoking/substance misuse status was a significant predictor, with smokers being twice as likely to experience a subsequent episode of psychosis, even after controlling for other baseline comorbidity. Baseline smoking status also independently predicted subsequent substance misuse episodes, but not subsequent affective disorder. Among clients experiencing post-PAS comorbid substance misuse and psychosis, the majority (80.3%) reported smoking at baseline.

CONCLUSIONS

Smoking status at service presentation appeared to function as a general proxy for addiction vulnerability among young help seekers and thereby as a potential marker for the development of severe mental illness (including psychosis) and associated health problems. Routine evaluations of presenting problems need to incorporate comprehensive assessments of early substance misuse and tobacco smoking. Adjunctive lifestyle interventions promoting smoking cessation, physical health, and well-being need to be offered in conjunction with conventional mental health interventions tailored to key presenting problems, recovery, and psychological strengthening.

Animals with a schizophrenia-like phenotype are differentially sensitive to the motivational effects of cannabinoid agonists in conditioned place preference

Cannabis is the most consumed illicit drug worldwide, but among patients with a diagnosis of schizophrenia, this consumption is higher suggesting that they are differentially sensitive to cannabis. We chose to study this problematic using a neurodevelopmental model of schizophrenia: neonatal ventral hippocampus lesions (NVHL). In a first study, we compared the locomotor response to novelty, a mild stress and two doses of amphetamine (0.75 and 1.5 mg/kg) in sham and NVHL rats at post-natal day 35 (PD35) or 56 (PD56). In a second study, we investigated the valence of the motivational effect of Delta-9-tetrahydrocannabinnol (THC, 0.5 mg/kg, i.p.) and the cannabinoid receptor agonist, WIN55,212-2 (WIN, 1 mg/kg, i.p.), using the conditioned place preference paradigm; we used a biased procedure that comprised 12 days of testing with 3 paired-conditioning. The effects of this dose of WIN were also measured on locomotor activity. Results confirmed that the adult NVHL animals displayed a stronger locomotor response to the two doses of amphetamine, but not to novelty and a mild stress. In adult NVHL, but not sham animals, WIN stimulated locomotor activity and produced a conditioned place aversion. At the dose tested, THC tended to produce an aversion in adult sham but not NVHL animals. Taken together these findings show that adult animals with a schizophrenia-like phenotype are differentially sensitive to the motivational effect of cannabinoids.

Characteristics and drinking patterns of veterans with alcohol dependence with and without post-traumatic stress disorder

Alcohol use disorders and post-traumatic stress disorder (PTSD) are highly prevalent and commonly co-occur, notably in veterans. We explored differences in the pre-treatment characteristics of veterans with alcohol dependence (AD) alone compared to those with co-occurring AD and PTSD. Veterans were recruited to participate in two different treatment studies and baseline characteristics were compared. Those with co-occurring illnesses demonstrated significantly higher pre-treatment pathology across all psychopathological domains. While those with AD alone averaged more days of drinking and had more heavy drinking days, those with co-occurring illnesses reported more drinking-related symptoms. The presence of a major depressive episode had no effect on drinking. Within the PTSD group, combat exposure was associated with increased drinking independent of the severity of PTSD symptoms. This study underscores the importance of screening for comorbidity in clinical treatment settings, and for collecting detailed drinking histories and assessing psychiatric symptoms across all domains of psychopathology.

A systematic review of psychostimulant treatment of negative symptoms of schizophrenia: challenges and therapeutic opportunities

BACKGROUND

Primary negative symptoms of schizophrenia (NSS) contribute heavily to functional disability and treatment of these symptoms continues to be a major unmet need even when the positive (psychotic) symptoms are controlled. The modified dopamine (DA) hypothesis posits that positive symptoms are associated with increased DA activity in the mesolimbic tract whereas NSS and cognitive symptoms are associated with decreased DA activity in the mesocortical (frontal) region. Several studies have reported improvement in NSS with DA agonist use, but with varying degrees of risk for triggering psychotic symptoms, especially in the absence of concurrent antipsychotic drug treatment. This article aims to examine older and newer evidence suggesting that psychostimulants may have a potential therapeutic role in the treatment of NSS together with a thorough review of the potential risks and benefits of psychostimulant administration in individuals with schizophrenia.

METHODS

A systematic search of relevant literature using electronic databases, reference lists, and data presented at recent meetings was conducted.

RESULTS

Improvement of NSS after psychostimulant administration is reviewed both in challenge and treatment paradigms with various agents such as methylphenidate, amphetamine, and modafinil or armodafinil. The literature points to evidence that, used adjunctively, DA agonists may improve NSS without worsening of positive symptoms in selected patients who are stable and treated with effective antipsychotic medications. Several areas of inadequate study and limitations are identified including small study samples, single-site trials, varying rigor of bias control, the dose and the duration of adjunctive psychostimulant administration, and the potential for development of tolerance.

CONCLUSION

Large, controlled clinical trials to further characterize effects of psychostimulants on NSS in carefully selected patients are warranted.

Movement disorders in patients with schizophrenia and a history of substance abuse

OBJECTIVE

The movement disorders acute dystonia, akathisia, Parkinsonian symptoms and tardive dyskinesia [extrapyramidal side effects (EPSs)] are recognized adverse effects of antipsychotic medication. Previous studies have indicated that substance abuse in patients with schizophrenia can worsen EPS. This study therefore investigated the relationship between drug and alcohol use and EPS in a group of patients with schizophrenia.

METHODS

Seventy patients with schizophrenia assessed for drug and alcohol use, global functioning, EPS and suicidality. Chlorpromazine equivalents were correlated to levels of EPS and substance abuse.

RESULTS

Current EPS were found in 65% of the sample despite three-quarters of the patients receiving second-generation antipsychotics. An even higher level of patients, 87%, was found to have a history of EPS. A long history of schizophrenia independently predicted presence of any EPS, particularly akathisia, controlling for history of substance abuse which was a non-significant predictor.

