Lamotrigine Augmentation in Treatment-Resistant Pediatric Obsessive-Compulsive Disorder with a 16 Month Follow-up

Pharmacotherapeutic Strategies and New Targets in OCD

Effective pharmacological and psychotherapeutic treatments are well established for obsessive-compulsive disorder (OCD). Serotonin reuptake inhibitors (SRIs) are first-line treatment and are of benefit to about half of patients. Augmentation of SRI treatment with low-dose neuroleptics is an evidence-based second-line strategy. Specialty psychotherapy is also used as both first-line and second-line treatment and can benefit many. However, a substantial number of patients do not respond to these treatments. New alternatives are urgently needed. This review summarizes evidence for these established pharmacotherapeutic strategies, and for others that have been investigated in refractory disease but are not supported by the same level of evidence. We focus on three neurotransmitter systems in the brain: serotonin, dopamine, and glutamate. We summarize evidence from genetic, neuroimaging, animal model, and other lines of investigation that probe these three systems in patients with OCD. We also review recent work on predictors of response to current treatments. While many studies suggest abnormalities that may provide insight into the pathophysiology of the disorder, most studies have been small, and non-replication of reported findings has been common. Nevertheless, the gradual accrual of evidence for neurotransmitter dysregulation may in time lead the way to new pharmacological strategies.

Lamotrigine Uses in Psychiatric Practice

BACKGROUND

Lamotrigine (LAM), an antiepileptic, with panoply of indications and uses in neurology, is FDA approved, in psychiatry, for bipolar prophylaxis. Apart from this indication, trend of its use in psychiatry is on the rise addressing a multitude of disorders.

STUDY QUESTION

LAM remains one of only few psychotropic drugs with antiglutamate activity. This might render LAM a potential therapeutic option in treatment-resistant major psychiatric disorders. We reviewed LAM pharmacology and its diverse indications while examining the extant evidence.

METHODS

EMBASE, Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane Database of Systemic Reviews were searched for all relevant studies up to date of June 2016.

RESULTS

Sound evidence supports use of LAM for acute bipolar depression and prophylaxis, treatment-resistant schizophrenia, treatment-resistant obsessive-compulsive disorder, posttraumatic stress disorder, depersonalization disorder, and affective dysregulation and behavioral dyscontrol domains of borderline personality disorder. Less compelling evidence is present for use in behavioral and psychological symptoms of dementia and neuropsychiatric sequelae of traumatic brain injury. No evidence supports use in autism spectrum disorder or acute unipolar depression.

CONCLUSIONS

LAM is an important addition to the psychopharmacological armamentarium. Level of evidence supporting the use of LAM in off-label indications is highly variable, and hence, sound clinical judgment is necessary for its proper use and placement in real-life psychiatric practice and psychopharmacotherapy algorithms.

Glutamate-Modulating Drugs as a Potential Therapeutic Strategy in Obsessive-Compulsive Disorder

OBJECTIVE

Obsessive-compulsive disorder (OCD) is a mental disease commonly associated with severe distress and impairment of social functioning. Serotonin reuptake inhibitors and/or cognitive behavioural therapy are the therapy of choice, however up to 40% of patients do not respond to treatment. Glutamatergic signalling has also been implicated in OCD. The aim of the current study was to review the clinical evidence for therapeutic utility of glutamate-modulating drugs as an augmentation or monotherapy in OCD patients.

METHODS

We conducted a search of the MEDLINE database for clinical studies evaluating the effect of glutamate-modulating drugs in OCD.

RESULTS

Memantine is the compound most consistently showing a positive effect as an augmentation therapy in OCD. Anti-convulsant drugs (lamotrigine, topiramate) and riluzole may also provide therapeutic benefit to some OCD patients. Finally, ketamine may be of interest due to its potential for a rapid onset of action.

CONCLUSION

Further randomized placebo-controlled trials in larger study populations are necessary in order to draw definitive conclusions on the utility of glutamate-modulating drugs in OCD. Furthermore, genetic and epigenetic factors, clinical symptoms and subtypes predicting treatment response to glutamate-modulating drugs need to be investigated systematically.