Nomifensine maleate in adult attention deficit disorder

Attention-Deficit Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) is the most common of the childhood psychiatric disorders, with a prevalence rate of up to 20%, and is probably genetically transmitted. ADHD is characterized by impulsive behavior, hyperactivity, and decreased attention span. It is often extremely disruptive to the afflicted individuals social interactions and school performance. Therapeutic approaches to ADHD should be multimodal, including medications, family, and educational therapies. The pathophysiology of ADHD is not yet fully understood. Catecholoamines are believed to play a significant role with serotonin in an adjunctive role. Pathophysiological theories are supported by useful drug therapies that are known to affect dopamine and norepinephrine metabolism. Stimulants remain the drugs of choice, with methylphenidate most commonly used. Dextroamphetamine and pemoline are also effective. The rational use of these drugs is discussed. Antidepressants are second-line drug therapies; their usefulness is most apparent in patients who have high levels of anxiety and/or depression. Other potentially useful medications, including clonidine and the antipsychotics, are discussed. Adult populations can also express ADHD; treatment is similar to that used in children. Overall, ADHD is an important illness with significant morbidity. Pharmacotherapy is highly effective for its treatment and forms the cornerstone of therapy. This review of ADHD seeks to promote a greater understanding of this disorder and its appropriate drug therapy.

Antidepressant drug development: Focus on triple monoamine reuptake inhibition

Many patients with major depressive disorder (MDD) only partially respond, and some have no clinically meaningful response, to current widely used antidepressant drugs. Due to the purported role of dopamine in the pathophysiology of depression, triple-reuptake inhibitors (TRIs) that simultaneously inhibit serotonin (5-HT), norepinephrine (NE) and dopamine reuptake could be a useful addition to the armamentarium of treatments for MDD. A TRI should more effectively activate mesolimbic dopamine-related reward-networks, restore positive mood and reduce potent 5-HT reuptake blockade associated "hypodopaminergic" adverse effects of decreased libido, weight gain and "blunting" of emotions. On the other hand, dopaminergic effects raise concern over abuse liability and TRIs may have many of the cardiovascular effects associated with NET inhibition. Several clinical development programs for potential TRI antidepressants have failed to demonstrate significantly greater efficacy than placebo or standard of care. Successful late-stage clinical development of a TRI is more likely if experimental research studies in the target population of depressed patients have demonstrated target engagement that differentially and dose-dependently improves assessments of reward-network dysfunction relative to existing antidepressants. TRI treatment could be individualized on the basis of predictive markers such as the burden of decreased positive mood symptoms and/or neuroimaging evidence of reward network dysfunction. This review focuses on how the next generation of monoamine-based treatments could be efficiently developed to address unmet medical need in MDD.

Development of potent dopamine-norepinephrine uptake inhibitors (DNRIs) based on a (2S,4R,5R)-2-benzhydryl-5-((4-methoxybenzyl)amino)tetrahydro-2H-pyran-4-ol molecular template

Current therapy of depression is less than ideal with remission rates of only 25-35% and response rates of 45-60%. It has been hypothesized that a dysfunctional dopaminergic system in the mesocorticolimbic pathway in depressive disorder may lead to development of anhedonia associated with loss of pleasure and interest along with loss of motivation. The current antidepressants do not address dopamine dysfunction which might explain their low efficacy. In this report, we have described an SAR study on our pyran-based triple reuptake inhibitors (TRIs) which are being investigated as the next-generation antidepressants. In the present work we demonstrate that our lead TRIs can be modified with appropriate aromatic substitutions to display a highly potent SSRI profile for compounds 2a and 4a (Ki (SERT); 0.71 and 2.68nM, respectively) or a potent DNRI profile for compounds 6b and 6h (Ki (DAT/NET); 8.94/4.76 and 13/7.37nM, respectively). Compounds 4g-4i exhibited potencies at all three monoamine transporters. The results provide insights into the structural requirements for developing selective dual- and triple-uptake inhibitors from a unique pyran molecular template for an effective management of depression and related disorders.