CONCLUSIONS

History or current use of alcohol or drug abuse did not predict EPS, except for alcohol abuse at the time of diagnosis which was associated with current akathisia. Length of illness was correlated with EPS, whereas suicidality was not linked to akathisia. Neither chlorpromazine equivalent antipsychotic dose nor whether the patient received first-generation or second-generation antipsychotic medication was significantly associated with EPS or substance abuse.

Spontaneous object recognition and its relevance to schizophrenia: a review of findings from pharmacological, genetic, lesion and developmental rodent models

RATIONALE

Spontaneous (novel) object recognition (SOR) is one of the most widely used rodent behavioural tests. The opportunity for rapid data collection has made SOR a popular choice in studies that explore cognitive impairment in rodent models of schizophrenia, and that test the efficacy of drugs intended to reverse these deficits.

OBJECTIVES

We provide an overview of the many recent studies that have used SOR to explore the mnemonic effects of manipulation of the key transmitter systems relevant to schizophrenia-the dopamine, glutamate, GABA, acetylcholine, serotonin and cannabinoid systems-alone or in combination. We also review the use of SOR in studying memory in genetically modified mouse models of schizophrenia, as well as in neurodevelopmental and lesion models. We end by discussing the construct and predictive validity, and translational relevance, of SOR with respect to cognitive impairment in schizophrenia.

RESULTS

Perturbation of the dopamine or glutamate systems can generate robust and reliable impairment in SOR. Impaired performance is also seen following antagonism of the muscarinic acetylcholine system, or exposure to cannabinoid agonists. Cognitive enhancement has been reported using alpha7-nicotinic acetylcholine receptor agonists and 5-HT(6) antagonists. Among non-pharmacological models, neonatal ventral hippocampal lesions and maternal immune activation can impair SOR, while mixed results have been obtained with mice carrying mutations in schizophrenia risk-associated genes, including neuregulin and COMT.

CONCLUSIONS

While SOR is not without its limitations, the task represents a useful method for studying manipulations with relevance to cognitive impairment in schizophrenia, as well as the interactions between them.

Pathological gambling in a psychiatric sample

OBJECTIVE

This study determines the prevalence of gambling difficulties in a consecutive sample of psychiatric inpatients and compares it with a nonpsychiatric inpatient sample. In addition, the gambling prevalence among all psychiatric disorders is analyzed.

METHOD

An observational study was conducted in psychiatric patients and sex- and age-matched nonpsychiatric patients. The psychiatric group (n = 100) included all consecutive patients admitted to the psychiatric unit of our hospital. The nonpsychiatric group (n = 100) included psychiatrically healthy inpatients from any other hospital unit. The National Opinion Research Center Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Screen for Gambling Problems was used to screen for gambling behavior.

RESULTS

Gambling difficulties were experienced by 3% (2% pathological gambling and 1% problem gambling) of nonpsychiatric inpatients and 9% (8% pathological gambling and 1% problem gambling) of psychiatric inpatients, including 6 with psychotic disorders, 1 with mood disorder, 1 with adjustment disorder, and 1 with eating disorder. There were no statistical differences in gambling prevalence between groups. In terms of comorbidity, patients with psychotic disorder had a higher prevalence of gambling problems than other psychiatric disorders (P = .045).

CONCLUSIONS

A higher prevalence of gambling disorders was found in psychiatric inpatients than in nonpsychiatric inpatients. It may be advisable for therapists to routinely assess for gambling difficulties as part of the psychiatric evaluation.

Cannabis use in children and adolescents with first episode psychosis: influence on psychopathology and short-term outcome (CAFEPS study)

OBJECTIVE

To know the prevalence of substance use and its relationship with psychopathology at onset and after six months in children and adolescents with first episode psychosis (FEP).

METHOD

110 FEP patients, aged 9-17, were assessed for substance use, and with the Positive and Negative Syndrome Scale (PANSS) and other psychopathological and general functioning scales at baseline and after a six-month follow-up.

RESULTS

Patients' substance use at baseline was: tobacco (30.9%), cannabis (29.1%), alcohol (21.8%), cocaine (8.2%), amphetamines (2.7%), LSD (1.8%) and opiates (0.90%). Six months later, there was a decrease in patients' use of cannabis (p=0.004) and other drugs, except tobacco. Patients were divided, according to their baseline cannabis use, into 32 cannabis users (CU) and 78 non-cannabis users (NCU). CU were older (p=0.002) and had higher PANSS positive scores (p=0.002) and lower PANSS negative (p<0.001), PANSS general (p=0.002) and PANSS total (p=0.007) scores than NCU. At six months, CU had significantly lower PANSS positive (p=0.010), negative (p=0.0001), general (p=0.002) and total (p=0.002) scores than NCU. When we divided CU at six months into previous CU (n=16) and current CU (n=15), previous CU had the best outcome, NCU the worst and current CU had an intermediate profile.

CONCLUSIONS

Cannabis use may be related to higher positive symptom scores for FEP patients, with greater improvement after six months for those who cease using cannabis.

Involvement of the endocannabinoid system in phencyclidine-induced cognitive deficits modelling schizophrenia

Recent advances in the neurobiology of cannabinoids have renewed interest in the association between cannabis and schizophrenia. Our studies showed that chronic-intermittent phencyclidine (PCP) treatment of rats, an animal model of schizophrenia-like cognitive deficit, impaired recognition memory in the novel object recognition (NOR) test and induced alterations in CB1 receptor functionality and in endocannabinoid levels mainly in the prefrontal cortex. In this region, we observed a significant reduction in GTPgammaS binding (-41%) accompanied by an increase in the levels of the endocannabinoid 2-AG (+38%) in PCP-treated rats, suggesting that a maladaptation of the endocannabinoid system might contribute to the glutamatergic-related cognitive symptoms encountered in schizophrenia disorders. Moreover, we evaluated the ability of the main psychoactive ingredient of marijuana, Delta9-tetrahydrocannabinol (THC), to modulate the cognitive dysfunctions and neuroadaptations in the endocannabinoid system induced by PCP. Chronic THC co-treatment worsened PCP-induced cognitive impairment, without inducing any effect per se, and in parallel, it provoked a severe reduction in the levels of the other endocannabinoid, AEA, vs. either vehicle (-73%) or PCP (-64%), whereas it reversed the PCP-induced increase in 2-AG levels. These results point to the involvement of the endocannabinoid system in this pharmacological model of cognitive dysfunction, with a potentially different role of AEA and 2-AG in schizophrenia-like behaviours and suggest that prolonged cannabis use might aggravate cognitive performances induced by chronic PCP by throwing off-balance the endocannabinoid system.

