The main findings of this study can be summarized as follows: 1) The majority of instances of SRB occurred in the age-group between 18 and 44. 2) Two-thirds of the reported cases were women. 3) Antidepressants, peripheral analgesics and neuroleptics were the main substances used for self-intoxication. 4) Most often, the substances came from the patient's own medication. 5) Although addiction played a relevant role, the majority of cases had no reported addiction disease. The most commonly abused substance was ethanol. 6) Factors associated with recurrent instances of SRB were: i) an underlying PD; ii) addiction problems; iii) the ingestion of antidepressants or neuroleptics.
Two thirds of the analyzed cases were female, and the proportion was particularly high among the < 18-year olds, which is in line with data from other studies (10, 12, 16, 20, 21, 29, 33). Spiller et al. showed that females constituted nearly 71% of all cases of self-intoxication in patients younger than 25 years (6). The high proportion of females may surprise, as the majority of completed suicides is performed by males (13–15). However, both our study and the study conducted by Spiller et al. focus on self-intoxication, which is the preferred method for females when displaying SRB (18, 19). Furthermore, the present study shows, that most cases of self-intoxication are performed in the age group between 18 and 44 years, which is in accordance with further studies on this subject (17).
Antidepressants constitute the most commonly used substance group followed by peripheral analgesics. The latter were predominantly used by younger individuals, which is also reflected in the existing literature (6, 25, 26). In contrast to many other studies, in which benzodiazepines are usually ranked among the three most popular substances (7, 17, 22, 28–30, 33), they ranged only on fourth place in our investigation. A similar pattern could be detected regarding paracetamol, which ranged as the most common single substance in international studies (28, 31 and also Table 4), but was only the fourth common in our study. Instead, ibuprofen was the most common single substance, which is important as ibuprofen has a high mortality rate (in large overdoses) despite its perceived harmlessness (27, 32). As the study at hand presents a profile of the characteristics of individuals displaying SRB through self-intoxication in Germany, the relatively uncommon use of benzodiazepines and paracetamol might reflect a more geographic preference or could indicate a change in prescription behavior.
Almost 80% of the cases had a prevalence of PD, which is higher compared to data found in literature (18, 29, 33). This might be partly biased by the method of data acquisition, as the diagnosis of a PD was mostly not recorded by a psychiatrist.
Females seemed to suffer more often from an accompanying PD. This finding is in line with data from Ghazinour et al. (29). In contrast, Prescott et al. found no gender-specific difference and Mauri et al. found gender-specific differences concerning specific PDs only (18, 33).
Focusing more closely on the types of PD, depression dominated by far. This corresponds to findings from other studies showing that 65–90% of SRB relating to a PD involve depression (19). Concerning the cases with repeated instances of SRB, a similar pattern could be identified (OR = 6.2; 95% CI 3.8–10.4). Among those, depression was also frequent (OR = 1.4; 95% CI 1.0-1.9).
This aspect together with the increased usage of antidepressants and neuroleptics might explain the relatively high percentage of cases with a history instances of SRB exceeding the findings in literature (29, 33). A PD and the usage of antidepressants and neuroleptics seem associated with repeated suicide attempts (17).
The strong association of addictive disorders and (recurrent) instances of SRB demonstrated in the literature (23, 24) is also supported by the present study in which approximately one-third of the cases of cases with repeated suicide-attempts had an addiction history (OR = 2.5; 95% CI 1.6-4.0).
Furthermore, in line with existing data, the proportion of ethanol addiction is particularly high for cases with recurrent instances of SRB (OR = 2.8; 95% CI 1.6-5.0) (22).
Alongside the finding that the presence of a PD is associated with an increased risk of further SRB, the presence of an (ethanol) addiction seems to constitute a second risk factor for recurrent SRB. Additionally, this study showed that the use of neuroleptics and antidepressants is frequent for cases with repeated instances of SRB. In combination with the finding by Pfeifer et al. who showed that antidepressants, if tricyclic, have a high mortality rate (5), the results could serve to identify potential risk patients at an early stage and to initiate appropriate preventive strategies such as closer monitoring according to their needs. This could involve e.g. psychological intervention (11) or aid to abstinence to reduce impulsivity, a better follow-up observance (23, 24) or a responsible prescription behavior.
Table 4
Overview about literature research with respect to self-intoxication in correlation to age, gender, and substances used
Autor/Year
|
Study design
|
Country
|
Sample size
|
Median age in years (range)
|
Male
|
Female
|
Main substances used
|
Hendrix L et al., 2012 (29)
|
Retrospective study
|
Belgium
|
312
|
37
|
122 (39.1%)
|
190 (60.9%)
|
Benzodiazepine (51%), antidepressants (23%), antipsychotics (16%)
|
Prescott K et al., 2009 (18)
|
Retrospective study
|
UK
|
2665
|
32 (16–90)
|
40.8%
|
59.2%
|
Paracetamol (43%), ibuprofen (17%).
|
Bilén K et al., 2011 (17)
|
Retrospective study
|
Sweden
|
1524
|
39.5
|
35%
|
65%
|
Benzodiazepine (45%), antidepressants (16%), paracetamol (16%)
|
Kordrostami et al., 2017 (34)
|
Forensic toxicology analysis
|
Iran
|
674 (completed suicides)
|
32.61
|
462 (68.55%)
|
212 (31.45%)
|
Aluminium phosphide tablets (pesticides), opioids, methamphetamine
|
Salles et al., 2018 (22)
|
Retrospective study
|
France
|
516
|
42
|
165 (31.9%)
|
351 (68.1%)
|
Benzodiazepine (85%), paracetamol (9%), opioids (4%)
|
Marahatta et al., 2009 (33)
|
Prospective study
|
Nepal
|
54
|
29.87 (females), 35.54 (males)
|
42.6%
|
57,4%
|
Organophosphorus (74%), antidepressants (17%)
|
Mauri et al., 2005 (10)
|
Prospective study
|
Italy
|
201
|
40
|
73 (36%)
|
128 (64%)
|
Benzodiazepine (59%), neuroleptics (13%), antidepressants (13%)
|
Cook et al., 2008 (28)
|
Prospective study
|
UK, Scotland
|
530
|
33
|
35%
|
65%
|
Paracetamol (39%), antidepressants (35%), hypnotics/anxiolytics (25%)
|
Ghazinour et al., 2009 (9)
|
Prospective study
|
Iran
|
2025 (parasuicides)
|
25.4 (females), 28.5 (males)
|
966 (47.7%)
|
1059 (52.3%)
|
Psychotropic drugs and anticonvulsants (56%)
|
Sorge et al., 2015 (16)
|
Prospective study
|
Germany
|
3533
|
35 (males), 29 (females)
|
62.6%
|
37.4%
|
Benzodiazepine (29%), antidepressants (20%), antihistamines (13%)
|
Michel et al., 1994 (30)
|
Prospective study
|
Switzerland
|
Completed suicide: 179
Attempted suicide: 269
|
Completed suicide: 53
Attempted suicide: 36
|
Completed suicide: 49%
Attempted suicide: 35%
|
Completed suicide: 51%
Attempted suicide: 65%
|
Benzodiazepine (CS: 44%, AS: 46%), antidepressants (CS: 16%, AS: 11%)
|