I agree methamphetamine (especially higher doses) can often result in a sweaty, trembling mess of neurotoxic punishment. I think a lot of the paranoia from the residual stimulation/psychosis effects from the m-amp can be translated into a sense of heavy guilt. The prosexual properties often lead to prolonged sessions of porn and masturbation, which for some individuals can induce strong feelings of guilt and shame. After long runs of being twacked the fuck out, I always feel like everyone around me could tell right away (not unlike schizophrenia and the paranoia which entails. I was on methamphetamine specifically (or coming down from) towards the end of the run when it certainly just becomes insane and dysphoric. The dopaminergic fuckery is painfully obvious.
I also found that neuroprotective supplements/vitamins post-loaded before dosing makes a huge difference on the quality of the actual high, preventing neurotoxicity (i.e. melatonin, ashwaghanda, chelated magnesium, L-tyrosine, fish oil) and other substances (i.e. clonazepam, cannabis, and nicotine- MOA-ihibition from the harmala alkaloids in tobacco)