Charles Cartwright

A randomized double-blind fluvoxamine/placebo crossover trial in pathologic gambling

BACKGROUND The study assessed the efficacy and tolerability of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine in the treatment of pathologic gambling (PG). METHODS A 16-week randomized double-blind crossover design insured that each subject received 8 weeks of fluvoxamine and 8 weeks of a placebo. Fifteen patients entered and 10 subjects, all male, completed the study. RESULTS Fluvoxamine resulted in a significantly greater percent improvement in overall gambling severity on the PG Clinical Global Impression (PG-CGI) scale. There was a significant drug effect on gambling urge and behavior as measured by the PG modification of the Yale-Brown Obsessive Compulsive Scale and PG-CGI scale improvement scores; however, there was a significant interaction of drug effect with the order of administration of drug and placebo. Post hoc analysis, treating each phase as a separate trial, demonstrated a significant difference between fluvoxamine and the placebo in the second phase of the trial but not in the first. Fluvoxamine side effects were of only mild intensity and consistent with SSRI treatment and were not associated with early withdrawal from the study. CONCLUSIONS These findings suggest that fluvoxamine is well tolerated and may be effective in the treatment of PG in an acute trial, and that an early placebo effect in PG treatment appears to diminish over time. To confirm this finding and to determine whether improvement persists over an extended period of time, a longer duration parallel-design trial with long-term maintenance follow-up should be conducted in a larger and more diverse PG population.

Effect of fluoxetine on regional cerebral metabolism in autistic spectrum disorders: a pilot study

The regional metabolic effects of fluoxetine were examined in patients with autism spectrum disorders. Six adult patients with DSM-IV and Autism Diagnostic Interview (ADI) diagnoses of autism (n = 5) and Aspergers syndrome (n = 1), entered a 16-wk placebo-controlled cross-over trial of fluoxetine. The patients received (18)F-deoxyglucose positron emission tomography with co-registered magnetic resonance imaging at baseline and at the end of the period of fluoxetine administration. After treatment, the patients showed significant improvement on the scores of the Yale--Brown Obsessive--Compulsive Scale -- Obsessions subscale and the Hamilton Anxiety Scale; Clinical Global Impressions -- Autism scores showed 3 of the patients much improved and 3 unchanged. Relative metabolic rates were significantly higher in the right frontal lobe following fluoxetine, especially in the anterior cingulate gyrus and the orbitofrontal cortex. Patients with higher metabolic rates in the medial frontal region and anterior cingulate when unmedicated were more likely to respond favourably to fluoxetine. These results are consistent with those in depression indicating that higher cingulate gyrus metabolic rates at baseline predict SRI response.

Venlafaxine in Children, Adolescents, and Young Adults With Autism Spectrum Disorders: An Open Retrospective Clinical Report

Autism is characterized by social deficits, communication and language impairments, narrow restricted interests, repetitive behaviors, inattention, and hyperactivity. While selective serotonin reuptake inhibitors have demonstrated efficacy in treating core symptoms of autism, norepinephrine reuptake inhibitors have demonstrated efficacy in symptoms of attention-deficit hyperactivity disorder (ADHD). An open, retrospective clinical study with venlafaxine evaluated its effect on core symptoms of autism as well as associated features of ADHD. Ten consecutive subjects meeting Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), criteria for an autism spectrum disorder were treated with venlafaxine, initiated at 12.5 mg per day and adjusted on a flexible basis. Six of 10 completers were judged to be sustained treatment responders, by scoring 1 (very much improved) or 2 (much improved) on the Clinical Global Impressions improvement scale. Venlafaxine was effective in low dosages (mean, 24.37 mg/day; range, 6.25 to 50 mg/day) and was well tolerated. Improvement was noted in repetitive behaviors and restricted interests, social deficits, communication and language function, inattention, and hyperactivity. Controlled treatment trials with venlafaxine are warranted in autism spectrum disorders. (J Child Neurol 2000;15:132-135).

The relationship between repetitive behaviors and growth hormone response to sumatriptan challenge in adult autistic disorder

Autism is heterogeneous with respect to clinical symptoms and etiology. To sort out this heterogeneity in autism, we investigated whether specific neurobiological markers vary in parallel to core symptomatology. Specifically, we assessed growth hormone response to the 5-HT 1d agonist, sumatriptan, and linked this measure of serotonergic function to the severity of repetitive behaviors in adult autistic patients. Eleven adult patients with autism or Aspergers disorder were randomized to single dose sumatriptan (6 mg SQ) and placebo challenges, separated by a one-week interval. In adult autistic disorders, severity of repetitive behaviors at baseline, as measured by YBOCS-compulsion score, significantly positively correlated with both peak delta growth hormone response and area under the curve growth hormone response to sumatriptan. Thus, the severity of a specific behavioral dimension in autism (repetitive behaviors) parallels the sensitivity of the 5-HT 1d receptor, as manifest by sumatriptan elicited GH response.

