People generalize too much.
There are many kinds of scepticism. Almost none of them translate into actual fears or doubts that the lived experiences of the sceptic are somehow not to be trusted. Sceptic philosophers generally do not suffer from schizophrenia or some kind of pathological fears or delusions.
There is a variant of radical scepticism, called Pyrrhonistic scepsis, or Pyrrhonism, going back to Pyrrho of Elis (3d century BCE) and developed in the books of Sextus Empiricus, that is generally totally misunderstood, misrepresented, and overly simplified, even by certain famous modern philosophers. This form of scepsis does have practical relevance and is related to lived experience. It presents itself as a biographical narrative - taking extraordinary care not to make any knowledge claims - where the sceptic reports that while searching for truth, they just were not able to find any convincing arguments for or against any of the knowledge claims that other philosophers tend to make. But yet, while keeping an open mind about any of those issues, they also found the peace of mind that they'd originally hoped to find. Originally they thought that this peace of mind could only be found by discovering some truth they could really believe in, but it turned out (it so happened for them) that by giving up, by keeping an open mind, rather than adhering to some dogma, they found that peace of mind. -- Scepsis here does translate into a way of life (though not a "view" or "philosophical theory" or something like that) and goes hand in hand -- not with doubting everything but with keeping an open mind. Scepsis doesn't mean doubt - but inquiry, staying curious, not stopping with questioning.
When a sceptic then presents sceptical "arguments", those arguments are really challenges to anyone who does have positive opinions, to anyone who does believe they really know this or that. For instance the following argument, from Sextus book Against the Logicians - I've never seen a convincing argument against it:
Those who claim for themselves to judge the truth are bound to possess a criterion of truth. This criterion, then, either is without a judge's approval or has been approved. But if it is without approval, whence comes it that it is trustworthy? For no matter of dispute is to be trusted without judging. And, if it has been approved, that which approves it, in turn, either has been approved or has not been approved, and so on ad infinitum.
Sceptics are usually well aware that a claim like "There is no truth" is self-contradictory. So, they do not make claims like that.
A non-biased, excellent overview and explanation of this form of scepsis - both as way of life and in regards to it's possible importance - can be found in Arne Naes' study Scepticism
In the Chinese classical tradition, in particular in Zhuang-zi, we find a sceptic who is just as radical as Sextus -- and who has a similar level of logical finesse -- but whose sceptical attitude seems to have been more inspired by a basic indeterminancy of language. For instance, consider this passage:
Now, saying is not blowing breath. Saying has something to say. Only, what it says is never fixed. Have we then actually said something? Or have we perhaps never said something? If you consider it different from the twittering of baby birds, is there actually a distinction, or is there no distinction? How is the Way hidden that we have "genuine" and "false"? How does saying conceal so that we have a "right" and a "wrong", "it's the case" versus "it's not the case"? The Way is hidden by shallow accomplishments. Saying hides by it's flourishes and verbiage.
Language has often been seen as something that is uniquely human - but is it so, really? Recently there have been some exciting breakthroughs in decoding the click language of sperm whales
So, I'm tempted to take Zhuang-zi's question about the baby birds literally :)