RESEARCH UPDATE
CASE VIGNETTE
“Mr Herringbone” is a 29-year-old Caucasian male with a historical past of main depressive dysfunction (MDD), recurrent, extreme, with out psychosis. The onset of his despair was round age 12. He has some options of atypical despair, together with hypersomnia, weight acquire, and anxiousness. Mr Herringbone beforehand failed trials of sertraline, escitalopram, bupropion, venlafaxine, nortriptyline, lamotrigine, lithium, liothyronine, aripiprazole, and perphenazine. He additionally had a quick course of transcranial magnetic stimulation, with some early enchancment, however was unable to proceed on account of insurance coverage points. He declined electroconvulsive remedy (ECT) on account of his father having vital adversarial cognitive results from the process. He skilled partial response to fluoxetine 80 mg every day and amphetamine-dextroamphetamine extended-release 20 mg every day. He had genetic testing, which confirmed that he’s heterozygous for the quick/lengthy promoter polymorphism of the serotonin transporter gene, a standard metabolizer of CYP 1A2, 2D6, and 3A4, and homozygous for the C allele of the C677T polymorphism of the MTHFR gene (regular folic acid metabolism). He was provided trials of L-methylfolate, tranylcypromine, and clozapine. Subsequently, Mr Herringbone has responded to 100 mg clozapine every day, with vital enchancment in temper and anxiousness.
Roughly 15% of sufferers with MDD don’t reply to satisfactory pharmacotherapy, psychotherapy, and neurostimulation.1 Sadly, in latest many years there have been restricted advances within the medical administration of treatment-resistant despair (TRD). Just lately, there was an emphasis on ketamine and neuromodulatory remedies in TRD. A novel diagnostic and therapeutic method to TRD primarily based on a focused evaluation of blood, urine, and CSF metabolites has been proposed. For instance, Pan and colleagues reported on a 19-year-old male with TRD and repeated suicide makes an attempt who had poor CSF tetrahydropiopterin (BH4) intermediates and responded to substitute with the BH4 analog sapropterin.2 In a case-control research, this group discovered doubtlessly treatable metabolite abnormalities in 21 of 33 sufferers with TRD and nil controls.3
The Present Research
Pan and colleagues carried out a scientific analysis of 141 sufferers with TRD and controls for main and secondary issues of CNS metabolism.4 They recruited n=141 members aged 14 to 70 with despair unresponsive to a minimum of 3 most dose medicine trials of a minimum of 6 weeks. These members had been in comparison with n=36 wholesome controls with no private or first-degree relative historical past of psychiatric dysfunction or suicidal conduct. Members had been assessed with a structured psychiatric interview, together with the Household Interview for Genetics Research. TRD standing was confirmed with the Antidepressant Remedy Historical past Questionnaire. Members had been additionally assessed with the Beck Despair Stock (BDI) and Suicide Ideation Questionnaire (SIQ), and continued all present drugs and different remedies through the research. Members had blood and urine testing, in addition to a lumbar puncture for CSF assortment, and a follow-up appointment to evaluate outcomes and supply further referrals. Members for whom a novel therapy was accessible had been recontacted a minimum of 6 weeks after the beginning of that therapy. TRD and management teams had been in contrast with t-tests and chi-square check. Paired t-tests had been carried out for topics with cerebral folate deficiency.
Imply participant age was 27.5, 39% had been male, and 86% had been Caucasian. Virtually half of the TRD members reported a historical past of a minimum of 1 suicide try. Sixty seven of 141 members with TRD (48%) had proof of metabolomic abnormalities. Cerebral folate deficiency (CFD), through which serum folate is regular however CSF 5-MTHF is low, was current in 20 members (14%). Low (n=11) and borderline low (n=20) CSF BH4 intermediates had been additionally widespread. Irregular serum acylcarnitine profiles (n=12) and serum amino acids (n=20) had been additionally discovered. Eighteen members (13%) had 2 or extra metabolic findings.
Twenty members with low CSF 5-MTHF had been provided folinic acid, of whom 16 had been handled for a minimum of 6 weeks. All 16 of those members with CFD confirmed discount in SIQ scores (40 to 23) and 15 confirmed discount in BDI scores (31 to 18.5). Eleven members with low CSF BH4 intermediates had been provided sapropterin, of whom 7 had been handled for a minimum of 6 weeks. All 7 confirmed discount in SIQ scores (60 to 38) and BDI scores (43 to twenty-eight). Twenty members with borderline low CSF BH4 intermediates had been provided sapropterin, of whom 5 had been handled for a minimum of 6 weeks. All 5 confirmed discount in SIQ scores (41 to twenty) and BDI scores (30 to 16).
Research Conclusions
The authors systematically evaluated abnormalities of neurotransmitter, vitamin, pterin, and vitality metabolism in peripheral and CSF samples in topics with TRD. They discovered that nearly half (48%) of those members had metabolic abnormalities, and signs of despair and suicide improved when related focused remedies had been accessible. Though they didn’t deal with sufferers with irregular serum acylcarnitine profiles, they hypothesize that therapy with riboflavin 100 mg every day is perhaps useful. Research limitations included the comparatively small pattern of primarily Caucasian members, and the absence of a proper therapy trial for these with recognized abnormalities. Future instructions embrace repeat metabolic testing, together with after intervention, and evaluating sufferers with TRD to treatment-responsive sufferers.
The Backside Line
Neurometabolic abnormalities are widespread, and infrequently actionable and clinically related in sufferers with TRD. Identification of genetic and secondary metabolic issues contributing to psychiatric sickness could enable orphan drug repurposing for TRD.
Dr Miller is professor within the Division of Psychiatry and Well being Habits, Augusta College, Augusta, Georgia. He’s on the Editorial Board and serves because the schizophrenia part chief for Psychiatric TimesTM. The creator stories that he receives analysis help from Augusta College, the Nationwide Institute of Psychological Well being, and the Stanley Medical Analysis Institute.
References
1. Nameless. The burden of despair. Nature. 2014;515(7526):163.
2. Pan L, Martin P, Zimmer T, et al. Neurometabolic issues: doubtlessly treatable abnormalities in sufferers with therapy refractory despair and suicidal conduct. Am J Psychiatry. 2017;174(1):42-50.
3. Pan L, McKain BW, Madan-Khetarpal S, et al. GTP-cyclohydrolase deficiency aware of sapropterin and 5-HTP supplementation: Aid of treatment-refractory despair and suicidal behaviour. BMJ Case Rep. 2011;2011:bcr0320113927.
4. Pan LA, Segreti AM, Wrobleski, et al. Metabolomic issues: confirmed presence of probably treatable abnormalities in sufferers with therapy refractory despair andsuicidal conduct. Psychol Med. 2022;1-9.