Repetitive behavior

Serotonin involvement. There is substantial evidence supporting abnormal 5-HT function in autism, particularly with regard to both the social deficit and repetitive behavior dimensions of this disorder. Many studies of the neurobiology of autism have focused on 5-HT, which is implicated in the regulation of many functions relevant to autism, such as learning, memory. 

Studies with the 5-HTu agonist sumatriptan demonstrated that altered neuroendocrine response reflecting 5-HTid sensistivity significantly correlates with severity of the repetitive behavior domain (Hollander et al., 2000). In addition, there is evidence for improvement in global severity as well as improvements in both social deficits and decreased repetitive behavior in autistic individuals with serotonin reuptake inhibitor (SRI) treatment (Gordon et al., 1993, McDougle et al., 1996, Hollander et al, 1998). There is substantial evi-... 

Hollander, E., Novotny, S., Allen, A., Aronowitz, B., and DeCaria, C. (2000) The relationship between repetitive behaviors and growth hormone response to sumatriptan challenge in adult autistic disorders. Neuropsychopharmacology 22 163-167. 

The selective serotonin reuptake inhibitors (SSRI) have been used in adults for a wide variety of disorders, including major depression, social anxiety (social phobia), generalized anxiety disorder (GAD), eating disorders, premenstrual dysphoric disorder (PMDD), post-traumatic stress disorder (PTSD), panic, obsessive-compulsive disorder (OCD), trichotillomania, and migraine headaches. Some of the specific SSRI agents have an approved indication in adults for some of these disorders, as reviewed later in this chapter. The SSRIs have also been tried in children and in adults for symptomatic treatment of pain syndromes, aggressive or irritable ( short fuse ) behavior, and for self-injurious and repetitive behaviors. This chapter will review general aspects of the SSRIs and discuss their approved indications in children and adolescents. 

The ritualistic, repetitive behaviors in autism are often seen as parallel to some of the behaviors seen in OCD spectrum disorders. Because of this, CMI was initially compared with both DMI and placebo in the treatment of children with autism. Clomipramine showed superior efficacy to both DMI and to placebo (Gordon et... 

An open trial of valproic acid in 18 MR patients (8-18 years of age) with irritability and self-injury showed that 12 of 18 (67%) improved (Kastner et al., 1993). Finally, valproic acid was studied in a 10-month retrospective design in FDD spectrum-disordered patients with mood lability, impulsivity, and aggression. Ten of 14 (71%) patients responded to the agent with a decrease in mood lability, impulsivity, aggression, and repetitive behaviors and improvement in social relatedness and language (Hollander et al., 2000). 

Although many schizophrenic patients demonstrate obsessive-compulsive symptoms, this problem has received little systematic investigation. There are conflicting case reports of patients with obsessive-compulsive symptoms who failed to benefit when given an antiobsessional drug in addition to an antipsychotic, and other cases in which this strategy was beneficial (176). There are also reports of certain repetitive behaviors that mimic OCD that are benefited by the addition of clomipramine (177,178 and 179). Schulz has proposed the term schizo-obsessive to describe this clinical presentation ( 180). 

Pulman J, Yassa R, Ananth J. Clomipramine treatment of repetitive behavior. Can J Psychiatry 1984 29 254-255. 

OCD is known to respond to serotonergic antidepressants. It is characterized by repetitive anxiety-provoking thoughts (obsessions) or repetitive behaviors aimed at reducing anxiety (compulsions). Clomipramine and several of the SSRIs are approved for the treatment of OCD, and they are moderately effective. Behavior therapy is usually combined with the antidepressant for additional benefits. 

Many users prefer meth to cocaine because, while its effects are similar, they are longer lasting and can be maintained for days at a time. However, after prolonged use, users often suffer from paranoia, hallucinations, and weird repetitive behavior. 

Furusho J, Matsuzaki K, Ichihashi I, Satoh H, Yamaguchi K, Kumagai K (2001) Alleviation of sleep disturbance and repetitive behavior by a selective serotonin re-uptake inhibitor in a boy with Asperger s syndrome. Brain Dev 23 135-137... 

Since equilibrium is a stable state, reaction systems at, or close to, equilibrium will not oscillate27. Therefore, one necessary condition for oscillation is that the system be far from equilibrium. We are, of necessity, dealing with open, irreversible systems. Second, and equally important, is the existence of a feedback mechanism. Oscillation or periodicity implies a return to some initial state. That this repetitive behavior would imply a particular kind of feedback, however, is not at all obvious. 

Several other behavioral abnormalities have also been described in 5-HT2C-R KOs. These mice display several types of repetitive behavior that have been likened to compulsions (110). 5-HT2C-R KO mice also display altered stress responses (111), a deficit in maternal behavior (Storm, unpublished data), decreased spatial memory performance in the Morris water maze, and decreased long-term potentiation (LTP) in medial perforant path-dentate gyrus synapses (112). 

Getting hung up is a manifestation of stimulant-induced compulsive behavior that includes overfocusing and stereotypical or repetitive behavior. Consistent with the brain-disabling principles, Kramer et al. (1970) identified these abnormal compulsive behavioral reactions as the sought-after effect in children and adults ... 

Selective serotonin reuptake inhibitors (SSRIs) inhibit the neuronal reuptake of serotonin in the central nervous system and have shown mixed efficacy in the treatment of autistic symptoms (Moore et al., 2004). A number of studies have shown reductions in repetitive behaviors, lethargy, inappropriate speech, and improvements in the ability to relate to others, cognition, language improvement with fluoxetine (DeLong et al., 1998 Fatemi et al., 1998 Peral et al., 1999), fluvoxamine (McDougle et al., 1996b), and sertraline (Steingard et al., 1997). However, other studies have shown a lack of response with fluvoxamine (Martin et al., 2003) and citalopram (Couturier and Nicolson, 2002). 

Plasma oxytocin has been shown to be reduced in autistic children and moreover, levels of oxytocin were correlated with social impairment (Modahl et al., 1998). A follow-up study using the same subjects found that the autistic children had higher levels of the precursor of oxytocin when compared with controls, suggesting that reduced plasma oxytocin in autistic children may be related to how oxytocin is processed (Green et al., 2001). Preliminary studies have demonstrated that infusion with oxytocin can reduce repetitive behaviors such as... 

Toxicity primarily involves the CNS and cardiovascular system. CNS effects include increased alertness, restlessness, decreased appetite, irritability, stereotyped repetitive behavior, and insomnia with low doses. With larger exposures confusion, panic reactions, aggressive behavior, hallucinations, seizures, delirium, coma, and death can occur. Intracranial bleeding can result from untreated hypertension. Trauma is common secondary to the changes in behavior and decreased judgment. Frequent use results in fatigue, paranoia, and depression. Cardiovascular effects include increased heart rate and blood pressure, chest pain, myocardial ischemia or... 

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