The Youth Suicide Rise: Rate Anomalies

The Youth Suicide Rise: Rate Anomalies

Note: this is part of the Youth Suicide Rise project.

The large increase in 2008 brings up another issue to consider: anomalies.

An abnormal event having a strong but short-term effect may need to be analyzed separately when we examine a long-term trend such as the doubling of child suicide.

Let us look again at a graph of proportional changes, this time with direction of change preserved:

We can see that both 2007 and 2017 indicate large proportional changes -- in opposite directions -- from previous year.

Time Period Endpoints

Could it be that the endpoints of our doubling period 2007-2017 were affected by two distinct abnormal events that inflated the long-term trend?

After all, the rates in 2007 and 2017 equal the minimum and the maximum in our data, respectively.

If we look again at the yearly rates graph, however, we will notice a good reason to doubt this possibility, as both 2007 and 2017 fit well with the preceding trend in the graph:

Let us therefore examine how the actual rate each year differed from the rate predicted by the trend set by the previous two years:

For example, the 'expected' rate in 2017 would be 20.8 + (20.8 - 19.0) = 22.6; the actual rate of 24.1 therefore exceeded the predicted rate by less than 7%.

We can see that the year 2017 is unremarkable once trend is taken into account, and that the year 2007 fits its preceding trend perfectly.

The Great Recession

The abnormal event affecting the year 2008 was obviously the Great Recession.  The decrease in the upward trend from 2008 to 2009, and the actual decline in the number of suicides in 2010, are consistent with the economic crisis having strong short-term effects.

It is important to keep in mind, however, that correlation and plausibility are far from causality and proof -- we will analyse links between the recession and child suicide in depth later.

2011

The strong increase in 2011 was followed by 6 years of further increases, so the evidence here does not support an abnormal event with short-term consequences.  Rather, the large increase in 2011 might be better explained as being due to the combination of a rising long-term trend with a rapid recovery from the recession.

Time Period Start: 2007 or 2010?

If the recession affected strongly the years 2008 and 2009, and has unknown long-term effects -- young children experiencing traumatic events such as a parent becoming unemployed or the family house being foreclosed -- the question arises: should we restrict our attention only to developments after 2010?

My view is that unless we can reliably estimate long-term effects of the recession, we should consider both the minimal (negligible recession effects on 2017) and maximal (recession effects remaining at 2010 levels) possibilities and see if a theory is plausible for both, one, or neither scenario.

Notes:

As before, we avoid more advanced statistical tools since their use on so sparse a data set may only lead to a false sense of sophistication.

For those interested, see  How To Identify Patterns in Time Series Data: Time Series Analysis.  If anyone can demonstrate that a more advanced statistical analysis would benefit the discussion in this post, please let me know.

2001 and 2004

The candidate for an abnormal event in 2001 is obviously 9/11.  It may seem paradoxical that such an event could lead to a decrease in suicides, but this was predicted more than a century ago by Émile Durkheim, who noticed that suicide rates are higher in times of peace than in times of war, perhaps due to a 'group cohesion' element countering what Durkheim termed Egoistic suicide.

In 2004, there was a widespread media coverage of studies linking antidepressants to suicidal behavior of adolescents, a concern that culminated with a controversial decision by FDA to require 'black-box' warnings. Somewhat paradoxically again, the consequent decrease in the use of antidepressants has become a suspect for the following spike in adolescent suicides, though it remains unclear if this would have been due to discontinued use rather than due to decrease in new users (a crucial distinction).

None of the above is to imply we have a proof that either of the events explains the trend shift in child suicides in its year -- just the relatively late occurrence of 9/11 within the year should give one a pause.  What I've seen so far published on the subject is mixed and limited in scope.