博士 / 高雄醫學大學 / 醫學研究所博士班 / 105 / Craving is one of the key components of addiction and the driving forces behind continued use of addictive substances in spite of increasingly severe consequences. Recently studies showed that implicit attitude may relate to substance use and craving. Methadone maintenance therapy (MMT) has been shown to effectively reduce heroin use. How the effects of methadone on craving, implicit attitude and brain funtinal connectivity is still not exactly known. The present study contained four parts. The first part of the study aimed to examine the difference in implicit attitude toward heroin between heroin users and healthy controls. The results found that the difference in implicit craving between heroin users and health groups was significant, indicating that compared with the health controls, heroin users showed more favor unconscious craving when they faced to heroin-related stimulus.
The second part of the study aimed to examine the association of craving and implicit attitude with frequency of heroin use in heroin users with MMT. The results showed that craving and favorable implicit attitude were positively associated with the frequency of heroin use,as well as that craving was a risk factor for continuing heroin use.
The third part of the study aimed to examine the effects of craving and implicit attitude on severity of heroin dependence and methadone attendance rates in heroin users with MMT using the structured equation model (SEM). The results showed that craving was positively related to heroin dependence. Implicit attitude contributed to heroin dependence directly and indirectly through explicit craving. Craving was positively related to MMT adherence, whereas implicit had a indirect effect on MMT adherence.
The fourth part of the study aimed to examine abnormal resting state functional connectivity in heroin users under MMT using resting functional magnetic resonance imaging (fMRI). Resting fMRI experiments and urine heroin analysis were performed. The results showed that heroin users had a significantly lower interhemispheric insular functional connectivity. They also exhibited a lower functional connection between insula and contralateral inferior orbital frontal lobe. After controlling for age, educational level and methadone dosage, a higher interhemispheric insular functional connection was significantly associated with a lower risk of a positive urine heroin analysis result.
In conclusion, the first part of study showed heroin users have a favor implicit attitude against heroin. The second part of study showed that level of heroin use are associated with craving and implicit attitude against heroin. Only craving, not implicit attitude, can predict abstinence of heroin use. The third part of study indicated craving contributs to level of heroin dependence and attendance rate for methadone directly. Implicit attitude can contribute to the level of heroin dependence directly. Therefore, different cognitive processes toward heroin use may have different influences on heroin users’ drug-using behaviors. The results support that both implicit attitude and craving are of clinical importance in the treatment of heroin users. For the fourth part, abnormal interhemispheric functional connectivities between the insula and the amygdala, caudate, putamen, and the inferior orbital frontal lobe, developed in heroin users undergoing MMT. A less abnormal interhemispheric insula connection was associated with a lower risk of a positive urine analysis result. Our results provided insight into interhemispheric functional connections between the insula and other brain areas in heroin users under MMT.
| Identifer | oai:union.ndltd.org:TW/105KMC05534010 |
| Date | January 2017 |
| Creators | Pei-Wei Wang, 王鵬為 |
| Contributors | Cheng-Fanf Yen, Yi-Hsin Yang, 顏正芳, 楊奕馨 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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