Anxiety disorders characterised by the emotion of anxiety, worrisome thoughts, avoidance behaviour and the somatic symptoms of autonomic arousal (palpitation, chest pain, sweating, dizziness, trembling, shortness of breath and fear of dying).
Among the withdrawal's- anxiety is more crucial, because it can be both challenging and stressful for you. You can get some intense panic attacks and generalised anxiety when you stop. Anxiety develops when your brain is trying to compensate for the THC, received while you used marijuana. Brain will accommodate it within 7 days in most of the cases. So, Withdrawal's are not endless. You just need to wait with patience.
How can you overcome anxiety during withdrawal period?
To relieve anxiety you must try to keep your body busy in the day time. Get out and exercise! Ride your bike, jog, lift weights, anything that gets your body working. It also helps you to get sleep easily without anxiety.
Medications and psychotherapy also helpful to alleviate your symptoms.
Medications for Anxiety -
Anti-depressants, particularly selective serotonin re-uptake inhibitors (SSRI) are widely used to treat and prevent anxiety disorders. SSRI includes citalopram, escitalopram, fluoxetine, paroxetine, and sertraline.
Serotonin and Nor-epinephrine reuptake inhibitors (SNRIs) are newer drugs very-much effective in the treatment of major depressive disorder and mood disorder. But sometimes SNRIs use to treat anxiety also. SNRIs includes Velnafaxine, Sibutramine, Atomoxetine.
Tricyclic antidepressants (TCAs) like Imipramine, may also helpful.
Beta-blockers like Propranolol, commonly used to control physical symptoms of anxiety.
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Panic attacks and anxiety
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Anxiety and panic attacks 
Panic attacks, anxiety and panic disorder
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