It almost goes without saying that the first step in deciding whether or not to begin a course of anti-anxiety medication is to make (in the case of the clinician) or have (in the case of the patient) the diagnosis of anxiety! Having said that, there is a distinct difference between anxiety as a symptom and anxiety as a disorder. Thus, the symptom of anxiety is defined in Campbell’s Psychiatric Dictionary as “An affect that differs from other affects in its specific unpleasurable characteristics.” The DSM 5 (Diagnostic and Statistical Manual 5th edition published by the American Psychiatric Association) which is considered “The Psychiatrist’s diagnostic “bible,” states that “anxiety is anticipation of a future threat.” Going back to Campbell’s, it goes on to say that “Anxiety consists of a somatic, physiological side…and of a psychological side.” An Anxiety Disorder per the DSM “includes[s] disorders that share features of excessive fear (‘the emotional response to real or perceived imminent threat’). A non-inclusive list of anxiety disorders is thus: Phobias (including Social and Specific types like to spiders), Panic Disorder, Agoraphobia, and Generalized Anxiety Disorder. Obsessive-compulsive disorder (including subtypes like Hoarding Disorder and Trichotillomania or hair-pulling) which used to be in the anxiety disorder realm now merits their own diagnostic classification in the newest DSM.
Once the diagnosis of anxiety-disorder is made, the next order of business is treatment. Before the various medications for these disorders is discussed, it is crucial to understand that the best treatment for the underlying disorder remains non-chemical: included here are the various types of psychotherapy or counselling as well as ancillary treatments like meditation, relaxation techniques, exercise and nutrition. Thus, if medication treatment is started and the patient does not undertake treatment for the underlying problem, then quite often when the medications are stopped the anxiety symptoms will-reappear, making it crucial to utilize non-medication treatment for the underlying anxiety/disorder.
That being said, the anti-anxiety medications can be grouped into: the anti-depressants (which are rightfully called anti-anxiety agents as well), a category of miscellaneous or other (antihistamines, and other non-benzodiazepine alternatives) and the benzodiazepines (often called for short “benzo’s”).
First, the antidepressants: It must be said that the term itself of antidepressant must be considered an anachronism1 in that many of these medications are approved by the FDA (Food and Drug Administration) for various anxiety disorders. Included here are the SSRI”s (selective serotonin reuptake inhibiters): Prozac (fluoxetine), Paxil (paroxetine), Zoloft (sertraline), Celexa (citalopram), Lexapro (escitalopram) and Luvox (fluvoxamine) (as well as the “dual reuptake inhibiters Cymbalta (duloxetine), Effexor (venlafaxine) and Pristiq (desvenlafaxine) Also the older anti-depressants including Desyrel (trazadone), Remeron (mirtazapine), Clomipramine (anafranil) , Doxepin (Sinequan) and the MAO-I’s (Marplan, Nardil, and Parnate) are all utilized (“off-label”*) for anxiety treatment.
The three non-benzodiazepine medications often used to treat anxiety for those patients who may, for instance, be at risk to become dependent on the potentially addictive benzo’s include beta-blocker’s like Inderal (generic propranolol), Neurontin (gabapentin) and Buspar (buspirone).
First, let us look at the value of the drug Inderal as an anti-anxiety medication. Inderal, although not Food and Drug Administration (FDA) approved for this indication* is the drug of choice for syndromes such as public speaking or test-taking anxiety. Performers or test-takers thus find that for instance 20-40 milligrams (mg) of this drug an hour or two prior to the anxiety-provoking event does wonders. Inderal also comes in a long acting form (Inderal LA) and if found to be efficacious can be given around the clock as well as the regular or immediate release Inderal that can be used “on top of” the long acting Inderal should an acute anxiety provoking situation occur or have the potential to occur. It works by blocking beta receptor sites in the nervous system and body in general in order to decrease the physical symptoms of anxiety (e.g., palpitations, accelerated heart rate and other symptoms due to adrenaline over-activity in the adrenals and elsewhere). Studies clearly show that as opposed to intuitive reasoning, when anxious it is the bodily symptoms which occur first at which point the subconscious mind detects that the person has become anxious. The usual dose of Inderal is 10-49 milligrams (mg) 20-30 minutes prior to the anxiety provoking event.
In the same ballpark as Inderal is Catapres (generic clonidine), in that it too is an old time cardiovascular drug whose effect it has on receptors (termed presynaptic α2 noradrenergic type) serves to treat anxiety and panic attacks.2 As opposed to Inderal, Catapres seems to have more of a direct effect on the brain/mind’s perception of anxiety rather than the bodily symptoms thereof. It also happens to be the drug of choice for anxiety symptoms associated with opiate withdrawal (heroine, methadone, pain pills, etc.).
Neurontin has been found in several research studies 3 to be effective for anxiety including social phobia and panic attacks as well as those anxious patients with the diagnosis of bipolar disorder. It can be used as a stand-alone treatment for anxiety or in combination with other anti-anxiety medications.
Buspar is an old-time drug approved by FDA for treatment of anxiety, particularly GAD or generalized anxiety disorder. It is a good example of just how complex these drug mechanisms of action can be and the difficulty in extrapolation to clinical effect. For instance, Wikipedia tells us that Buspar works at no less than a half-dozen different receptor sites at various parts of the nervous system including from the higher level functioning neocortex to the more primitive brainstem.
*Most medications in the United States are prescribed off-label meaning it is up to the Dr’s discretion as to which medications to use for what indication. The fact that the Food and Drug Administration (FDA) has approved an indication also means that the drug in question must have been “proven” to work statistically in a clinical trial. Once a drug goes generic, it makes it much less likely that the drug company will pay to have it studied, so that FDA approved indications are somewhat of an artifact of this “political”-type process.
Buspirone functions as a serotonin 5-HT1A receptor partial agonist (IA = 0.465). It is this action that is thought to mediate its anxiolytic and antidepressant effects. Additionally, it functions as a presynaptic dopamine antagonist at the D2, D3 and D4 receptors.  Buspirone is also a partial α1 receptor agonist. Buspirone also appears to produce some oxytocin stimulation via 5-HT1A receptor-induced action. Buspirone binds to 5-HT type 1A serotonin receptors on presynaptic neurons in the dorsal raphe and on postsynaptic neurons in the hippocampus, thus inhibiting the firing rate of 5-HT-containing neurons in the dorsal raphe. Buspirone also binds at dopamine type 2 (DA2) receptors, blocking presynaptic dopamine receptors. Buspirone increases firing in the locus ceruleus, an area of brain where norepinephrine cell bodies are found in high concentration. The net result of buspirone actions is that serotonergic activity is suppressed while noradrenergic and dopaminergic cell firing is enhanced. [4
Arch Gen Psychiatry. 1981;38(11):1278-1282.
A)Frye MA, Ketter TA, Kimbrell TA, et al. A placebo-controlled study of lamotrigine and gabapentin monotherapy in refractory mood disorders. J Clin Psychopharmacol. 2000 Dec;20(6):607-14
B)Neurontin: Does it Work for Anxiety? By The Carlat Psychiaty Report