Assessment of frontal lobe functions in a sample of male cannabis users currently in abstinence: correlations with duration of use and their functional outcomes.

BACKGROUND: Previous research literature reported different results regarding the long-term effects that cannabis use can exert on the frontal lobe neurocognitive functions of its users. Another body of research suggested that cannabis use negatively affects the person's general level of occupational and psychosocial functioning consequently to these alterations. Some other research results did not support these findings. To date, it is still debatable whether chronic cannabis use triggers negative neurocognitive effects in chronic users even after a period of abstinence. Research data exploring consequent adverse outcomes on the general individual occupational and psychosocial functioning is not yet conclusive. RESULTS: We conducted this study to examine the residual neurocognitive effects of cannabis use, whether it is affected by duration of cannabis use before abstinence, and its relation to individual's global assessment of functioning exhibited in the person's occupational and social life whether it's family or friends. Our sample comprised 80 male participants (18-45 years old) who were grouped into 4 groups (3 groups with different durations of use and a control group), with no significant difference between the four studied groups regarding age, education, and socioeconomic level. The Kruskal Wallis test was used to test the significance of differences in the distribution of total frontal lobe battery results and the general assessment of function scores using GAF scores between study groups. Post hoc testing was performed to adjust for multiple comparisons using Bonferroni method. CONCLUSION: Data analysis showed that cannabis users experienced general functional disturbances that encompass impairments in social and occupational life aspects. These impairments in function are correlated with the presence of neurocognitive deficits even after a period of abstinence. Both having significant positive correlation with longer duration of cannabis use.

Spinal magnetic stimulation to treat chronic back pain: a feasibility study in veterans.

Aim: Chronic low back pain represents a significant societal problem leading to increased healthcare costs and quality of life. This study was designed to evaluate the feasibility and effectiveness of non-invasive spinal electromagnetic simulation (SEMS) to treat nonspecific chronic low back pain (CLBP). Methods: A single-site prospective study was conducted to evaluate SEMS in reducing pain and improving disability. A total of 17 patients received SEMS two to three sessions a week. The Numeric Rating Scale and the Modified Oswestry Disability Questionnaire were used to assess pain and disability. Results: Participants receiving SEMS exhibited statistically significant reductions in pain and disability. Conclusion: Current results suggest that non-invasive SEMS can be an effective treatment in reducing pain and improving disability associated with CLBP.

Buprenorphine, a partial opioid agonist, prevents modulation of H-reflex induced by pulsed electromagnetic stimulation in spinal cord injured rats.

Our recent study revealed that spinal electromagnetic stimulation (sEMS) applied at low (0.2 Hz) frequencies may improve diminished transmission in damaged spinal cord in spinal cord injured (SCI) rats. We have recently begun a pilot study investigating the effects of sEMS in non-injured and SCI humans. One unexpected result was the reduction of chronic low back pain (CLBP), reported by some patients following sEMS treatment. Chronic low back pain is one of the main causes of disability affecting the general population. Opioids are the most common drugs prescribed to US adults with CLBP. To optimize parameters for sEMS for pain treatment, in this study we used the SCI animal model and examined effects of sEMS applied at lumbosacral level on parameters and frequency-dependent depression (FDD) of Hoffmann H-reflex responses, known as common neurophysiological measures for evaluation of sensorimotor condition and plasticity in humans. We have also examined the interactive effects of sEMS and the opiate partial agonist Buprenorphine on the parameters of H-reflex in naïve and SCI rats. Consistent with previous reports, chronic SCI resulted in a marked decrease of threshold intensity required to evoke H-reflex and a lesser rate of FDD of the H-response in adult rats. Our current study revealed the optimum parameters of spinal EMS for best recovery of the properties of the H-reflex in chronic SCI animals. Here we demonstrate that electro-magnetic stimulation applied at spinal L4-L5 level with a pulsed mode (pulse at 20 Hz frequency for 5 sec with 25 sec break between pulses, total 40 trains for 20 min; PSEMS) reversed effects of SCI on key parameters of H-reflex: i.e. (1) restored the threshold intensity of electric current applied at tibial nerve to evoke the H-reflex and (2) recovered FDD properties of the H-reflex in SCI rats. Importantly, subcutaneous injections of Buprenorphine, prior to PSEMS administration, abolished the ability of PSEMS to recover both threshold intensity and FDD of the H-reflex in chronic SCI animals. These results suggest that a semi-synthetic opioid Buprenorphine and PSEMS might share common sites of action. We thus conclude that PSEMS might carry potential as a non-invasive treatment approach for chronic low back pain.

Modulation of H-reflex responses and frequency-dependent depression by repetitive spinal electromagnetic stimulation: From rats to humans and back to chronic spinal cord injured rats.

The lack of propagation of signals through survived fibers is among the major reasons for functional loss after incomplete spinal cord injury (SCI). Our recent results of animal studies demonstrate that spinal electromagnetic stimulation (SEMS) can enhance transmission in damaged spinal cord, and this type of modulation depends on the function of NMDA receptors at the neuronal networks below the injury level. Here, our pilot human study revealed that administration of repetitive SEMS induced long-lasting modulation of H-responses in both healthy and participants with chronic SCI. In order to understand the mechanisms underlying these effects, we have used an animal model and examined effects of SEMS on H-responses. Effects of SEMS on H-responses, frequency-dependent depression (FDD) of H-reflex, and possible underlying mechanisms have been examined in both naïve and rats with SCI. Our results demonstrate that consistent with the effects of SEMS on H-reflex seen in humans, repetitive SEMS induced similar modulation in excitability of peripheral nerve responses in both non-injured and rats with SCI. Importantly, our results confirmed the reduced FDD of H-reflex in SCI animals and revealed that SEMS was able to recover FDD in rats with chronic SCI. Using intraspinal injections of the NMDA receptor blocker MK-801, we have identified NMDA receptors as an important contributor to these SEMS-induced effects in rats with SCI. These results identify SEMS as a novel non-invasive technique for modulation of neuro-muscular circuits and, importantly, modulation of spinal networks after chronic SCI.

Dual Diagnosis and Suicide Probability in Poly-Drug Users.

OBJECTIVE: To determine the frequency of suicidal thoughts and suicidal probability among poly-substance abusers in Saudi population, and to examine the relation between dual diagnosis and suicidal thoughts. STUDY DESIGN: Case control study. PLACE AND DURATION OF STUDY: Al-Baha Psychiatric Hospital, Saudi Arabia, from May 2011 to June 2012. METHODOLOGY: Participants were 239 subjects, aged 18 - 45 years. We reviewed 122 individuals who fulfilled the DSM-IV-TR criteria of substance abuse for two or more substances, and their data were compared with that collected from 117 control persons. RESULTS: Suicidal cases were highly present among poly-substance abusers 64.75%. Amphetamine and cannabis were the most abused substances, (87.7% and 70.49%, respectively). Astatistically significant association with suicidality was found with longer duration of substance abuse (p < 0.001), using alcohol (p=0.001), amphetamine (p=0.007), volatile substances (p=0.034), presence of comorbid psychiatric disorders (dual diagnosis) as substance induced mood disorder (p=0.001), schizo-affective disorder (p=0.017), major depressive disorders (p=0.001), antisocial (p=0.016) and borderline (p=0.005) personality disorder. Suicidal cases showed significant higher scores (p < 0.001) of suicide probability scale and higher scores in Beck depressive inventory (p < 0.001). CONCLUSION: Abusing certain substances for long duration, in addition to comorbid psychiatric disorders especially with disturbed-mood element, may trigger suicidal thoughts in poly-substance abusers. Depression and suicide probability is common consequences of substance abuse.