Lithium carbonate decreases acute suicidality in posttraumatic stress disorder

To the Editor

Posttraumatic stress disorder (PTSD) has been associated with higher rates of suicidal ideation and suicide attempts (Krysinska and Lester, 2010); however, there are very few studies of the treatment of suicidality in PTSD. Higher rates of suicidality in PTSD may be due to the emotion regulation problems which can accompany both PTSD (Weiss et al., 2012) and suicidality. We describe two patients with histories of suicide attempts and primary Axis I diagnosis of PTSD with delayed onset (American Psychiatric Association, 2000), whose suicidality improved significantly after 3–4 weeks of lithium therapy. Patients were monitored with the Beck Scale for Suicide Ideation (BSS) (Beck and Steer, 1991) and the Clinician-Administered PTSD Scale (CAPS) (Weathers, 2004). Consent was obtained from the Office of Research Ethics, University of Western Ontario, Canada.

Patient A is a 55-year-old woman who presented with panic attacks, insomnia, nightmares and flashbacks of childhood sexual abuse. She experienced intrusive thoughts about stabbing herself with a knife when her PTSD symptoms were triggered; on one occasion, she had checked herself into a hotel and started to cut herself, when she thought of her children and decided to call the ambulance instead. Lithium carbonate 300 mg twice a day was initiated. At the 3-week follow-up she reported a significant decrease in her suicidal thoughts. Her serum lithium level was 0.6 mmol/L. From pre-lithium to 3-week post-lithium therapy there was a decline in both BSS (28 versus 10) and CAPS (118 versus 69) scores. The patient has remained on lithium carbonate and has maintained improvement in her suicidality at the 18-month follow-up.

Patient B is a 50-year-old woman who first started experiencing marked anxiety, panic attacks, insomnia, nightmares and flashbacks of childhood sexual abuse at age 45. During her acute flashbacks, she experienced intense suicidal impulses and was hospitalized with a serious drug overdose on two occasions. The patient was started on lithium carbonate 150 mg twice a day and 600 mg every night at bedtime and followed up in 4 weeks. From pre-lithium to 4-week post-lithium therapy there was a decline in both BSS (38 versus 0) and CAPS (116 versus 71) scores, with a serum lithium level of 0.7 mmol/L. The patient has remained on lithium carbonate and maintained improvement in her suicidality 1 year later; during this period, she has been able to participate in a PTSD group therapy program for the first time.

Previous studies of mood stabilizers (e.g. sodium valproate) in PTSD have tended to consider the presence of suicidal ideation to be an exclusion criterion. Furthermore, prior to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, suicidal ideation was not included as a diagnostic feature of PTSD and therefore standard assessment tools, such as the CAPS, have not included suicidality as an outcome measure.

These two case studies indicate a significant beneficial effect of lithium carbonate at 600–900 mg daily (serum lithium levels = 0.6–0.7 mmol/L) on acute suicidality in PTSD. This has not been previously reported. Lithium therapy was associated with a substantial and rapid improvement in suicidality; however, PTSD symptoms improved moderately but remained in the clinical range (i.e. CAPS scores > 45).