Agomelatine in Panic Disorder: A 6-Week Follow-Up Case Series

Panic Disorder Correlates With the Risk for Sexual Dysfunction

BACKGROUND

Reports have suggested that sexual dysfunction is an underestimated complication of panic disorder, but little research has focused on sexual dysfunction associated specifically with panic disorder. The purpose of this systematic review was to investigate whether patients with panic disorder who are not currently receiving treatment had a higher risk of sexual dysfunction than healthy people, as well as to clarify the appropriate treatment for this patient group.

METHODS

Articles that reported panic disorder complicated with sexual dysfunction were identified by a systematic literature search of electronic databases, including PubMed, the Cochrane databases, EMBASE, and PsycINFO.

RESULTS

Six articles were included in the review. Patients with panic disorder showed a high prevalence of sexual aversion (35.7% to 64%) and sexual infrequency (36% to 44%). One cohort study indicated that untreated patients with panic disorders had a higher risk of erectile dysfunction than controls. Another article that focused specifically on female patients reported that the patients with panic disorder exhibited decreased frequency of sexual behavior and decreased sexual desire compared with the controls. However, 2 studies found conflicting results after adjustment for confounding factors.

CONCLUSIONS

Although the results were mixed, it appears that patients with panic disorder tended to be more susceptible to sexual dysfunction than the general population. Further trials with larger sample sizes and rigorous research designs are needed to establish the relationship between sexual dysfunction and panic disorder.

Neuroinflammation and the Immune-Kynurenine Pathway in Anxiety Disorders

BACKGROUND

Recently, neuroinflammation and the immune-kynurenine pathway have received increased attention in the psychoimmunology field of major depressive disorder (MDD), while studies related to anxiety disorders have been very limited.

OBJECTIVE

This study reviewed possible mechanisms by which stress or inflammation modulate anxiety through tryptophan metabolism and the kynurenine pathway.

METHODS

Relevant literature was identified through a search of MEDLINE via PubMed.

RESULTS

Accumulating evidence has indicated the modulatory effects of the immune-kynurenine pathway on anxiety. The tryptophan catabolites (TRYCATs) in the kynurenine pathway imbalanced by stress or inflammation induce serotonin and melatonin deficiency, making anxiety reactions more sensitive. In addition, TRYCATs cause or sustain anxiety by acting as endogenous anxiogens or anxiolytics, an NMDA agonist or antagonist, or a free radical generator.

CONCLUSION

We hope that our understanding of the psychoimmunological mechanisms of anxiety will be expanded and anxiety-related studies will receive greater attention.

Functional neuroanatomy in panic disorder: Status quo of the research

AIM

To provide an overview of the current research in the functional neuroanatomy of panic disorder.

METHODS

Panic disorder (PD) is a frequent psychiatric disease. Gorman et al (1989; 2000) proposed a comprehensive neuroanatomical model of PD, which suggested that fear- and anxiety-related responses are mediated by a so-called “fear network” which is centered in the amygdala and includes the hippocampus, thalamus, hypothalamus, periaqueductal gray region, locus coeruleus and other brainstem sites. We performed a systematic search by the electronic database PubMed. Thereby, the main focus was laid on recent neurofunctional, neurostructural, and neurochemical studies (from the period between January 2012 and April 2016). Within this frame, special attention was given to the emerging field of imaging genetics.

RESULTS

We noted that many neuroimaging studies have reinforced the role of the “fear network” regions in the pathophysiology of panic disorder. However, recent functional studies suggest abnormal activation mainly in an extended fear network comprising brainstem, anterior and midcingulate cortex (ACC and MCC), insula, and lateral as well as medial parts of the prefrontal cortex. Interestingly, differences in the amygdala activation were not as consistently reported as one would predict from the hypothesis of Gorman et al (2000). Indeed, amygdala hyperactivation seems to strongly depend on stimuli and experimental paradigms, sample heterogeneity and size, as well as on limitations of neuroimaging techniques. Advanced neurochemical studies have substantiated the major role of serotonergic, noradrenergic and glutamatergic neurotransmission in the pathophysiology of PD. However, alterations of GABAergic function in PD are still a matter of debate and also their specificity remains questionable. A promising new research approach is “imaging genetics”. Imaging genetic studies are designed to evaluate the impact of genetic variations (polymorphisms) on cerebral function in regions critical for PD. Most recently, imaging genetic studies have not only confirmed the importance of serotonergic and noradrenergic transmission in the etiology of PD but also indicated the significance of neuropeptide S receptor, CRH receptor, human TransMEMbrane protein (TMEM123D), and amiloride-sensitive cation channel 2 (ACCN2) genes.

CONCLUSION

In light of these findings it is conceivable that in the near future this research will lead to the development of clinically useful tools like predictive biomarkers or novel treatment options.