An update on the pharmacotherapy of attention-deficit/hyperactivity disorder in adults

Adults with attention-deficit/hyperactivity disorder (ADHD) are more frequently presenting for diagnosis and treatment. Medication is considered to be appropriate among available treatments for ADHD; however, the evidence supporting the use of pharmacotherapeutics for adults with ADHD remains less established. In this article, the effectiveness and dosing parameters of the various agents investigated for adult ADHD are reviewed. In adults with ADHD, short-term improvements in symptomatology have been documented through the use of stimulants and antidepressants. Studies suggest that methylphenidate and amphetamine maintained an immediate onset of action, whereas the ADHD response to the nonstimulants appeared to be delayed. At a group level, there appears to be some, albeit not entirely consistent, dose-dependent responses to amphetamine and methylphenidate. Generally speaking, variability in diagnostic criteria, dosing parameters and response rates between the various studies was considerable, and most studies were of a relatively short duration. The aggregate literature shows that the stimulants and catecholaminergic nonstimulants investigated had a clinically significant beneficial effect on treating ADHD in adults.

A one year trial of methylphenidate in the treatment of ADHD

OBJECTIVE

To determine the effects of long-term methylphenidate treatment on symptom severity and social adjustment in adult ADHD.

METHOD

Adults (n = 116) meeting operational diagnostic criteria for ADHD (the "Utah Criteria") entered a randomized double-blind crossover trial of methylphenidate and placebo. Participants who improved on immediate-release methylphenidate entered a 12-month, open-label trial. Outcomes were assessed using the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS), Clinical Global Impression-Improvement (CGI-I), global assessment of functioning (GAF), and the Weissman Social Adjustment Scale (WSAS).

RESULTS

In the double-blind trial more patients improved (50% reduction of symptoms) receiving methylphenidate (74%) than placebo (21%, p = .001). During the open-label trial, symptom severity decreased 80% from baseline, and the WSAS decreased >50% in all subscales. The average GAF improved significantly (p < .0001).

CONCLUSION

ADHD adults, who responded to methylphenidate in a short-tem, placebo-controlled trial, responded to long-term treatment with marked improvements in ADHD symptoms and psychosocial functioning.

Role of aberrant striatal dopamine D1 receptor/cAMP/protein kinase A/DARPP32 signaling in the paradoxical calming effect of amphetamine

Attention deficit/hyperactivity disorder (ADHD) is characterized by inattention, impulsivity, and motor hyperactivity. Several lines of research support a crucial role for the dopamine transporter (DAT) gene in this psychiatric disease. Consistently, the most commonly prescribed medications in ADHD treatment are stimulant drugs, known to preferentially act on DAT. Recently, a knock-in mouse [DAT-cocaine insensitive (DAT-CI)] has been generated carrying a cocaine-insensitive DAT that is functional but with reduced dopamine uptake function. DAT-CI mutants display enhanced striatal extracellular dopamine levels and basal motor hyperactivity. Herein, we showed that DAT-CI animals present higher striatal dopamine turnover, altered basal phosphorylation state of dopamine and cAMP-regulated phosphoprotein 32 kDa (DARPP32) at Thr75 residue, but preserved D(2) receptor (D(2)R) function. However, although we demonstrated that striatal D(1) receptor (D(1)R) is physiologically responsive under basal conditions, its stimulus-induced activation strikingly resulted in paradoxical electrophysiological, behavioral, and biochemical responses. Indeed, in DAT-CI animals, (1) striatal LTP was completely disrupted, (2) R-(+)-6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF 81297) treatment induced paradoxical motor calming effects, and (3) SKF 81297 administration failed to increase cAMP/protein kinase A (PKA)/DARPP32 signaling. Such biochemical alteration selectively affected dopamine D(1)Rs since haloperidol, by blocking the tonic inhibition of D(2)R, unmasked a normal activation of striatal adenosine A(2A) receptor-mediated cAMP/PKA/DARPP32 cascade in mutants. Most importantly, our studies highlighted that amphetamine, nomifensine, and bupropion, through increased striatal dopaminergic transmission, are able to revert motor hyperactivity of DAT-CI animals. Overall, our results suggest that the paradoxical motor calming effect induced by these drugs in DAT-CI mutants depends on selective aberrant phasic activation of D(1)R/cAMP/PKA/DARPP32 signaling in response to increased striatal extracellular dopamine levels.

