Suicide is a big public health concern, leading to almost 6000 deaths in the UK alone in 2012 (Samaritans, 2014) – successful intervention should therefore be a priority. As suicidal ideation frequently occurs alongside depression, it is often the depression itself that is targeted by treatment programs. However, due to limited research it is unclear whether this is actually the best way to decrease the risk of suicide.

This paper aimed to provide more information on treating suicide by assessing the effects of common treatments of depression in reducing suicidal ideation (Weitz et al, 2014).

Methods

The study used data gathered through the Treatment of Depression Collaborative Research Program (TDCRP) (Elkin et al, 1989). This original study included 239 participants who met diagnostic criteria for major depression over at least the last 2 weeks. Participants were excluded if they had additional psychiatric disorders or were at high-risk of suicide. Participants were randomly assigned to one of four 16-week long treatment conditions:

1. Interpersonal therapy
2. Cognitive behavioural therapy
3. Pharmacotherapy with imipramine (a tricyclic antidepressant)
4. Placebo

All original participants completed ratings on the Hamilton Rating Scale for Depression (HRSD) and Beck Depression Inventory (BDI). Data from participants scoring 1 or greater on either of these scales were included in the present study. 146 participants had the required score on the HRSD and 147 on the BDI and so were included.

A series of statistical tests were then run on the data to assess the effects of each treatment. ANOVAs and chi-squared tests found no differences pre-treatment in the four treatment groups in terms of age, gender, mean depression scores, marital status or education levels. Paired T-tests investigated pre- and post-treatment suicide scores and effect sizes were also calculated. Multiple regressions were then performed to assess the effects of treatment on suicide scores after accounting for changes in depression scores.

Results

• All treatment groups showed a significant decrease in suicide scores on both the HRSD and BDI after treatment compared with pre-treatment.
• These effects (using Cohen’s d) were all of medium size, though interpersonal therapy had the largest at 0.56 and placebo the smallest at 0.34.
• Interpersonal therapy and treatment with medication were both significantly better than placebo at reducing suicide scores as measured on the HRSD. All treatments appeared to perform similarly when suicide scores were measured on the BDI. Changes in suicide scores on both the HRSD and the BDI were significantly related to changes in depression scores.
• Changes in suicide scores for interpersonal therapy vs. placebo and medication vs. placebo were no longer significant once changes in depression scores had been taken into account.

Conclusion

The authors concluded that there is evidence for:

the specific effectiveness of interpersonal therapy and medication in reducing suicidal ideation, albeit largely as a consequence of their more general effects on depression.

Although this is a promising finding, this study was limited by its reliance on the TDCRP sample (as noted by the authors). Even though the present study was investigating suicide, participants at high risk of suicide or who made an attempt at suicide were excluded from the original sample. This means that the current study only assesses treatment of mild to moderate suicidal ideation and so is inherently limited in its ability to evaluate the best treatment for the full range of suicidal behaviours. Furthermore, suicidal ideation was only measured by one item on each depression scale used in the TDCRP and so may not give a complete picture of each participant’s suicidality.

This study contributes a little to increasing the understanding of the best treatment for reducing suicidal ideation, but further research is needed to clarify this relationship.

If you need help

If you need help and support now and you live in the UK or the Republic of Ireland, please call the Samaritans on 116 123.

If you live elsewhere, we recommend finding a local Crisis Centre on the IASP website.

We also highly recommend that you visit the Connecting with People: Staying Safe resource.

Links

Weitz E, Hollon SD, Kerkhof A, Cuijpers P. Do depression treatments reduce suicidal ideation? The effects of CBT, IPT, pharmacotherapy, and placebo on suicidality. J Affect Disord. 2014 Jun 2;167C:98-103. doi: 10.1016/j.jad.2014.05.036. [PubMed abstract]

Elkin I, Shea MT, Watkins JT, Imber SD, Sotsky SM, Collins JF, Parloff MB. (1989) National Institute of Mental Health treatment of depression collaborative research program: General effectiveness of treatments. Archives of General Psychiatry, 46(11), 971-982.

Samaritans. (2014). Suicide statistics report 2014: Including data for 2010-2012.