Enhanced methamphetamine self-administration in a neurodevelopmental rat model of schizophrenia

RATIONALE

Substance abuse is more prevalent among patients with schizophrenia than in the general population. The considerable overlap in neurobiological disruptions thought to underlie each condition suggests that addictive behavior may represent a primary symptom of schizophrenia.

OBJECTIVE

This study investigated drug-seeking in a neurodevelopmental animal model of schizophrenia, the neonatal ventral hippocampal lesion (NVHL) model.

MATERIALS AND METHODS

At postnatal day 7, rats received an excitotoxic ventral hippocampus lesion or a sham procedure and were trained as adults to self-administer methamphetamine (0.1 mg/kg/infusion) or respond for natural reinforcement (water or food).

RESULTS

NVHL rats were faster than shams to acquire the operant response for either drug self-administration or water reinforcement, suggesting that simple instrumental learning may be enhanced in these animals. NVHL and sham rats displayed no differences in fixed-ratio (FR) responding for either methamphetamine or food, and both groups of animals were equally sensitive to methamphetamine dose changes (0.05, 0.1, or 0.2 mg/kg/infusion). However, under a progressive-ratio (PR) schedule, NVHL animals reached significantly higher break points (NVHL 18 infusions; sham 12 infusions) for methamphetamine but not food reinforcement, suggesting enhanced motivation to acquire drug and/or elevated incentive value of the drug that did not generalize to another form of reinforcement.

CONCLUSIONS

These data indicate that developmental disruption of the hippocampus elevates rats' vulnerability to drug-seeking behavior under PR conditions. Furthermore, drug self-administration in the NVHL animal emulates addictive behavior in schizophrenia, making this model useful for investigating the mechanisms of dual diagnosis, including the neurobiological and behavioral similarities between addiction and schizophrenia.

Cannabis and schizophrenia: towards a cannabinoid hypothesis of schizophrenia

Highlighting the association between schizophrenia and Cannabis sativa and the endogenous cannabinoid receptor system, respectively, two opposite aspects are of major relevance. On the one hand, cannabis is the most widely used illegal drug. There is substantial evidence that cannabis has to be classified as an independent risk factor for psychosis that may lead to a worse outcome of the disease. This risk seems to be increased in genetically predisposed people and may depend on the amount of cannabis used. On the other hand, during the last few years, an endogenous cannabinoid receptor system (including two known cannabinoid [CB(1) and CB(2)] receptors and five endogenous ligands) has been discovered. There are several lines of evidence suggesting that, at least in a subgroup of patients, alterations in the endocannabinoid system may contribute to the pathogenesis of schizophrenia (e.g., increased density of CB(1) receptor binding and increased levels of cerebrospinal fluid endocannabinoid anandamide). Accordingly, beside the 'dopamine hypothesis' of schizophrenia, a 'cannabinoid hypothesis' has been suggested. Interestingly, there is a complex interaction between the dopaminergic and the endocannabinoid receptor system. Thus, agents that interact with the cannabinoid receptor system, such as the nonpsychoactive cannabidiol, might be beneficial in the treatment of psychosis.

Neonatal basolateral amygdala lesions affect monoamine and cannabinoid brain systems in adult rats

There is evidence for neurodevelopment disturbances in schizophrenia. In rats, a neonatal basolateral amygdala lesion induces behavioural features in adults reminiscent of the symptomatology of schizophrenia. Dopamine plays a key role in the pathogenesis of schizophrenia, and cannabis use has been implicated in the risk for developing schizophrenia. The effects of an excitotoxic, bilateral basolateral amygdala lesion on postnatal days 7 or 21 were compared when the rats were adult. The behavioural response to a novelty challenge and the level of dopamine receptors and cannabinoid receptors in the brain using in-vitro autoradiography was determined. In brain tissue punches concentrations of monoamines and metabolites were determined by high-performance liquid chromatography. The neonatal lesion, but not the later lesion induced behavioural hyperactivity and biochemical effects. The neonatal lesion reduced the density of dopamine D2-like, but not D3-, and less markely D1-like receptors and increased dopamine turnover. These effects were observed in the mesolimbic, but not in the striatal regions. In contrast, density of cannabinoid receptors was increased in the striatal, but not the mesolimbic regions of these animals. Noradrenergic neurotransmission was reduced in both regions. The present findings contribute to the idea that the neonatal basolateral amygdala lesion induces features in adults reminiscent of the neurodevelopmental disturbances in schizophrenia, with a focus on the amygdala-prefrontal cortex-nucleus accumbens circuit.

Cannabinoid receptor antagonists counteract sensorimotor gating deficits in the phencyclidine model of psychosis

Clinical and laboratory findings suggest that cannabinoids and their receptors are implicated in schizophrenia. The role of cannabinoids in schizophrenia remains however poorly understood, as data are often contradictory. The primary aim of this study was to investigate whether the cannabinoid CB1 receptor antagonists rimonabant and AM251 are able to reverse deficits of sensorimotor gating induced by phencyclidine and to mimic the 'atypical' antipsychotic profile of clozapine. The prepulse inhibition (PPI) of the startle reflex was used to measure deficits of sensorimotor gating. PPI-disruptive effects of phencyclidine and their antagonism by rimonabant, AM251, and clozapine were studied in rats. The effects of rimonabant were carefully examined taking into account dose ranges, vehicle, and route of administration. We also examined the ability of rimonabant to reduce the PPI-disruptive effects of dizocilpine and apomorphine. Rimonabant as well as AM251 significantly counteracted the phencyclidine-disruptive model of PPI, comparable to the restoring effect of clozapine; no augmentation effect was observed with rimonabant and clozapine as cotreatment. Rimonabant also significantly attenuated the PPI disruptive effects of dizocilpine and apomorphine. Taken together, our results indicate that CB1 receptor antagonists do produce 'atypical' antipsychotic profile mimicking that of clozapine in the phencyclidine disruption of sensorimotor gating. Our findings further suggest that CB1 receptor antagonism may be involved in restoring disturbed interactions between the activity of the endocannabinoid system and glutamate neurotransmitter system implied in schizophrenia.

