Use of repetitive transcranial magnetic stimulation for treatment in psychiatry

Transcranial magnetic stimulation in the treatment of substance addiction

Transcranial magnetic stimulation (TMS) is a noninvasive method of brain stimulation used to treat a variety of neuropsychiatric disorders, but is still in the early stages of study as addiction treatment. We identified 19 human studies using repetitive TMS (rTMS) to manipulate drug craving or use, which exposed a total of 316 adults to active rTMS. Nine studies involved tobacco, six alcohol, three cocaine, and one methamphetamine. The majority of studies targeted high-frequency (5-20 Hz; expected to stimulate neuronal activity) rTMS pulses to the dorsolateral prefrontal cortex. Only five studies were controlled clinical trials: two of four nicotine trials found decreased cigarette smoking; the cocaine trial found decreased cocaine use. Many aspects of optimal treatment remain unknown, including rTMS parameters, duration of treatment, relationship to cue-induced craving, and concomitant treatment. The mechanisms of rTMS potential therapeutic action in treating addictions are poorly understood, but may involve increased dopamine and glutamate function in corticomesolimbic brain circuits and modulation of neural activity in brain circuits that mediate cognitive processes relevant to addiction, such as response inhibition, selective attention, and reactivity to drug-associated cues. rTMS treatment of addiction must be considered experimental at this time, but appears to have a promising future.

Los nuevos desarrollos tecnológicos aplicados al tratamiento psicológico

El desarrollo de nuevas tecnologías ha alcanzado prácticamente a todo el desarrollo humano. En el caso de la psicología clínica, ha significado nuevos avances en el conocimiento, evaluación y tratamientos psicológicos de diferentes problemas y trastornos. En este trabajo se revisan cuatro desarrollos que han tenido una expansión importante: el uso de internet para el tratamiento psicológico, el uso de la realidad virtual, el neurofeedback y la estimulación magnética transcraneal. Se presenta brevemente cada técnica o procedimiento, su aplicación a problemas concretos, sus ventajas y sus inconvenientes. Finalmente se discute el desarrollo de estos recursos y la necesidad de seguir aportando conocimientos que vayan mejorando su eficacia y su eficiencia, de acuerdo con tipos de pacientes, patologías, procedimiento específico, así como evitar efectos indeseables.

Induction of central nervous system plasticity by repetitive transcranial magnetic stimulation to promote sensorimotor recovery in incomplete spinal cord injury

Cortical and spinal cord plasticity may be induced with non-invasive transcranial magnetic stimulation to encourage long term potentiation or depression of neuronal circuits. Such plasticity inducing stimulation provides an attractive approach to promote changes in sensorimotor circuits that have been degraded by spinal cord injury (SCI). If residual corticospinal circuits can be conditioned appropriately there should be the possibility that the changes are accompanied by functional recovery. This article reviews the attempts that have been made to restore sensorimotor function and to obtain functional benefits from the application of repetitive transcranial magnetic stimulation (rTMS) of the cortex following incomplete spinal cord injury. The confounding issues that arise with the application of rTMS, specifically in SCI, are enumerated. Finally, consideration is given to the potential for rTMS to be used in the restoration of bladder and bowel sphincter function and consequent functional recovery of the guarding reflex.

Obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a common heterogeneous psychiatric disorder manifesting with obsessions and compulsions. Obsessions are intrusive, recurrent, and persistent unwanted thoughts. Compulsions are repetitive behaviors or mental acts that an individual feels driven to perform in response to the obsessions. The heterogeneity of OCD includes themes of obsessions, types of rituals, presence or absence of tics, etiology, genetics, and response to pharmacotherapy. Complications of OCD include interpersonal difficulties, unemployment, substance abuse, criminal justice issues, and physical injuries. Areas of the brain involved in the pathophysiology include the orbitofrontal cortex, anterior cingulate gyrus, and basal ganglia. Overall, OCD may be due to a malfunction in the cortico-striato-thalamo-cortical circuit in the brain. Neurotransmitters implicated in OCD include serotonin, dopamine, and glutamate. Numerous drugs such as atypical antipsychotics and dopaminergic agents can cause or exacerbate OCD symptoms. The etiology includes genetics and neurological insults. Treatment of OCD includes psychotherapy, pharmacotherapy, electroconvulsive therapy, transcranial magnetic simulation, and in extreme cases surgery. Exposure and response prevention is the most effective form of psychotherapy. Selective serotonin reuptake inhibitors (SSRIs) are the preferred pharmacotherapy. Higher doses than listed in the package insert and a longer trial are often needed for SSRIs than compared to other psychiatric disorders. Alternatives to SSRIs include clomipramine and serotonin/norepinephrine reuptake inhibitors. Treatment of resistant cases includes augmentation with atypical antipsychotics, pindolol, buspirone, and glutamate-blocking agents.

Delayed mood transitions in major depressive disorder

The hypothesis defended here is that the process of mood-normalizing transitions fails in a significant proportion of patients suffering from major depressive disorder. Such a failure is largely unrelated to the psychological content. Evidence for the hypothesis is provided by the highly variable and unpredictable time-courses of the depressive episodes. The main supporting observations are: (1) mood transitions within minutes or days have been reported during deep brain stimulation, naps after sleep deprivation and bipolar mood disorders; (2) sleep deprivation, electroconvulsive treatment and experimental drugs (e.g., ketamine) may facilitate mood transitions in major depressive disorder within hours or a few days; (3) epidemiological and clinical studies show that the time-to-recovery from major depressive disorder can be described with decay models implying very short depressive episodes; (4) lack of relationship between the length of depression and recovery episodes in recurrent depression; (5) mood fluctuations predict later therapeutic success in major depressive disorder. We discuss some recent models aimed to describe random mood transitions. The observations together suggest that the mood transitions have a wide variety of apparently unrelated causes. We suggest that the mechanism of mood transition is compromised in major depressive disorder, which has to be recognized in diagnostic systems.

Neurocognitive Basis of Schizophrenia: Information Processing Abnormalities and Clues for Treatment

Schizophrenia is a chronic and severe psychiatric disorder that affects all aspects of patients’ lives. Over the past decades, research applying methods from psychology and neuroscience has increasingly been zooming in on specific information processing abnormalities in schizophrenia. Impaired activation of and connectivity between frontotemporal, frontoparietal, and frontostriatal brain networks subserving cognitive functioning and integration of cognition and emotion has been consistently reported. Major issues in schizophrenia research concern the cognitive and neural basis of hallucinations, abnormalities in cognitive-emotional processing, social cognition (including theory of mind), poor awareness of illness, and apathy. Recent findings from cognitive neuroscience studies in these areas are discussed. The findings may have implications for treatment, for example, noninvasive neurostimulation of specific brain areas. Ultimately, a better understanding of the cognitive neuroscience of schizophrenia will pave the way for the development of effective treatment strategies.