Sub-study III set out to examine socioeconomic differences in psychiatric treatment before and after an episode of hospital-presenting self-harm in adolescence or young adulthood. The study used two main outcomes, inpatient or outpatient specialised healthcare use due to psychiatric disorders, and any psychotropic medication purchases. Individuals were followed in three-month periods for two years before and after the episode of hospital-presenting self-harm. In total, there were 4,280 individuals in the study (64% girls), and 81% of the examined self-harm episodes were self- poisonings.
Figure 10 shows the predicted probabilities of psychiatric treatment from logistic GEE models. Separate curves for parental education were estimated by including an interaction term between time dummies and parental education into the model. The index month of self-harm was omitted from the trajectory analyses for two reasons. First, the index month was used as one time point, whereas other time points consisted of three calendar months. Thus, the length of the period is discrepant when compared to others. Moreover, specialised treatment was highly common during the index month, which clouds differences between the educational groups in graphical presentation of the results.
There was a clear socioeconomic gradient in psychiatric treatment use by parental education: the higher the parental education, the higher the predicted treatment use (Figure 10). This pattern was especially clear in specialised psychiatric healthcare use after the episode of self-harm. At the start of the follow-up, two years before self-harm, the predicted probability of specialised healthcare use was 0.14 (95% CI: 0.10, 0.17) among those whose parent had basic education and 0.15 (95% CI: 0.12, 0.18) among adolescents whose parent had higher tertiary education. From there, these groups started to diverge in terms of probability of specialised treatment. At time point 1–3 months before self-harm, the probability of specialised healthcare use was 0.24 (95% CI: 0.20, 0.28) among adolescents whose parents had basic education, and 0.36 (95% CI: 0.32, 0.40) among adolescents whose parents had higher tertiary education. At time point 1–3 months, the corresponding probabilities were 0.32 (0.27, 0.36) and 0.42 (0.38, 0.47), respectively. After self-harm, the probability of specialised healthcare use decreased in all the parental education groups, but these socioeconomic differences persist until the end of follow-up, where the probability of specialised healthcare use was 0.20 (0.16, 0.23) in the group of basic parental education and 0.28 (0.24, 0.32) in the group of higher tertiary parental education. During the whole- follow-up, the probabilities of specialised healthcare use in groups with parental secondary or lower tertiary education fell in between these two groups at the ends of the educational distribution of the parents.
Figure 10 Three-month predicted probabilities of psychiatric treatment before and after self- harm. Note that the month of self-harm is omitted from the analysis.
In psychotropic medication use, the group differences before self-harm were negligible and inconsistent but a gradient by parental education emerged after self-harm. In all the groups, the probabilities of psychotropic
medication purchases were around 0.15 at the start of the follow-up, but at time point 1–3 months there was a difference of around 10 percentage points in the probability of psychotropic medication purchases between those whose parents had basic level of education (predicted probability 0.36; 95% CI:
0.32, 0.40) and those whose parents had higher tertiary education (0.47;
95% CI: 0.42, 0.52). The probabilities of psychotropic medication purchases gradually decreased after self-harm and were 0.30 and 0.35 at the end of the follow-up among those in the lowest and highest parental education groups, respectively. However, the differences in probabilities between those with highest and lowest parental education persisted until the end of follow-up
Results
probabilities of psychotropic medication purchases in the groups of parental secondary education and parental lower tertiary education were mostly in between the probabilities in the groups at the ends of the educational distribution of the parents.
The trajectory-based approach with predicted probabilities calculated at different time points does not take into account whether the individuals using treatment at each time point are the same. Therefore, cumulative treatment use during different time periods was also assessed. The
cumulative measure also allows for differentiating between different types of treatment, which is useful since individuals might be treated in inpatient or outpatient settings, they may use medication only, or a combination of healthcare and medication. For the purposes of the cumulative treatment use investigation, a categorical outcome consisting of inpatient treatment, outpatient treatment, medication only and no treatment was constructed in different time periods during the follow-up. Socioeconomic differences in group membership were assessed with multinomial models. The results for the group who did not use any treatment are presented in Figure 11, again as predicted probabilities.
There was an educational gradient in not using any treatment, and this gradient was present one month, one year, and two years before and after self-harm (Figure 11). The gradient was similar to the one observed in the trajectories: the lower the parental education, the higher the probability of not receiving any treatment. Among the adolescents in the lowest parental education group, the probabilities of not using any treatment two years before, one year before or a month before were 0.39, 0.45 and 0.74, respectively, while the corresponding probabilities among those in the highest group of parental education were 0.29, 0.32 and 0.61.
The probability of not using any treatment during the two years following self-harm was 0.29 among those in the lowest group of parental education, whereas in the highest parental education group the corresponding
probability was 0.18. Similar differences were also found in not using
treatment a year after self-harm (probability 0.34 among those with parental basic education and 0.22 among those with parental higher tertiary
education) and a month after self-harm (probabilities 0.67 and 0.55 among those in the groups of lowest and highest parental education, respectively).
The probabilities of not using any treatment in the other groups of parental education were again in between the groups of lowest and highest parental education.
Among those who received some treatment, the differences by parental education in medication purchases and outpatient treatment use were quite small, except for psychiatric outpatient healthcare use one month after self- harm, where parental higher education increased the likelihood of using
treatment (results in the original publication). In cumulative inpatient use one and two years before and after, there was also a similar gradient by parental education, as higher parental education increased the likelihood of having been treated in psychiatric inpatient care (results in the original publication).
Figure 11 Predicted probabilities of not receiving any psychiatric treatment cumulatively up to different time points relative to self-harm
Results