Effectiveness of atypical antipsychotics for substance use in schizophrenia patients

OBJECTIVE

This study examined the influence of medication class (atypical antipsychotic, typical antipsychotic and no medication) and compliance on substance use outcomes for schizophrenia patients in the community.

METHOD

N=362 adults with schizophrenia-spectrum disorder were followed for 3 years in a naturalistic study with structured interviews at 6-month intervals. Multivariable time-series analysis was performed using propensity-score adjustment for selection to medication class.

RESULTS

Participants who were compliant with atypical antipsychotic medications for 90 days or more during each 6-month period were significantly less likely to use substances during the next 6-month period than patients who were compliant with typical antipsychotics or those who were not prescribed either type of medication for at least 90 days.

CONCLUSION

Atypical antipsychotics may offer an advantage in reducing substance use among schizophrenia patients. For patients to benefit from atypical antipsychotics, treatment should focus on enhancing compliance and integrating substance use treatment.

Substance abuse and schizophrenia: pharmacotherapeutic intervention

Substance use disorder is common in patients with schizophrenia and dramatically worsens their outcome. The typical antipsychotic medications, introduced more than 50 years ago, are effective for the treatment of psychosis but may have only limited efficacy in patients with these co-occurring disorders because patients continue to use substances while taking them. In preliminary studies, however, several of the atypical antipsychotic medications have shown promise for reducing alcohol and drug use in patients with schizophrenia. A neurobiological formulation is discussed, suggesting that the use of substances in patients with schizophrenia may be based on a dysfunction within the dopamine-mediated brain reward circuitry and that clozapine, in particular, may potentially ameliorate this dysfunction and lessen the desire for substance use. Medications for the treatment of alcohol use disorders, such as disulfiram, naltrexone, and acamprosate, as well as other adjunctive medications, may also be useful. Further studies are required to establish a solid evidence base of best practices for the use of medications in these patients.

Animal models and treatments for addiction and depression co-morbidity

The high rates of co-morbidity of drug addiction with depression may be attributable to shared neurobiology. Here, we discuss shared neurobiological substrates in drug withdrawal and depression, with an emphasis on changes in brain reward circuitry that may underlie anhedonia, a core symptom of depression and drug withdrawal. We explored experimentally whether clinical antidepressant medications or other treatments would reverse the anhedonia observed in rats undergoing spontaneous nicotine or amphetamine withdrawal, defined operationally as elevated brain reward thresholds. The co-administration of selective serotonin reuptake inhibitors with a serotonin-1A receptor antagonist, or the tricyclic antidepressant desipramine, or the atypical antidepressant bupropion ameliorated nicotine or amphetamine withdrawal in rats. Thus, increases in monoaminergic neurotransmission, or neuroadaptations induced by increased monoaminergic neurotransmission, ameliorated depression-like aspects of drug withdrawal. Further, chronic pretreatment with the atypical antipsychotic clozapine, that has some efficacy in the treatment of the depression-like symptoms of schizophrenia, attenuated nicotine and amphetamine withdrawal. Finally, a metabotropic glutamate 2/3 receptor antagonist reversed threshold elevations associated with nicotine withdrawal. The effects of these pharmacological manipulations are consistent with the altered neurobiology observed in drug withdrawal and depression. Thus, these data support the hypothesis of common substrates mediating the depressive symptoms of drug withdrawal and those seen in psychiatric patients. Accordingly, the anhedonic state associated with drug withdrawal can be used to study the neurobiology of anhedonia, and thus contribute to the identification of novel targets for the treatment of depression-like symptoms seen in various psychiatric and neurological disorders.

The vulnerability to alcohol and substance abuse in individuals diagnosed with schizophrenia

Individuals with schizophrenia are at increased risk for developing substance abuse disorders. Here, we consider factors that might elevate their risk for substance abuse. The tendency among schizophrenic individuals to overvalue drug-like rewards and to devalue the potential negative consequences of substance abuse may be a contributing factor to their substance abuse risk. This bias, which may partly reflect the convergence of glutamatergic and dopaminergic input to the limbic striatum, also may contribute to disadvantageous decision-making and other impulsive behavior. This propensity to seek drug-like rewards is augmented by alterations in nicotinic cholinergic, GABAergic, glutamatergic, and cannabinnoid receptor function associated with schizophrenia that increase the abuse liability of low doses of nicotine, ethanol, and perhaps cannabis, and augment the dysphoric effects of higher doses of ethanol and cannabis. The distortions in reward processing and altered response to substances of abuse also increase the likelihood that individuals with schizophrenia will self-medicate their subjective distress with abused substances. The focus on distinctions between motivation and reward with respect to substance abuse risk by schizophrenic patients suggests a need for a reconsideration of the construct of "negative symptoms" for this dually-diagnosed patient group.

