Consumption of a dietary protein enriched in tryptophan increased the plasma Trp-LNAA ratio and, in stress-vulnerable subjects, improved coping ability, probably through alterations in brain serotonin.

Previous studies have shown selective and nonselective monoamine oxidase inhibitors (MAOIs) to be effective in the treatment of social phobia. In this study we investigated the efficacy of selective serotonin reuptake inhibitors (SSRIs) in social phobia. Thirty patients with social phobia (DSM-IIIR) were treated with the SS-RI fluvoxamine (150 mg daily) using a 12-week double-blind placebo controlled design. A substantial improvement was observed in seven (46%) patients on fluvoxamine and in one (7%) on placebo. Statistically significant effects were seen on measures of social anxiety and general (or anticipatory) anxiety in patients treated with fluvoxamine compared with placebo. The level of phobic avoidance decreased also but the difference at endpoint between fluvoxamine and placebo failed to reach statistical significance. It is concluded that treatment with the SSRI fluvoxamine has beneficial effects in patients suffering from social phobia, suggesting that serotonergic mechanisms might be implicated in social anxiety.

Zohar J, Westenberg HGM. Anxiety disorders: a review of tricyclic antidepressants and selective serotonin reuptake inhibitors. Acta Psychiatr Scand 2000: 101: 39–49. © Munksgaard 2000. Objective: Anxiety disorders are the most common mental health disorders. While the older tricylic antidepressants (TCAs) are efficacious in the treatment of many anxiety disorders, recent studies with fluoxetine and other selective serotonin reuptake inhibitors (SSRIs) have emphasized the role of serotonin in the aetiology of these conditions. Method: We reviewed the efficacy, safety and tolerability of TCAs and SSRIs in the treatment of the most common anxiety disorders, specifically, panic disorder, obsessive‐compulsive disorder, post‐traumatic stress disorder, social phobia and generalized anxiety disorder. Results: Both the TCA and SSRI antidepressants are effective in treating a wide variety of anxiety disorders. SSRIs, due to their greater safety and tolerability, should be the preferred choices in treating anxiety disorders in those instances where TCAs and SSRIs are considered equally effective. In the cases of OCD and social phobia, SSRIs are almost always preferable given that the TCAs do not appear effective in these disorders. Conclusion: Further research is needed on the naturalistic long‐term use of the TCAs and SSRIs in the treatment of anxiety disorders.

Data from animal studies suggest a functional relationship between the cholecystokinin-ergic (CCK) and the serotonergic (5-HT) system. There is increasing evidence that the cholecystokinin-4 (CCK4) challenge test could be a valid experimental model for panic attacks in man. The aim of the present study is twofold; 1) to validate this model further and 2) to shed more light on the putative CCK/5-HT interaction. To this end, we studied the effect of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine on CCK4-induced panic attacks. Twenty-six panic disorder (PD) patients received, before and after a double blind 8-week treatment period with fluvoxamine (n = 17) or placebo (n = 9), a single blind bolus injection with 50 micrograms CCK4. Treatment with fluvoxamine (150 mg daily) significantly decreased the sensitivity of PD patients for CCK4 while placebo was without effect. Of the patients who responded to treatment, 83% no longer experienced a panic attack when rechallenged with CCK4, whereas in the non-responders group this was only 28%. In the fluvoxamine group the treatment response evaluated by the Hamilton Anxiety Scale (HAS) showed a statistically significant treatment effect. The results of this study strengthen the validity of the CCK4 test as an experimental human model for panic attacks and yield evidence supporting the hypothesis that both CCK and serotonin are implicated in the regulation of anxiety.

No abstract

In order to evaluate serotonin (5-HT) function in panic disorder, a double blind placebo controlled study was conducted with ritanserin, a specific 5-HT2 receptor antagonist, and fluvoxamine, a selective 5-HT reuptake inhibitor, in 60 patients with panic disorder. Patients were treated for 8 weeks with 150 mg fluvoxamine, 20 mg ritanserin or placebo; these dose levels were reached after 1 week. In addition, as an index of 5-HT function in panic disorder, plasma concentration of beta-endorphin, cortisol and 5-hydroxyindolacetic-acid (5-HIAA) were measured. Furthermore, 5-HT uptake in blood platelets was assessed. Noradrenergic function was assessed by measuring plasma MHPG concentration. In addition, plasma melatonin concentration was measured. Treatment with fluvoxamine resulted in a profound reduction in the number of panic attacks, followed by a decrease in avoidance behavior. Treatment with ritanserin appeared to be ineffective. During treatment no significant changes were observed in plasma concentrations of beta-endorphin, cortisol, 5-HIAA and MHPG. With respect to 5-HT kinetics in blood platelets, a substantial increase in Km was observed after treatment with fluvoxamine, whereas Vmax decreased. After treatment with fluvoxamine, plasma concentration of melatonin was significantly increased, which suggests that melatonin synthesis is in part under serotonergic control. The findings of the present study do not support the hypothesis that 5-HT2 receptors are supersensitive in patients suffering from panic disorder, but allow no conclusions about the involvement of other 5-HT receptor subtypes.

No abstract

Psychiatry 1995;58:614-617)