Additive subthreshold dose effects of cannabinoid CB(1) receptor antagonist and selective serotonin reuptake inhibitor in antidepressant behavioral tests

The main clinically used antidepressant drugs are selective monoamine reuptake inhibitors, including selective serotonin reuptake inhibitors (citalopram, sertraline), selective dopamine reuptake inhibitor (nomifensine) and selective noradrenaline reuptake inhibitor (reboxetine), but they have various side effects. Because cannabinoid CB(1) receptor antagonists (SR141716A, AM251) enhance monoamine release, they might be beneficial in the therapy of affective disorders. We hypothesized that the use of monoamine reuptake inhibitors in combination with cannabinoid CB(1) receptor antagonists would allow a lower dose of monoamine reuptake inhibitors to be used in the therapy of depression, thereby reducing or eliminating the side effects. To test this hypothesis, we examined the combination of SR141716A or AM251 with citalopram, sertraline, nomifensine or reboxetine at subthreshold doses to see whether these combinations would show an additive effect in the forced swimming test and the tail suspension test with mice. Subthreshold doses of cannabinoid CB(1) receptor antagonist and selective serotonin reuptake inhibitors, which separately had no effect on the immobility of mice in the tests, showed a clear effect when the drugs were administered at 40 and 30 min, respectively, before the tests, without any change of motor activity. Therefore, the use of subthreshold doses of these agents in combination might be useful to enhance mainly serotonergic neurotransmission, and to reduce or eliminate the side effects of citalopram and sertraline.

Drug Therapy for Adults with Attention-Deficit Hyperactivity Disorder

Practitioners are increasingly called upon to diagnose and treat attention deficit hyperactivity disorder (ADHD) in adults. Although the use of pharmacotherapy in children with ADHD is well studied, the use of drugs for the treatment of adults with ADHD remains less well established.A systematic review of the literature identified 15 studies (n = 482 patients) of stimulants, and 27 studies of nonstimulant medications (n = 1179 subjects) including antidepressants, norepinephrine reuptake inhibitors, antihypertensive agents, amino acids and wake-promoting agents for the treatment of ADHD in adults. Controlled clinical trials in adults showed that stimulants, antidepressants and norepinephrine reuptake inhibitors demonstrated significant short-term improvements in ADHD symptoms compared with placebo. The two longer term trials with methylphenidate in adults confirmed the ongoing effectiveness and tolerability of stimulants. The response to amphetamine and methylphenidate appears to be dose-dependent. Methylphenidate and amphetamine had an immediate onset of action, whereas responses to pemoline, antidepressants and norepinephrine reuptake inhibitors appeared delayed. Controlled data on nicotinic/cholinergic compounds appear promising. Considerable variability was found in the diagnostic criteria for ADHD in adults, drug dosages and response rates between the various studies. Under controlled conditions, the aggregate literature comprised mainly of short-term studies, shows that stimulants, norepinephrine reuptake inhibitors and specific antidepressants had clinically and statistically significant beneficial effects in the treatment of ADHD in adults. Cholinergic agents appear promising. Further studies are necessary to evaluate the long-term effectiveness and tolerability of various agents, functional and neuropsychological outcomes, and the use of various agents in specific subgroups of adults with ADHD.

A review of the pharmacotherapy of adults with attention-deficit/hyperactivity disorder

OBJECTIVE

Despite the increasing recognition of attention deficit hyperactivity disorder (ADHD) in adults, the use of pharmacotherapeutics remains less established.

METHODS

A systematic review of the literature identified 15 studies (N = 435 subjects) of stimulants, and 22 studies of non-stimulant medications (N = 421 subjects) including antidepressants, antihypertensives, amino acids, and wake-promoting agents for the treatment of ADHD in adults.

RESULTS

Studies with stimulants and antidepressants demonstrated significant short-term improvement in ADHD symptoms compared to placebo in adults. Methylphenidate (MPH) and amphetamine had an immediate onset of action whereas the ADHD response to pemoline and antidepressants appeared delayed. The response to amphetamine and MPH appears to be dose-dependent. Controlled data on nicotonic and noradrenergic compounds appear promising. There was considerable variability in diagnostic criteria, dosing parameters, and response rates between the various studies.

CONCLUSIONS

Under controlled conditions, the aggregate literature shows that the stimulants and noradrenergic antidepressants had a clinically and statistically significant beneficial effect on treating ADHD in adults.

A review of the effects of dopaminergic agents on humans, animals, and drug-seeking behavior, and its implications for medication development. Focus on GBR 12909

Medication development for cocaine abuse has focused on potential mechanisms of action related to the abuse of cocaine. The hypothesis that mesolimbic dopamine (DA) is the key neurochemical mediator of cocaine's addictive and reinforcing effects is well supported by a wide variety of data from animal studies. On the other hand, medications that increase DA or block its action in humans can produce effects that appear incompatible with this hypothesis. This article reviews these incompatibilities between animal and human data with a focus on the DAergic actions of drugs, including DA reuptake inhibitors, direct DA agonists, DA increasers, and DA antagonists. Possible reasons for these discrepancies are discussed, and the potential role of high-affinity DA uptake inhibitors, such as GBR12909, for pharmacotherapies for treating cocaine addiction in humans is likely to come from understanding its mechanisms of action, it is clear that further research on the effects of cocaine in humans and animals will be critical to the medication development effort.

