Current Psychopharmacology - Volume 2, Issue 3, 2013

Several patterns of maladaptive behaviors share their clinical features with those of substance use disorders such as tolerance, withdrawal, repeated unsuccessful attempts to cut back or quit, and interference in major areas of life function, thus gaining the name of “behavioral addictions”. Several studies showed that behavioral addictions and substance addictions share a similar pattern of brain activation during symptom provocation tasks, suggesting a common neurobiological substrate. However, despite the growing knowledge on the neurobiological underpinnings of behavioral addictions, treatment of these conditions is still controversial. Research Domain Criteria project would help in identifying circuitry involved in complex behavioral syndromes such as addiction either to substances or not-substances. The purpose of this review is to summarize current knowledge of the different pharmacological approaches to behavioral addictions. In particular, we will focus on the pharmacological treatment of pathological gambling, internet addiction and hypersexual disorder.

Modern psychobiological theory conceptualizes personality as a self-organizing, complex adaptive system involving a bi-directional interaction between heritable neurobiological dispositions to behavior (temperament) and developing concepts about self and external objects (character). Since its introduction in 1993, the Psychobiological Model of Temperament and Character (aka the Seven Factor model) has become one of the most popular, world-wide recognized models of personality structure and development. In the previous version of this review, published in this journal in 2012, we described the model in detail, especially its neurophysiological underpinnings, psychometric properties, cross cultural applicability, and clinical use in the diagnosis and treatment planning of personality disorder (PD). The Temperament and Character Inventory (TCI), a self-report test, has been developed for psychometric quantification of theoretically postulated personality traits, i.e., bio-genetic (temperament) and adaptive (character) aspects of personality. Diagnosis of PD is a 2-step process that involves both character and temperament assessment. As the first step, character is assessed to establish the severity of mal-adaptation, the core impairment shared by all subtypes of PD. As the second step, after the presence vs absence of a PD ( “casesness”) is established based on character, temperament is used for differential diagnosis. More precisely, various configurations of temperament traits distinguish specific symptomatic presentations of PD subtypes. We argue that the Seven Factor Psychobiological Model of Temperament and Character provides a theoretical framework to advance research and assessment of normal personality as well as clinical diagnosis and treatment of PD. In the original version of this review in 2012, we pointed to the correspondence between the 2-step diagnosis of PD described above and the DSM5 proposal to classify and diagnose PD. Unfortunately, due to widespread criticism of its dimensional-categorical hybrid approach, the DSM5 proposal for PDs was eliminated altogether. Instead, the DSM IV categorical approach was kept unchanged in DSM5. Here, we review the basic theoretical and clinical postulates of the Seven Factor Model and describe its application in PD. Pharmacotherapy and psychotherapy of PD are adiscussed again in some detail, including clinical management of temperament and character based on TCI scores.

This is an update to a previously published article discussing the neuropsychopharmacology of pathological gambling (PG) [1]. In the prior manuscript, we described how cortico-limbic circuitry and neurotransmitter systems (norepinephrine, serotonin, dopamine, opioids, glutamate, and gamma-aminobutyric acid (GABA)) have been implicated in PG. These systems represent potential targets for psychopharmacological treatments for PG, with opioid antagonists arguably showing the most consistent benefit in RCTs. In the past year and half since this publication was prepared, there has been one additional randomized clinical trial (RCT) published along with a single case study. Our original manuscript did not describe in detail findings from case studies or open-label studies so in addition to the new RCT data and a new case report involving naltrexone, here we describe case and open-label findings. A PubMed search was conducted using terms such as “pathological gambling treatment”, “clinical trials and gambling”, and “gambling psychopharmacology.” Using these search terms, numerous results were obtained, necessitating further search modifiers. For example, using just “pathological gambling treatment” results in over 1600 hits. In order to focus in on the search modalities, we searched within the initial results for specific phrases such as “psychopharmacology, clinical trial, medication, serotonergic, dopaminergic, etc.” in addition to searching for specific medications. Results not directly related to the treatment of pathological gambling were not included. The study of pathological gambling is relatively new. As such, our search did not exclude any studies due to age of material, but with a few exceptions, the majority of the studies discussed were published later than 2000. This resulted in 24 case studies and/or RCTs not previously included in our original review article. These findings in conjunction with our prior publication provide a comprehensive overview of controlled investigations and exploratory reports of pharmacotherapies for PG.