Regional Glucose Metabolism within Cortical Brodmann Areas in Healthy Individuals and Autistic Patients

A new Brodmann area (BA) delineation approach was applied to FDG-PET scans of autistic patients and healthy volunteers (n = 17 in each group) to examine relative glucose metabolism (rGMR) during performance of a verbal memory task. In the frontal lobe, patients had lower rGMR in medial/cingulate regions (BA 32, 24, 25) but not in lateral regions (BA 8–10) compared with healthy controls. Patients had higher rGMR in occipital (BA 19) and parietal regions (BA 39) compared with controls, but there were no group differences in temporal lobe regions. Among controls, better recall and use of the semantic-clustering strategy was associated with greater lateral and medial frontal rGMR, while decreased rGMR in medial-frontal regions was associated with greater perseverative/intrusion errors. Patients failed to show these patterns. Autism patients have dysfunction in some but not all of the key brain regions subserving verbal memory performance, and other regions may be recruited for task performance.

A Dimensional Approach to the Autism Spectrum

Autism is heterogeneous with respect to clinical symptoms and etiology. A significant limitation in research of the neurobiology and treatment of autism has been the lack of attention to this heterogeneity. A dimensional approach to the study of autism is valuable in linking key symptoms to the neurobiology and treatment of the disorder in a clinically meaningful way. In this article, we outline a dimensional approach to the autism spectrum, discuss the three core dimensions of autism and their neurobiology, and review the possible links of serotonin, anterior cingulate gyrus activity, and the immune marker D8/17 to the repetitive behavior/compulsivity dimensions.

SSRIs in the treatment of obsessive-compulsive disorder.

The introduction of the SSRIs (selective serotonin reuptake inhibitors) over the past decade has provided exciting new opportunities for the treatment of obsessive‐compulsive disorder (OCD). The serotonin hypothesis, based on the preferential response of OCD to the serotonin reuptake inhibitor, clomipramine, paved the way for research into the efficacy of the SSRIs in the treatment of this disorder. Large, controlled, multicenter studies have found clomipramine and the SSRIs, fluoxetine, fluvoxamine, sertraline, and paroxetine, to be effective and safe in the treatment of OCD. Meta‐analytic studies have reported that clomipramine is superior to the SSRIs; however, direct head‐to‐head comparisons suggest equal efficacy. As SSRIs have a more favorable side‐effect profile they may be preferable as first‐line treatment of OCD. Improvement following adequate OCD drug treatment is frequently partial whereupon augmentation strategies may become necessary. High rates of relapse have been reported on discontinuation of SRI treatment. Long‐term maintenance treatment has been found to be effective in sustaining initial therapeutic gains and bringing about further improvement. Depression and Anxiety, Volume 8, Supplement 1:105–113, 1998.

Increased growth hormone response to sumatriptan challenge in adult autistic disorders

Serotonergic (5-HT) abnormalities have been documented in autism. To assess sensitivity of the 5-HT1d receptor, growth hormone response to the 5-HT1d receptor agonist sumatriptan was studied in adult autistic patients and matched normal controls. In this study, 11 adult patients with autism or Aspergers disorder were compared with nine matched controls. All subjects were randomized to single dose sumatriptan (6 mg SQ) and placebo challenges, separated by a 1-week interval, and growth hormone was measured before and during the challenges. The results showed a highly significant diagnosisxdrugxtime interaction on repeated measure analysis covaried for baseline. This suggests that autistic patients had significantly greater growth hormone response to sumatriptan than normal controls, independent of placebo effects. Therefore, abnormalities in 5-HT regulation in autism may be related to increased sensitivity of the 5-HT1d inhibitory receptor in autism.

PHARMACOTHERAPY FOR OBSESSIVE-COMPULSIVE DISORDER

SSRIs and the tricyclic antidepressant clomipramine are the first-line therapies for patients with OCD, with the side-effect profile of SSRIs being more favorable than that of clomipramine. As many as 40% to 60% of patients with OCD may not respond to adequate trials of SRIs. Not all patients tolerate SSRIs, and delays in full therapeutic responses often occur. Thus, other pharmacologic approaches to treating patients with OCD have been investigated. Augmentation and monotherapy have been explored with serotonergic enhancers, dopamine and 5-HT antagonists, enhancers of second-messenger systems, and GABAergic agents with varying efficacy.