A 10-year retrospective study of inpatient adolescents with schizophrenia/schizoaffective disorder and substance use

The comorbidity of schizophrenia/schizoaffective disorder and substance use is a major psychiatric concern that is associated with aggressive and suicidal behavior. This study investigated the clinical correlates and characterizes adolescent psychotic inpatients with and without comorbid substance use. We performed a retrospective study of 188 adolescent inpatients who were admitted between the years 1994 and 2004 to the inpatient unit of Geha Mental Health Center and who were diagnosed as suffering from either schizophrenia or schizoaffective disorder. The substance-using psychotic inpatients were found to have more relatives with substance-related disorders, fewer comorbid anxiety disorders, lower scores on the Brief Psychiatric Rating Scale and Hamilton Scale for Depression, higher scores on the Overt Aggression Scale, and they were more suicidal than the nonsubstance using inpatients. Adolescent inpatients with schizophrenia and schizoaffective who use substances possess differential clinical characteristics and particular correlates that justify adopting a specific approach to this high-risk clinical subgroup.

Antipsychotic drug treatment of schizophrenic patients with substance abuse disorders

BACKGROUND/AIM

In recent years, there has been a growing interest in developing adequate treatments for patients with a diagnosis of schizophrenia and a comorbid substance use disorder (SUD). In the present paper we aim to critically review published reports on the use of conventional and second-generation antipsychotics in the treatment of patients with schizophrenia and comorbid SUD, to provide clinicians with a clearer view of the pharmacological treatment of this highly prevalent dual diagnosis based upon the evidence arising from the scientific literature.

METHODS

A search of the relevant literature from Medline, PsycLIT and EMBASE databases, included in the Science Citation Index, and available up to November 2006 was conducted using the terms: 'schizophrenia', 'substance use disorder' and 'antipsychotics'.

RESULTS

While research on the use of conventional antipsychotics has remained limited, the majority of studies suggest the effectiveness of second-generation antipsychotics, particularly clozapine, for patients with schizophrenia and a comorbid substance use disorder.

CONCLUSION

In the absence of randomized controlled trials that could provide more reliable information, clinical decisions may need to rely on indirect data provided by the increasing number of case reports, open trials and retrospective studies showing a decrease in cigarette smoking, alcohol, cocaine or cannabis use and an improvement of overall psychiatric symptoms.

Atypical Antipsychotic Medication and Substance Use-Related Outcomes in the Treatment of Schizophrenia

Using national administrative data from the Department of Veterans Affairs (VA), clinical change in veterans with schizophrenia and comorbid substance abuse and dependence (n = 249) was assessed with the Addiction Severity Index. Outcomes among those switched or maintained on an atypical antipsychotic were compared with those treated with conventionals. For the entire sample and those on an atypical during the last assessment, paired t-tests showed significant decreases in the alcohol and psychological ASI scores. However, multivariate analysis showed no greater improvement in alcohol, drug, or psychological scores in individuals who were switched to (n = 33) or maintained on (n = 161) an atypical antipsychotic as compared to those who were treated with conventional at the final assessment (n = 55). Patients treated with atypical antipsychotics achieved no greater improvement in substance-related outcomes that patients who were not.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines for biological treatment of schizophrenia, Part 1: acute treatment of schizophrenia

These guide lines for the biological treatment of schizophrenia were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBO). The goal during the development of these guidelines was to review systematically all available evidence pertaining to the treatment of schizophrenia, and to reach a consensus on a series of practice recommendations that are clinically and scientifically meaningful based on the available evidence. These guidelines are intended for use by all physicians seeing and treating people with schizophrenia. The data used for developing these guidelines have been extracted primarily from various national treatment guidelines and panels for schizophrenia, as well as from meta-analyses, reviews and randomised clinical trials on the efficacy of pharmacological and other biological treatment interventions identified by a search of the MEDLINE database and Cochrane Library. The identified literature was evaluated with respect to the strength of evidence for its efficacy and then categorised into four levels of evidence (A-D). This first part of the guidelines covers disease definition, classification, epidemiology and course of schizophrenia, as well as the management of the acute phase treatment. These guidelines are primarily concerned with the biological treatment (including antipsychotic medication, other pharmacological treatment options, electroconvulsive therapy, adjunctive and novel therapeutic strategies) of adults suffering from schizophrenia.

Warum rauchen Schizophreniepatienten?

Patients suffering from schizophrenia are known to show an increased prevalence of nicotine addiction. The aim of this paper is to elucidate the relationship between schizophrenia and (chronic) use of nicotine. Nicotine seems to improve cognitive functions critically affected in schizophrenia, in particular sustained attention, focused attention, working memory, short-term memory, and recognition memory. Furthermore, several studies using evoked potentials (P50 paradigm) and prepulse inhibition of the acoustic startle reflex suggest that deficient preattentive information processing, a core feature of schizophrenia illness, is improved following treatment with nicotine. Smoking can also improve extrapyramidal secondary effects of antipsychotic medication and it induces cytochrome P4501A2, an enzyme system involved in the metabolism of several antipsychotics. There is substantial evidence that nicotine could be used by patients with schizophrenia as a "self-medication" to improve deficits in attention, cognition, and information processing and to reduce side effects of antipsychotic medication. Possible pharmacotherapeutic approaches for the regulation of abnormal neurotransmission at nicotinic acetylcholine receptors are discussed.

The CB receptor agonist WIN 55,212-2 fails to elicit disruption of prepulse inhibition of the startle in Sprague-Dawley rats

RATIONALE

A growing evidentiary body indicates cannabinoid exposure is conducive to cognitive impairment and psychotic phenomena in vulnerable individuals. In this respect, recent studies have displayed controversial results on the ability of cannabinoids to elicit sensorimotor gating alterations and attentional filtering, whose disruption is a distinctive feature of psychosis.

OBJECTIVES

The goal of this study was to investigate the effects of acute, subchronic, and chronic treatment with the synthetic CB receptor agonist WIN 55,212-2 (WIN) on prepulse inhibition (PPI) of the acoustic startle reflex (ASR), a powerful paradigm for evaluation of sensorimotor gating.

METHODS

Different groups of adult Sprague-Dawley rats were treated with 0.5, 1, and 2 mg/kg WIN (i.p.) acutely, as well as for 7 days and 21 days. All animals underwent testing 40 min after the last treatment and their evaluation was compared with that of animals treated with vehicle. In a separate group, the effects of WIN withdrawal were also analyzed, 24 h after discontinuation of a 21-day treatment.