Several authors have hypothesized that antipsychotics could down-regulate the activation of dopamine receptors in the mesolimbic pathway, thus decreasing the occurrence and the intensity of addiction-related symptoms. We conducted a critical review of the theoretical arguments that have been published on this subject and evaluated how they compare to the published clinical data. Despite interesting findings, the effects of antipsychotics may not be as compelling as what would be theoretically expected. Thus far, antipsychotics have shown no efficacy in treating addictive disorders alone. Nevertheless, effective strategies for the use of antipsychotics against addictions are available and discussed. To treat individual vulnerability factors to addictions, such as psychiatric comorbidities (schizophrenia or bipolar disorder) that share vulnerability factors with addictive disorders and contribute to triggering addictive behaviors are among the strategies. The evidence for using antipsychotics is still the best in subjects with comorbid schizophrenia and alcohol or substance use disorder. Additionally, in some clinical situations of major impulsivity, the off-label prescription of atypical antipsychotics is worth exploring, but should be further investigated in a clinical setting.

Although it is considered rare, stimulant-induced psychosis is one of the most serious and unpleasant adverse events during attention deficit/hyperactivity disorder (ADHD) treatment. There is a need to update regularly the current state of knowledge on this topic to improve quality of care. For this reason, we reviewed relevant publications using Pubmed database, for the period 2003-2012. It came out that the amount of publications, which are predominantly case reports, on this topic are limited for this period. Previous trend of publication and state of knowledge continues. Newer atypical antipsychotics, which complicate stimulant treatment in ADHD, is an emerging dimension. We suggest more research and ongoing clinical vigilance to reach an advanced understanding of the topic.

The effects on aggression in late adolescent male rats of acute administration (via intraperitoneal injection) of 10 or 20 mg/kg of the designer drug, benzylpiperazine (BZP), were assessed in comparison with 1 or 2 mg/kg of methamphetamine (MA). The two drugs are very similar in their behavioral and neurochemical effects. Aggression was measured with the resident/intruder test of aggression which involves recording eight forms of behavior in response to an intruder rat being placed in the resident drug-treated rat’s cage. Both drugs led to often dose- and specific drug-related changes in seven of the eight measures that were indicative of decreased (rather than increased) aggression which may have arisen from hyper-vigilance, increased activity or heightened fear/anxiety i.e., decreases in an aggressive posture, chasing and sniffing the intruder and self-grooming, accompanied by increases in adopting an alert position, rearing on hind legs and avoiding the intruder. It was concluded that acute treatment with neither MA nor BZP increased aggression. As revealed in earlier research with adult rats, both drugs proved to be remarkably similar in their overall behavioral effects.

Aqueous tobacco particulate matter (TPM) is a tobacco smoke extract that contains nicotine and a number of other smoke constituents, thus TPM self-administration in rats might better represent the more complex pharmacological effects of smoke. The present study sought to examine the effects of several receptor antagonists on nicotine and TPM self-administering rats to compare underlying neurochemical systems involved in maintaining self-administration. Male Sprague Dawley rats were implanted with indwelling jugular catheters for self-administration (n=33). Rats were separated into treatment groups that self-administered nicotine (0.0 or 30.0μg/kg/inf) or cigarette TPM (with matched nicotine content) for a 20-day training period on an ascending fixed ratio schedule. Within subjects dose-response curves were produced (7.5, 15.0, 30.0 and 60.0μg/kg/inf nicotine) for both nicotine and TPM groups. Then the effects of pre-session administration of mecamylamine (0.0, 1.0 and 3.0mg/kg), SCH23390 (0.02mg/kg) and ketanserin (2.0mg/kg) were assessed at each nicotine/TPM dose. The main finding was that nicotine self-administration was attenuated by mecamylamine, SCH23390 and ketanserin pretreatment. TPM-self-administration was comparably attenuated by SCH23390 pretreatment, but was more resilient to the effects of mecamylamine, and was unaffected by ketanserin. Nicotine is the primary driver behind TPM self-administration, thus the non-nicotinic components did not affect baseline behaviour. However, the results from the antagonist trials indicate that differential mechanisms contribute to the reinforcing capacity of nicotine versus TPM.

