Conceiving and validating anxiety models in healthy subjects (HV) and patients was needed for cost- and time effective drug development to support novel chemical entities characterised in preclinical models of anxiety. Some substances or conditions as inhalation of CO₂ are panicogen in man and can reproduce in healthy subjects core symptoms of panic attack similar to those reported in Panic Disorder patients. A model was developed by generating anxiety symptoms in HV through the administration of 7% CO2 for 20min. HV were given in balanced order 7% CO2 or compressed air as control condition in two separate sessions and this challenge, in comparison with compressed air, produces measurable response (Panic Symptom list (PSLIII-R), Visual scale (VAS-A), STAI Anxiety Inventory (STAI-Y/1), respiratory parameters and skin conductance) in susceptible subjects. The model was validated by applying this challenge before and after the administration of alprazolam, a drug known to reduce anxiety symptoms, which resulted to be able to reduce subjective and objective symptoms. In conclusion, evoking anxiety symptoms by a 7% CO₂ challenge with good test-retest repeatability in healthy subjects is a reliable model to test potential anxiolytic effects of a new chemical compound.

The receptor for capsaicin, designated vanilloid receptor subtype 1 (VR1) works as a general sensor of noxious stimuli and id expressed in both the peripheral and central nervous system within centers known for their role in pain detection, transmission and regulation. Capsaicin cream was administered to the skin of the volar forearm during each study visit, at a site approximately 10 to 15 cm from the wrist and left for 30 minutes. Quantitative sensory testing with a Neuro-Sensory Analyzer was allowed for registering the heat perception threshold and the heat pain perception before and after the capsaicin administration. The Heat Perception Threshold (HPT) and the Pain Perception Threshold (HPPT) was measured using the Medoc TSA-II Neurosensory Analyser, a computer-controlled device capable of generating highly repeatable thermal stimuli and recording the time of the response given from the volunteers. Measurements were performed before capsaicin administration and then after its removal for the following 30 minutes (at 5 minute-interval). Secondary measurements included intensity of the flare reaction of the skin, self perceived reporting of pain intensity and extension of the allodinia area by using the Von Frey Hair Test.

Computerised Tests (attention and memory)

• Simple Reaction Time test (e-prime module)
• Sternberg Memory test (e-prime module)
• Digit Span Test (e-prime module)
• Stroop Test (e-prime module)

Tracking-Attention

• Wechsler Adult Intelligence Scale-Revised
  • Digit Symbol Substitution Test (DSST)
• The ‘Deux Barrages’ Test (DBT)

Mood

• Positive and Negative Affect Schedule (PANAS)
• The Profile of Mood States (POMS)
• The Bond & Lader Visual Analogue Scale of Mood and Alertness (BLVAS)

Memory

• The Hopkins Verbal Learning Test - Revised (HVLT-R)
• Working Memory: (Sequential Number Recall Task)

Sleep

• The Pittsburgh Sleep Questionnaire (PSQI)
• The Leeds Sleep Evaluation Questionnaire (LSEQ)
• The Stanford Sleepiness Scale (SSS)

Smoking Dependence

• The Fagerström Tolerance Questionnaire
• Shiffman Smoking Questionnaire *
• Schneider Smoking Questionnaire *
• Questionnaire on Smoking Urge - Brief Form

Recently we performed an experimental clinical trial with alprazolam using fMRI in resting state as a radiological tool.  The aim of the study was to highlight the presence of modifications in the Default Mode Network (DMN) detected by means of fMRI in Resting State after the administration of a neurotropic drug, the Alprazolam, and therefore to suggest fMRI as an alternative and non invasive tool for future pharmacological experimentations in vivo. The reproducibility of fMRI in Resting State was demonstrated with a consistent detection of DMN in all subjects and all conditions, furthermore a statistically non-significant difference between baselines was found. The Dual-Regression analysis showed a diffuse significant higher functional connectivity in the brain after the administration of Alprazolam, mainly in the precuneus/posterior cingulate cortex within the DMN, and also between the DMN and other cerebral areas, in particular the basal ganglia. No significant differences in DMN were detected after placebo administration. Hence, fMRI should be considered an applicable model in humans with new drug in early phase clinical trials.