Nicotine fights fear, anxiety, PTSD

Tobacco smoking produces widespread dominant brain wave alpha frequency increases
After the subjects smoked a favorite tobacco cigarette there was a significant generalized increase in dominant alpha EEG frequencies in most scalp recording sites. This study demonstrates that tobacco smoking produces widespread bilateral neocortical increases in dominant alpha EEG frequencies consistent with the stimulant effects of nicotine on the brainstem reticular activating system.
[link to www.ncbi.nlm.nih.gov]

Smoking tobacco has a similar effect with meditation in regarding the alpha brainwaves. Smoking prevents people to become mentally agitated and zombielike.

Indeed!

The first metabolite of nicotine, unimaginatively titled cotinine, was a prescription antidepressant until the 1960's.

The proof that smoking upregulates VMAT2:

Mice were injected with nicotine free base 2mg/kg, sc, four times daily for 14 days and killed 12-72h after drug discontinuation. VMAT2 protein was increased in the striatum of nicotine-treated mice in a time-dependent fashion at all times studied. Furthermore, in situ hybridization studies demonstrated that VMAT2 mRNA was elevated in the substantia nigra pars compacta and ventral tegmental area, indicating enhanced gene expression and subsequent protein synthesis.
[link to europepmc.org]

The ensemble of studies to date suggest that under certain conditions nicotine can act as an anxiolytic and an antidepressant, but that following chronic use, adaptations to nicotine can occur resulting in increased anxiety and depression following withdrawal.
[link to www.ncbi.nlm.nih.gov]

Psychiatric research has documented that enhanced noradrenergic postsynaptic responsiveness in the neuronal pathway (brain circuit) that originates in the locus coeruleus and end in the basolateral nucleus of the amygdala is a major factor in the pathophysiology of most stress-induced fear-circuitry disorders and especially in posttraumatic stress disorder (PTSD). The LC neurons are probably the origin of the first or second “leg” of the "PTSD circuit." An important 2005 study of deceased American army veterans from World War II, was shown combat-related PTSD to be associated with a postmortem diminished number of neurons in the locus coeruleus (LC) on the right side of the brain.
The locus coeruleus may figure in clinical depression, panic disorder, and anxiety.
The locus coeruleus is activated by stress, and will respond by increasing norepinephrine secretion, which in turn will alter cognitive function.
[link to en.wikipedia.org]

Systematically administered nicotine in low doses increases the firing rate of rat locus coeruleus (LC) neurons. In the present study, this action of nicotine was found to be prevented by pretreatment with kynurenic acid (1 μmol; i.c.v.).
[link to www.sciencedirect.com]

Contrary to a widely accepted theory, increased activity of locus coeruleus (LC) neurons does not appear to potentiate anxiety; instead, the influence of LC activity may be opposite to this.
[link to www.ncbi.nlm.nih.gov]

Previous electrophysiological experiments have shown that the marked but short-lasting excitation of locus coeruleus (LC) neurons seen after systemic administration of low doses of nicotine is of a peripheral origin. In addition, nicotine induces a weak but more long-lasting activation of LC neurons which is preferentially observed following administration of high doses of the drug.
[link to link.springer.com]

Cigarette smoking calms the nerves and gives you confidence
[link to www.youtube.com]

There might be something to this. I have PTSD from some pretty nasty things that happened to me during my childhood and as an adult. I chew nicotine gum and have noticed a marked decrease in PSTD symptoms for the past 3 1/2 years I've been chewing. It doesn't alleviate symptoms when I'm in periods of extreme stress but now that I think of it the nicotine helps! Figures, I quit smoking and now I'm addicted to the gum. My doctor says its still better than smoking.

There was also a recent study by a Medical University in the US (Carolina?- will see if I can find it) where the results showed nicotine improves memory.
They are now conducting studies with Altzheimer patients, with strong indications that the degenerative effects of the disease can be halted or slowed down, and in some cases reversed to some degree.

MDMA and it's cousins do it a billion times better and are non addictive.