The utility of cognitive-behavioral therapy in the treatment of acute depression has been well established. It is frequently employed with antidepressants acutely to yield greatest efficacy. While it is frequently stated that the techniques of CBT learned during acute treatment are enduring, there is little data suggesting that this is true. We studied 327 patients over a 13 year period in a community clinic who responded to one of four Selective Serotonin Reuptake Inhibitors (SSRI's) with a 50% reduction in Montgomery Asberg Score after 12 weeks treatment. SSRI's used were fluoxetine, citalopram, paroxetine and sertraline. The patients were all followed on the medication to which they responded until they either relapsed, dropped out, or terminated well (were well as of September 1, 2005 the endpoint of the study). Overall, 110 patients acutely received CBT in addition to the SSRI and 217 did not. Following acute response 35 of the 110 patients who received CBT acutely elected to continue CBT in addition to the medication and 75 did not. Overall, the group that continued CBT remained well for 49.60 months as opposed to 34.77 months for those who did not continue CBT vs 30.78 months for those who only received drug alone. Pairwise comparisons using the Scheffe show that longterm CBT results in significantly more time of stability than either acute CBT (p=.039) or drug alone (p=.001). Acute CBT and Drug Alone did not differ significantly from each other (p=0.58).. Interestingly the 75 patients who received CBT acutely but not for maintenance did not remain well longer than the 217 patients who did not receive CBT acutely (34.77 vs 30.78 p=0.58). In conclusion, CBT in addition to medication during acute treatment did not endure for the long-term. However maintenance CBT in addition to SSRI's was effective in preventing relapse.

Although there are therapeutic applications of the Anabolic Androgenic Steroids (AAS), the predominant use implies the illicit self-administration by athletes and adolescents. In this respect, AAS abuse is associated with untoward effects on brain and behavior. Exposure to supraphysiological doses of AAS leads to changes in anxiety and aggression, but their effects on cognitive functions are poorly understood. We investigated the effects of the AAS testosterone propionate (TP), acutely or chronically administered in supraphysiological doses, on memory in rats. Experiment I - Adult male Wistar rats were treated once with vehicle (Control group, n = 5) or TP (10 mg/kg, n = 5). Behavioral experiments were performed 60 minutes after the single injection, and included the evaluation of spatial working memory and recognition memory. Experiment II - The rats received repeated daily administration of vehicle (n = 6) or TP (n = 7) for 40 days. Behavioral experiments started 23 hours after the last injection. After behavioral procedures, the animals were euthanized, the blood was collected for biochemical analyses and testicles were removed and weighted. Regarding the behavioral assessment, rats chronically treated with TP presented decreased time exploring the novel object when compared to control group. Rats that were treated acutely showed no significant difference compared with control. Acute or chronic treatments with TP were not effective in promoting changes in spatial working memory. Additionally, chronic treatment with TP induced significantly increases in biochemistry marker the enzyme glutamate pyruvate transaminase (SGPT) and a reduction in testicular weight as compared with control. Even though not interfering with spatial working memory performance, AAS abuse could induce deficit on recognition memory.

Apomorphine a non-narcotic derivative of morphine acts as a dopamine agonist to produce psychostimulant effects. Currently, apomorphine is used in patients with advanced Parkinson’s disease, for the treatment of persistent and disabling motor fluctuations which do not respond to levodopa or dopamine agonists. There is growing evidence that Parkinson’s disease patients treated with apomorphine develop an addiction to their therapy. A likely explanation for this could be that the drug enhances mood and alleviates emotional distress. In the present study it is investigated by determining responses to stress in apomorphine treated animals. We find that anorexigenic and anxiogenic effects of 1st episode of immobilization stress observed in saline treated animals do not occur in apomorphine treated rats. Conversely, repeated immobilization stress of 2h/day for 5 days produces anorexia and anxiety like behavior in repeated apomorphine but not repeated saline treated animals. The present study reveals interesting differences in the effects of single and repeated administration of apomorphine on responses to single and repeated immobilization stress to support the notion that apomorphine reduces stress-induced anxiety but its long term use, like other drugs of abuse, impairs coping with stress to increase vulnerability to depression. It would suggest that stress can increase an individual's risk for substance abuse because these drugs inhibit stress perception but the converse is also true; substance abuse can increase a person's vulnerability to stress-related illnesses. The findings may help improve pharmacotherapy in Parkinson’s disease and treat depression and other stress related disorders when they coexist with addiction.