RESULTS

No variation in PPI was detected in any of the test groups when compared with controls, whatever the dosage and the treatment.

CONCLUSIONS

These findings suggest WIN does not impair sensorimotor gating in Sprague-Dawley rats and confirm clinical evidence according to which cannabis is an unlikely causative of psychosis among non-vulnerable individuals. Nonetheless, since in other studies the same compound was shown to induce PPI alterations in Wistar rats, our results are also suggestive that genetic differences might be critical for the development of cannabis-induced cognitive disorders.

New medication strategies for comorbid substance use and bipolar affective disorders

Comorbidity of substance abuse disorders (SUD) with bipolar disorders (BPD) is a serious treatment problem. Childhood BPD can be further complicated by comorbidity with attention-deficit/hyperactivity disorder (ADHD) and later SUD during adolescence. The aim of this article is to review the literature on pharmacotherapies for these patients. Developing the ideal pharmacotherapy for BPD and SUD can be informed by the role of gamma-aminobutyric acid (GABA) in the neurobiology of SUD. This ideal pharmacotherapy would have several key characteristics. These characteristics include treating the BPD, relieving withdrawal symptoms, and preventing relapse to SUD. The ideal medication should have low abuse liability, require infrequent dosing, be well tolerated, and have few side effects. A medication approaching this ideal is the GABA enhancer valproate. Adding atypical antipsychotic agents might not improve valproate's efficacy, but combining GABA medications with selective serotonin reuptake inhibitors holds promise for SUD with depression. Pemoline might be the best option for minimizing the risk of SUD complicating comorbid ADHD with BPD.

[Dual diagnosis of psychosis and addiction. From principles to practice]

The prevalence of comorbidity of psychosis and substance abuse/addiction has been on the rise during the last 10-20 years. Meanwhile, dual diagnosis patients (DD patients) represent a large core group among patients with schizophrenia, and they are difficult to treat. Biological, psychological, and social factors may account for the comorbidity, and the single factors may interact with each other. DD patients tend to have poor compliance and unfavorable outcomes with frequent psychotic relapses and hospitalizations. Efficient treatment models integrate traditional psychiatric therapy and therapy of addiction and modify or adjust the two components to each other. The most successful programs offer integrated treatment for both disorders in one setting. These programs focus on outpatient treatment, they offer pharmacotherapy, motivation therapy, psychoeducation, cognitive-behavioral therapy, and family interventions, and they can achieve significant improvements of social adjustment and decreases of substance use.

Quetiapine in the successful treatment of schizophrenia with comorbid alcohol and drug dependence: a case report

BACKGROUND

Excluding nicotine and caffeine dependence, almost 50% of individuals with schizophrenia also meet the criteria for substance abuse or dependence. Comorbid drug abuse presents complications to the effective treatment of these patients because they have increased psychotic symptoms and poorer treatment compliance.

CASE REPORT

This report describes thecase of a young man with schizophrenia and comorbid alcohol and cocaine abuse who was successfully treated with quetiapine. The patient was previously treated with olanzapine and developed priapism, which required emergency medical treatment.

CONCLUSIONS

The possible utility of atypical antipsychotics in the treatment of patients with schizophrenia and comorbid substance abuse needs to be confirmed in clinical trials.

Pharmacotherapy for schizophrenia and co-occurring substance use disorders

Research on the optimal pharmacotherapy for people with schizophrenia and co-occurring substance use disorders remains in its infancy. This report reviews existing data and provides an update on recent research. The confluence of findings is consistent with a model of a reward dysfunction inherent in the neuropathology of schizophrenia, leading to a heightened vulnerability of people with schizophrenia to substance use disorders. Studies indicate that patients with dual disorders have difficulty tolerating conventional antipsychotics, have higher rates of medication nonadherence, and have greater impulsivity and sensation seeking. Limited evidence suggests that clozapine treatment may be associated with reduced substance abuse, with weaker evidence suggesting that other novel antipsychotics may have similar, but potentially less potent, effects. Controlled trials to test the effects of these medications are underway. A number of recent studies indicate that bupropion can facilitate reduced tobacco smoking among patients with schizophrenia. The preferential use of novel antipsychotics, a lower threshold for prescription of clozapine, the use of bupropion for smoking cessation, careful monitoring of compliance, and possible use of other medications for substance use disorders when indicated are recommended in pharmacologic management for people with co-occurring substance use disorders and schizophrenia.

Substance misuse in patients with schizophrenia: a primary care guide

Smoking presents a substantial health and economic burden to people with schizophrenia. Comorbid use of other substances is common, under-recognised, and associated with a number of serious adverse consequences, such as psychotic relapse and poorer social outcomes. All patients with schizophrenia need to be screened for substance misuse. Effective interventions involve integrated, modified pharmacological and psychosocial strategies.

Clinical variables related to suicide attempts in schizophrenic patients: a retrospective study

In this study, we investigated the possible association between clinical or pharmacological variables and suicidal behavior in a sample of chronic schizophrenia or schizoaffective disorder patients. One hundred and three patients with a DSM-III-R diagnosis of chronic schizophrenia or schizoaffective disorder were studied. The sample was subdivided in two subsamples according to the presence/absence of suicidal attempts lifetime. The main demographic and clinical variables retrospectively collected were analyzed and compared between the two groups. Attempters had a significantly higher rate of nicotine abuse or dependence (chi-square=3.900, df=1, p<0.05, Odds Ratio (O.R.)=3.4), were more likely to have or have had lifetime major depressive episodes (chi-square=10.258, df=1, p<0.002, O.R.=6.5), were more likely to have a duration of untreated psychosis (DUP) > or =1 year (chi-square=6.228, df=1, p<0.02, O.R.=12.5), and were more frequently prescribed typical antipsychotics (chi-square=3.979, df=1, p<0.05, O.R.=6.5) than patients without suicidal attempts lifetime. Further investigations on larger samples and with prospective designs are warranted, particularly with respect to the role of early intervention and atypical antipsychotic treatment in reducing suicide risk in schizophrenic patients.

