Original ArticlesDecreased platelet peripheral-type benzodiazepine receptors in adolescent inpatients with repeated suicide attempts
Introduction
Peripheral-type benzodiazepine receptors (PBR) play a role in cholesterol translocation from the outer to the inner mitochondrial membrane (Krueger and Papadopoulos 1990), which is the rate limiting step of steroidogenesis. Studies have shown that PBR are sensitive to hormonal changes and stress Drugan et al 1986, Ferrarese et al 1990, Burgin et al 1996, Drugan 1996; upregulation was demonstrated after exposure to acute stress, while downregulation is a consistent finding during chronic stressful conditions Drugan et al 1986, Drugan et al 1987, Drugan et al 1988, Novas et al 1987, Okun et al 1988, Karp et al 1989, Rago et al 1989a, Rago et al 1989b, Dar et al 1991, Rocca et al 1991, Weizman et al 1994, Johnson et al 1998. This bidirectional effect of stress on PBR expression may be important in the regulation of adrenal steroid biosynthesis Weizman and Gavish 1993, Weizman et al 1994, Burgin et al 1996. A decrease in PBR have also been demonstrated in several psychiatric disorders, such as generalized anxiety disorder (GAD) Weizman et al 1987, Ferrarese et al 1990, Rocca et al 1998, generalized social phobia (GSP) (Johnson et al, 1998), panic disorder (PD) (Marazziti et al 1994), and post-traumatic stress disorder (PTSD) (Gavish et al 1996), but not in obsessive-compulsive disorder (OCD) Weizman et al 1993, Weizman and Gavish 1993, Weizman et al 1996, Marazziti et al 1994, major depression (Weizman et al 1995), or attention-deficit hyperactivity disorder (ADHD) Weizman et al 1993, Weizman and Gavish 1993, Weizman et al 1993.
Adolescent suicide is a major public health problem (Spirito et al 1989) that is often associated with both acute and chronic stress (Rudd 1990). Research indicates that adolescents who have attempted suicide have high levels of life stress (Lewinsohn et al 1994), and that adolescents who have committed suicide were significantly more likely to have experienced stressful interpersonal conflicts, legal problems, and disruption of romantic attachments than community control subjects (Brent et al 1993). In view of these findings, we hypothesized that adolescents who have made repeated suicidal attempts may have decreased PBR density.
Section snippets
Subjects
Two groups of patients were compared: nine consecutively admitted inpatients aged 13–20 years with a history of at least three suicide attempts within the past year (suicidal group), and ten age-matched adolescent inpatients, hospitalized during the same period, who had no prior history of suicide attempts (control group). The suicidal behaviors were assessed by a senior child psychiatrist (AA) as part of the routine clinical intake process. The instrument used for this purpose was the Child
Results
The clinical data of the study groups are presented in Table 1, and results for the psychometric tests in Table 2. As expected, SRS scores were significantly higher (by 126%) in the suicidal group (p < .005). A significant difference (of 106%) was also found for the OAS (p < .05), but not for the other psychological measures.
Results of the receptor binding parameters are displayed in Table 3. A significant decrease in platelet PBR density (−35%) was observed in the suicidal group as compared to
Discussion
There are substantial limitations to this study which include a small number of patients and a failure to match the subjects’ diagnostically. Thus, although there are no significant differences between the groups on measures of depression and anxiety, the p values for the BDI (.09), STAI-T (.20), and STAI-S (.17) might have been significant if the sample size had been larger.
Nevertheless, the major finding of this study is that platelet PBR density is significantly decreased in suicidal
Acknowledgements
This study was supported by the Golden Gate Foundation (London) and the Sarah and Moshe Mayer Foundation for Research (Geneva and Tel Aviv)
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