In our study, we found that most of participants used pregabalin in a continuous course (86.7%). This may be due to its cheap price and its euphoric effect. Also, our results revealed that 79.5% of the patients abused pregabalin with other substances. Close to our results, Lancia et al. who found that pregabalin was frequently combined with other substances mostly opiates . This result agree with Al-Husseini et al. 2017 who reported that pregabalin abuse is common among cigarette smokers and poly-drug users . This can be explained some pregabalin abusers mix it with other drugs like tramadol and synthetic cannabinoid to potentiate its effect .
In our study, we found that our participants took other substances, 67.4% of them received tramadol, heroin 66.3%, cannabis 65.1%, other drugs (most frequent was conventin) 44.6%, and benzodiazepines 27.7%. Screening urine test was positive in 62.7% of participants most frequently was heroin 41% and cannabis 34.9%. In line with our results, numerous studies found that pregabalin was frequently combined with other drugs but mostly opiates [21, 22]. In contrast to our result Gabr found that heroin was not commonly abused with pregabalin 6.5% , and these differences may be due to different targeted population.
According to Beck Suicidal Ideation Scale, our finding showed that 67.6%of participants had no suicidal ideations but 19.3% of them had low risk of suicide and 13.3 had high risk of suicide so total participants who had suicidal ideation were 32.6%. Close to our result, Hashish and Awad found that suicidal ideation in pregabalin abuse group was 39.2% . Pregabalin decreases the serotonin level and this may be responsible for suicidal ideation and self-harm . Acute and chronic drug abuse may impair judgment, decline impulse control, and interrupt neurotransmitter pathways, leading to suicidal tendencies through disinhibition .
Our result revealed that there was statistical significant increase in risk of suicide among patients who were continuously abusing pregabalin and who had positive pregabalin urine test. In line with our result, Tandon et al. reported a case of pregabalin-induced suicidal ideation and behaviors after continuous use of pregabalin. The probable mechanism explained for the self-harm behavior is the reduction of serotonin by pregabalin .
In our study, there was significant positive correlation between Beck suicidal ideation score and duration of pregabalin abuse, maximum and daily dose. In line with this result, Andersohn et al. (2010) present a case of dose-dependent pregabalin-induced suicidal ideations. They found that increasing the treatment with pregabalin at a dosage of 600 mg lead to suicidal ideation experienced by the patient. After reducing the dosage to 300 mg/day, the suicidal thoughts disappeared completely. They propose a dose-dependent effect of pregabalin to induce suicidal ideation. They report that pregabalin may have a potential for inducing suicidal ideations, which was a dose-dependent effect in their case . Another study confirmed our result, revealed that after the beginning of pregabalin, the patients reported changes in mood, and development of depression and/or suicidal ideation, which improved with decreasing the dose of pregabalin . Our results revealed that there was significant positive relation between suicidal ideation and tramadol addiction and there was a positive statistical significant correlation between beck suicidal ideation score and both the dose and the duration of tramadol abuse. In line with our result, Artenie et al. (2014) revealed that the main risk factor for suicide attempt among addict was increase duration of substance use . Another study confirmed our result, revealed that the duration of tramadol use could be considered a strong risk factor for suicide, as increasing the duration of tramadol results in increasing suicide risk . The effects of comorbid psychiatric disorders including major depression disorder, generalized anxiety disorder borderline personality disorder and antisocial personality disorder were studied in another paper under revision of Middle east Current Psychiatry Journal .
Limitations of the study
1. With increased number of our sample size, the association between suicide and pregabalin abuse will be more obvious.
2. We did not assess the bidirectional link between pregabalin abuse and suicide; so, longitudinal studies are recommended to clarify the relation and causality between pregabalin abuse and suicide.
3. Most of our subjects were abusing other substances with pregabalin; future studies with monosubstance abuse of pregabalin were recommended to clarify with more certainty the relation between pregabalin and suicide.
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