Alcohol and cannabis use in schizophrenia: effects of clozapine vs. risperidone

BACKGROUND

Alcohol and cannabis use disorders worsen the course of schizophrenia. While the typical antipsychotics are of limited value in controlling substance use in schizophrenic patients, previous studies suggest that the novel antipsychotic clozapine (CLOZ) may decrease their substance use. We describe a retrospective study of the effects of the novel antipsychotics risperidone (RISP) and clozapine on alcohol and cannabis use in patients with schizophrenia or schizoaffective disorder and comorbid alcohol and/or cannabis use disorder.

METHOD

This study involved retrospective assessment of abstinence (cessation of alcohol and cannabis use) in 41 patients treated with either risperidone (n=8) or clozapine (n=33) for at least 1 year. In 32 of these 41 patients, information was available on whether abstinence occurred during the 1-year period.

RESULTS

Abstinence rates were significantly higher in patients treated with clozapine than in those treated with risperidone (54% vs. 13%, p=0.05). The nine patients treated for at least 1 year, but excluded from the analysis because time of cessation of use was not known, had all stopped alcohol/cannabis use during clozapine treatment.

DISCUSSION

While the limitations of this retrospective study must be recognized, the data suggest that comorbid patients treated with clozapine are more likely to abstain from alcohol and cannabis use than are those treated with risperidone. Further prospective studies will be required to confirm these intriguing results.

Detection and management of comorbidity in patients with schizophrenia

Approximately half of patients with schizophrenia have at least one comorbid psychiatric or medical condition, worsening prognosis and contributing to the high rate of morbidity and mortality. Depression is associated with suicide, the leading cause of premature death in patients with schizophrenia; obsessive-compulsive symptoms may worsen prognosis; alcohol and substance use disorders are associated with a poor outcome; and comorbid medical conditions, including cardiac and pulmonary disease, infectious diseases, diabetes, hyperlipidemia, hypogonadism, and osteoporosis, are often underrecognized and undertreated. The new generation of antipsychotic medications has improved the potential outcome of patients with schizophrenia. Providing optimal treatment for patients and fully realizing the potential of these new agents require focused attention on detection, recognition, and treatment of comorbid psychiatric and medical conditions in patients with schizophrenia.

Clinical aspects of substance abuse in persons with schizophrenia

OBJECTIVE

To review the current knowledge on the problem of psychoactive substance abuse by persons with schizophrenia, with particular attention to issues of direct relevance to clinical practice.

METHOD

The author examined the literature from the last 2 decades and data from studies in which he was involved.

RESULTS

Schizophrenia sufferers show an elevated liability for substance abuse. Such comorbidity may derive from self-medication attempts, a common neuropathology for addiction and schizophrenia, the psychotogenic properties of certain drugs, or the influence of environmental factors. Among schizophrenia patients receiving treatment, substance misuse is associated with more severe symptoms and poorer therapeutic response. The presence of a chronic psychosis impedes treatment of the substance problem in traditional, nonpsychiatric addiction programs. Better outcomes are observed in integrated therapy services, where patients receive appropriate care for both conditions.

CONCLUSION

Dual-pathology patients need comprehensive care with appropriate pharmacotherapy and psychosocial interventions. This treatment can be best provided within the context of a continuing care psychiatric service.

Substance misuse in patients with schizophrenia: epidemiology and management

Substance misuse in individuals with schizophrenia is very common, especially in young men, in communities where use is frequent and in people receiving inpatient treatment. Problematic use occurs at very low intake levels, so that most affected people are not physically dependent (with the exception of nicotine). People with schizophrenia and substance misuse have poorer symptomatic and functional outcomes than those with schizophrenia alone. Unless there is routine screening, substance misuse is often missed in assessments. Service systems tend to be separated, with poor inter-communication, and affected patients are often excluded from services because of their comorbidity. However, effective management of these disorders requires a fully integrated approach because of the close inter-relationship of the disorders. Use of atypical antipsychotics may be especially important in this population because of growing evidence (especially on clozapine and risperidone) that nicotine smoking, alcohol misuse and possibly some other substance misuse is reduced. Several pharmacotherapies for substance misuse can be used safely in people with schizophrenia, but the evidence base is small and guidelines for their use are necessarily derived from experience in the general population.

Neurodevelopmental liabilities of substance abuse

The perinate is particularly risk-prone to chemical species which have the potential of inducing neuronal apoptosis or necrosis and thereby adversely altering development of the brain, to produce life-long functional and behavioral deficits. This paper is an overview for many substances of abuse, but the purview is much more broadened by the realization that even elevated levels of estrogens and corticosteroids in the pregnant mother can act as neuroteratogens, by passing via the placenta and altering neural development or inducing apoptosis in the perinate. Finally, therapeutic risks of anesthetics are highlighted, as these too induce neuronal apoptosis in the neonate by either blocking N-methyl-D-aspartate receptors or by acting as gamma-aminobutyric acid agonists. By understanding the mechanisms involved it may ultimately be possible to interrupt the mechanistic scheme and thereby prevent neuroteratological processes.

Neuroadaptations to chronic exposure to drugs of abuse: relevance to depressive symptomatology seen across psychiatric diagnostic categories

Depressive symptomatology is expressed across a wide spectrum of psychiatric disorders including major depression and schizophrenia. Further, depressive symptomatology is also observed in individuals undergoing withdrawal from chronic exposure to various drugs of abuse including cocaine, amphetamine and nicotine. The negative affective state associated with drug withdrawal is phenomenonologically similar to that observed in depressed and schizophrenia patients suggesting that common underlying pathophysiological deficits may be involved in the depressive symptomatology seen across these different psychiatric disorders. The aim of the present review is to examine clinical and preclinical evidence in support of a common neurobiological substrate mediating the negative affect associated with different psychiatric illnesses. First, clinical and epidemiological data are presented demonstrating the high comorbidity between nicotine and psychostimulant dependence, and depression or schizophrenia. It is hypothesized that drug-use may represent an attempt to self-medicate an underlying negative affective state present in depressed and schizophrenia patients. Second, preclinical findings are presented that demonstrate common neurochemical deficits in drug withdrawal and depression. Taken together, these clinical and preclinical data support the hypothesis that common neurobiological substrates may mediate the depressive state observed across psychiatric diagnostic categories. Therefore, it is proposed that the study of drug-induced depressions in laboratory animals may have heuristic value in identifying the mechanisms underlying the depressive symptomatology associated not only with drug withdrawal but also major depression and schizophrenia.

