Investigating Mental Health of US College Students During the COVID-19 Pandemic: Cross-Sectional Survey Study.

BACKGROUND: Evidence suggests that the COVID-19 pandemic has generally increased levels of stress and depression among the public. However, the impact on college students in the United States has not been well-documented. OBJECTIVE: This paper surveys the mental health status and severity of depression and anxiety of college students in a large university system in the United States during the COVID-19 pandemic. METHODS: An online survey was conducted among undergraduate and graduate students recruited from Texas A&M University via email. The survey consisted of two standardized scales-the Patient Health Questionnaire-9 and the General Anxiety Disorder-7-for depression and anxiety, and additional multiple-choice and open-ended questions regarding stressors and coping mechanisms specific to COVID-19. RESULTS: Among the 2031 participants, 48.14% (n=960) showed a moderate-to-severe level of depression, 38.48% (n=775) showed a moderate-to-severe level of anxiety, and 18.04% (n=366) had suicidal thoughts. A majority of participants (n=1443, 71.26%) indicated that their stress/anxiety levels had increased during the pandemic. Less than half of the participants (n=882, 43.25%) indicated that they were able to cope adequately with the stress related to the current situation. CONCLUSIONS: The proportion of respondents showing depression, anxiety, and/or suicidal thoughts is alarming. Respondents reported academic-, health-, and lifestyle-related concerns caused by the pandemic. Given the unexpected length and severity of the outbreak, these concerns need to be further understood and addressed.

Porocytosis: a transient pore array secretes the neurotransmitter packet.

The porocytosis hypothesis is based on the arrayed nature of synaptic vesicles which forms the anatomical functional unit of secretion. The presynaptic array and the postsynaptic array of receptors form a synaptomere which is the unit of transmission. A transient increase in calcium ions, triggered by an action potential, activates all pores of the array to pulse transmitter. The array insures transmission while permitting a frequency dependent amount of secretion. Therefore the amount of secretion is variable which permits plasticity. Secretion from the array has the property of immediate synaptic plasticity whereas a change in array size would change synaptic strength. The robust nature of the array insures fidelity of transmission, a frequency dependent dynamic signature of transmission giving the property of immediate plasticity; and, a change in array size yields a change in synaptic strength for long term reliability.

The synaptic bouton acts like a salt shaker.

The physiological quantal responses at the neuromuscular junction and the bouton-neuron show two classes based on amplitude such that the larger class is about 10 times that of the smaller class; and, the larger class is composed of the smaller class. The ratio of the two classes changes with synaptogenesis, degeneration, nerve stimulation, and is readily altered with various challenges (ionic, tonicity, pharmacological agents). Statistical analyses demonstrate that each bouton or release site at the neruomuscular junction (NMJ) secretes a standard amount of transmitter (one quantum) with each action potential. The amount of transmitter secreted (quantal size) is frequency dependent. The quantal-vesicular-exocytotic (QVE) hypothesis posits that the packet of secreted transmitter is released from one vesicle by exocytosis. The QVE hypothesis neither explains two quantal classes and subunits nor exocytosis of only one vesicle at each site. The latter observation requires a mechanism to select one vesicle from each array. Our porocytosis hypothesis states that the quantal packet is pulsed from an array of secretory pores. A salt shaker delivers a standard pinch of salt with each shake because salt flows through all openings in the cap. The variation in the pinch of salt or transmitter decreases with an increase in array size. The docked vesicles, paravesicular matrix, and porosomes (pores) of a release site form the secretory unit. In analogy with the sacromere as the functional unit of skeletal muscle, we term the array of docked vesicles and paravesicular grid along with the array of postsynaptic receptors a synaptomere. Pulsed secretion from an array explains the substructure of the postsynaptic response (quantum). The array guarantees a constant amount of secretion with each action potential and permits a given synapse to function in different responses because different frequencies would secrete signature amounts of transmitter. Our porocytosis hypothesis readily explains a change in quantal size during learning and memory with an increase in the number of elements (docked vesicles) composing the array.

Porocytosis: secretion from small and medium-diameter vesicles and vesicle arrays without membrane fusion.

We have recently proposed a mechanism to describe secretion, a fundament process in all cells. That hypothesis, called porocytosis, embodies all available data, and encompasses both forms of secretion, i.e., vesicular and constitutive. The current accepted view of exocytotic secretion involves the physical fusion of vesicle- and plasma membranes. However, that hypothesized mechanism does not fit all available physiological data (Silver et al., 2001; Kriebel et al., 2001). Energetics of apposed lipid bilayers do not favor unfacilitated fusion. Calcium ion levels are elevated in microdomains at levels of 10(-4)-10(-3)M for 1 ms or less, with the calcium ions showing limited lateral mobility at the site of secretion (Llinas et al., 1992, Silver et al., 1994). We consider that calcium ions, whose mobility is restricted in space and time, establish "salt-bridges" among adjacent lipid molecules, and establishes transient pores that span the vesicle and plasma membrane lipid bilayers; the lifetime of that transient pore being completely dependent on duration of sufficient calcium ion levels.