Pharmacotherapy of adult attention deficit/hyperactivity disorder: a review

Adult attention deficit/hyperactivity disorder (ADHD) is an increasingly recognized disorder with associated psychiatric comorbidity and impairment. Although pharmacotherapy serves an important role in treating ADHD and other concurrent psychiatric disorders in children and adolescents, the use of pharmacotherapeutics for adults with ADHD remains less established. In this report, the effectiveness and dosing parameters of the various agents investigated for adult ADHD are reviewed. A systematic review of the available literature identified 7 studies (N = 193 subjects) of psychostimulants and 10 studies of nonstimulant medications (N = 167 subjects) including antidepressants, antihypertensives, and amino acids for the treatment of ADHD in adults. The majority of double-blind investigations were with the psychostimulants, with the nonstimulant agents, generally antidepressants, studied under open conditions. There was considerable variability in diagnostic criteria, dosing parameters, and response rates between the various studies. Under controlled conditions, the aggregate literature shows that the stimulants had a clinically and statistically significant effect on reducing ADHD symptoms. Open studies on the nonserotonergic antidepressants (tricyclics, bupropion, and monoamine oxidase inhibitors) also show a moderate anti-ADHD effect. The literature appears to support the use of robust doses of both stimulants and antidepressants for ADHD in adults. Further controlled studies applying stringent diagnostic criteria and outcome methodology are necessary to define the range of pharmacotherapeutic options for adults with ADHD.

Attention deficit disorder in college students: facts, fallacies, and treatment

Attention deficit disorder (ADD), with or without hyperactivity, is a common but highly misunderstood and frequently underdiagnosed condition in college students. It affects students' academic and social success and emotional development. ADD is an invisible impairment of cortical regulation of activity and impulse control that is often hereditary, is as common in women as in men, and does not subside or disappear at puberty. ADD increases the risk of drug abuse, delinquency, incarceration, job failure, marital discord, and divorce. In college students, ADD is amenable to treatment in a multimodal program combining medication; individual, family, and group psychotherapy; career counseling; and cognitive control, together with electronic prostheses and special accommodations in the college classroom.

Drug treatment of the personality disorders

Many people with well defined borderline and schizotypal personality disorders may benefit considerably from small doses of neuroleptics. Depression that occurs with personality disorders, which is frequent, responds poorly to tricyclics but may respond better to neuroleptics, while the response to ECT is usually short lived. Selected borderline subjects may respond to MAOIs, particularly where there is a history of childhood hyperactivity. Carbamazepine and lithium may help some individuals with episodic behavioural dyscontrol and aggression, even in the absence of epileptic, affective or organic features. Drug treatments can be combined with psychotherapy, but further placebo-controlled trials are needed to clarify which drugs are most useful, and whether there are any useful clinical predictors of drug responsiveness.

GBR12909 antagonizes the ability of cocaine to elevate extracellular levels of dopamine

Rats were administered various IP doses of the high-affinity dopamine (DA) reuptake inhibitor 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-[3-phenylpropyl]piperazine (GBR12909). The caudate nuclei were removed 60 min after drug administration and stored at -70 degrees C. Striatal membranes were prepared later. The results demonstrated that GBR12909 produced a dose-dependent decrease in the binding of [3H]cocaine or [3H]GBR12935 to the DA transporter (ED50 about 10 mg/kg). Saturation binding studies with [3H]GBR12935 showed that this was due to both an increase in the Kd, due to residual drug, and to a decrease in the Bmax. At a dose of 25 mg/kg IP, GBR12909 produced a 50% decrease in the Bmax, and a 3.4-fold increase in the Kd. In the in vivo microdialysis studies, GBR12909 (25 mg/kg IP) produced a modest, long-lasting and stable elevation of extracellular DA. Administration of cocaine through the microdialysis probe to rats pretreated with either saline or GBR12909 (25 mg/kg IP) produced a dose-dependent increase in extracellular DA in both groups. GBR12909 inhibited cocaine-induced increases in extracellular DA by about 50% at all doses. These data collectively indicate that at a dose sufficient to decrease by 50% the Bmax of [3H]GBR12935 binding sites, GBR12909 antagonizes the ability of cocaine to elevate extracellular DA by 50%. Further studies will be needed to evaluate a possible role for GBR12909 in the medical treatment of cocaine addiction.