Substance abuse among patients with schizophrenia

Substance use in the general population is a significant public health problem. Problems associated with substance use are aggravated by concomitant psychiatric illness, particularly schizophrenia and schizoaffective disorder. Although there is a general agreement on the need to address this problem, a wide range of opinions exists on exactly what is the best modality. In this article, we provide a brief overview of the etiology and consequences of substance use in individuals with schizophrenia, followed by a more detailed review of pharmacological and psychotherapeutic trends in the treatment of this population. Research studies indicate that, while some evidence supports the self-medication hypothesis, individuals with schizophrenia or schizoaffective disorder frequently use substances for the same reasons and in the same manner as the general population. In the pharmacotherapy section, we briefly discuss the rationale for current medication strategies, their efficacy, and directions for future research. This is followed by an assessment of current psychotherapeutic interventions, their limitations, and potential modifications to improve treatment outcome. The research literature suggests that integrated treatment and well-tailored interventions that take into account psychosocial factors and motivation offer the most promise for the future. More controlled trials are necessary to validate this hypothesis.

Comorbid non-alcohol substance misuse among people with schizophrenia: epidemiological study in central London

BACKGROUND

Few epidemiological studies have assessed the extent and nature of comorbid non-alcohol substance misuse in people with schizophrenia in the community in the UK.

AIMS

To study the extent and nature of comorbid non-alcohol substance misuse in people with schizophrenia in central London.

METHOD

Subjects were identified in an epidemiological census survey of South Westminster. Standardised assessment of each subject included demographic data, ratings of mental state and movement disorder and questioning about drug and alcohol misuse.

RESULTS

Individuals with schizophrenia or related psychoses were identified (n=352) and 57 (16%) reported a lifetime history of non-alcohol substance misuse. Age and gender were the main variables relevant to the extent and pattern of misuse. Self-reported non-alcohol substance misuse showed no significant relationship with a range of outcome measures.

CONCLUSIONS

The high proportion of subjects reporting non-alcohol substance misuse is comparable with figures from the USA. The reports of lifetime misuse most commonly referred to cannabis, psychostimulants, LSD, opiates and anticholinergics. Misuse was concentrated in those younger than 36 years and was reported more often by males.

A neurobiological basis for substance abuse comorbidity in schizophrenia

It is commonly held that substance use comorbidity in schizophrenia represents self-medication, an attempt by patients to alleviate adverse positive and negative symptoms, cognitive impairment, or medication side effects. However, recent advances suggest that increased vulnerability to addictive behavior may reflect the impact of the neuropathology of schizophrenia on the neural circuitry mediating drug reward and reinforcement. We hypothesize that abnormalities in the hippocampal formation and frontal cortex facilitate the positive reinforcing effects of drug reward and reduce inhibitory control over drug-seeking behavior. In this model, disturbances in drug reward are mediated, in part, by dysregulated neural integration of dopamine and glutamate signaling in the nucleus accumbens resulting form frontal cortical and hippocampal dysfunction. Altered integration of these signals would produce neural and motivational changes similar to long-term substance abuse but without the necessity of prior drug exposure. Thus, schizophrenic patients may have a predilection for addictive behavior as a primary disease symptom in parallel to, and in many, cases independent from, their other symptoms.

MACS-II: does coping enhance subjective control over psychotic symptoms?

OBJECTIVE

Associations between subjective experience of control and the use of self-initiated coping strategies were examined in patients with psychotic symptoms.

METHOD

Twenty-three patients were interviewed to assess (i) the subjective experience of distress with and control over symptoms and (ii) the coping strategies used.

RESULTS

There was a positive association between coping type and control (OR = 1.07, 95% CI: 1.03-1.12). Active coping strategies had the strongest association with experience of control (active problem-solving: OR = 1.41 95% CI: 1.18-1.68; active problem-avoiding: OR = 1.45 95% CI: 1.18-1.68). Symptomatic coping was negatively associated with control (OR = 0.40, 95% CI: 0.30-0.55), but was the most frequently used strategy. Depressive symptoms were associated with the highest number of coping strategies.

CONCLUSION

Coping strategies differ in the degree and direction of associated subjective control, and symptoms differ in the degree with which coping is mobilized. Assessment of coping strategies may be useful as a prelude to psychological therapy.

Substance abuse in schizophrenia: a review of the literature and a study of correlates in Sweden

The purpose of the current study is twofold: (a) to provide an overall synthesis of recent research on substance abuse in schizophrenia and (b) to present findings in a Swedish patient sample. Studies conducted since 1990 have found a wide range of abuse prevalence rates, with male gender and younger age as primary correlates. Less certainty exists regarding substance abuse as an independent risk factor for schizophrenia and its further impact on illness course. In a sample of 87 patients attending a psychiatric clinic in Malmö, lifetime prevalence of substance abuse was 48.3%, with abuse debut primarily preceding first contact for psychotic symptoms. Significant correlates of abuse were male gender, family history of substance abuse, and increased rates of hospitalization and criminality, with poorer outcome found in previous as well as current abusers. Alcohol abuse, either solely or in combination with other substances, was the main type of substance abuse. Although the specific factors (social, behavioural, genetic) that predispose schizophrenic patients to substance abuse remain unclear, the predominantly male profile of abusers might suggest a link between substance abuse and the poorer clinical outcome frequently observed, especially in male schizophrenic patients.