                             In the

    United States Court of Appeals
                For the Seventh Circuit
                   ____________________

No. 17-1938
CORDELL SANDERS,
                                              Plaintiff-Appellant,
                               v.

MICHAEL MELVIN, et al.,
                                           Defendants-Appellees.
                   ____________________

           Appeal from the United States District Court
                 for the Central District of Illinois.
          No. 16-cv-1366-JBM — Joe Billy McDade, Judge.
                   ____________________

   ARGUED OCTOBER 4, 2017 — DECIDED OCTOBER 17, 2017
               ____________________

   Before BAUER, EASTERBROOK, and MANION, Circuit Judges.
    EASTERBROOK, Circuit Judge. Cordell Sanders has been in
solitary confinement at Pontiac Correctional Center for eight
years, and the prison plans to keep him there for another ten.
He has been diagnosed with intermittent explosive disorder,
schizoaffective disorder, and other conditions that make him
dangerous to others when allowed greater liberty. But Sand-
ers alleges in this suit under 42 U.S.C. §1983 that, although
his confinement may protect guards and other prisoners, the
2                                                            No. 17-1938

isolation, heat, and restricted air flow in solitary confinement
harm him by aggravating both his psychological problems
and his asthma. He contends that the conditions of his con-
finement—if not the fact of long-term solitary confinement
under any conditions—violate the Constitution.
    The filing fee for initiating litigation in federal court is
$400. Contending that he does not have this much money,
Sanders asked for permission to litigate in forma pauperis, a
status that for a prisoner means payment over time rather
than in advance. See 28 U.S.C. §1915(b). But there is an ex-
ception:
    In no event shall a prisoner bring a civil action or appeal a judg-
    ment in a civil action or proceeding under this section if the pris-
    oner has, on 3 or more prior occasions, while incarcerated or de-
    tained in any facility, brought an action or appeal in a court of
    the United States that was dismissed on the grounds that it is
    frivolous, malicious, or fails to state a claim upon which relief
    may be granted, unless the prisoner is under imminent danger of
    serious physical injury.

28 U.S.C. §1915(g). Judges refer to this as the three-strikes
rule. See Bruce v. Samuels, 136 S. Ct. 627 (2016). Sanders con-
cedes that at least three of his prior suits or appeals have
been dismissed as frivolous, malicious, or failing to state a
claim. The district court held that he therefore must pay $400
to pursue the current suit. 2017 U.S. Dist. LEXIS 41026 (C.D.
Ill. Mar. 22, 2017). He did not pay, the suit was dismissed,
and he appeals from that final decision.
    Sanders maintains that asthma and a deteriorating men-
tal state satisfy the exception to the exception: a “prisoner …
under imminent danger of serious physical injury” may liti-
gate in forma pauperis no matter how many strikes he has.
Mental deterioration, however, is a psychological rather than
No. 17-1938                                                   3

a physical problem. Physical problems can cause psycholog-
ical ones, and the reverse, but the statute supposes that it is
possible to distinguish them. A claim of long-term psycho-
logical deterioration is on the psychological side of the line.
Prisoners facing long-term psychological problems can save
up during that long term and pay the filing fee.
    Sanders’s contention that heat and restricted ventilation
aggravate his asthma alleges a risk of physical injury, but not
an “imminent” one—and a “struggle to breathe”, which
Sanders alleges, is a normal incident of asthma rather than a
“serious” incremental harm. Many risks, for many people
(including asthmatics), never come to pass or turn out not to
be serious; Sanders has not offered any reason to think that
serious physical injury from asthma is “imminent”. If fears
about the future made for an “imminent danger of serious
physical injury”, the statute would not serve to curtail litiga-
tion by those who have demonstrated a propensity to make
baseless or malicious claims. Observations about the general
dangers of prison life therefore do not suffice. Cf. Gevas v.
McLaughlin, 798 F.3d 475, 480–81 (7th Cir. 2015).
   But Sanders advances a stronger contention: that his
mental condition (the prison itself classifies Sanders as “seri-
ously mentally ill”) disposes him to self-harm. He asserts
that he has twice tried to commit suicide and at least once
engaged in self-mutilation. According to his complaint, the
mental-health staff at Pontiac ignores the problems of in-
mates in solitary confinement unless they engage in self-
harm. Cutting off an ear or other self-mutilation is a form of
physical injury; that the would-be plaintiff inflicts the injury
himself, and does so because of mental problems, does not
make the harm less “physical” or less “serious.” See Rasho v.
4                                                    No. 17-1938

Elyea, 856 F.3d 469, 477–78 (7th Cir. 2017). That Sanders has
attempted self-harm multiple times lends support to his al-
legation that a future attempt is “imminent” unless he is re-
leased from solitary or allowed mental-health care. Courts
don’t accept allegations of danger uncritically. Taylor v. Wat-
kins, 623 F.3d 483, 485 (7th Cir. 2010); Ciarpaglini v. Saini, 352
F.3d 328, 330–31 (7th Cir. 2003). But Sanders’s history, cou-
pled with the prison’s diagnosis of his condition, makes his
allegations plausible. And plausibility is enough in a plead-
ing. Bell Atlantic Corp. v. Twombly, 550 U.S. 544 (2007).
     Nonetheless, the district court dismissed the allegations
out of hand, stating they are “self-serving.” Which they are.
Everything a litigant says in support of a claim is self-serving,
whether the statement comes in a complaint, an affidavit, a
deposition, or a trial. Yet self-serving statements are not nec-
essarily false; they may be put to the test before being ac-
cepted, but they cannot be ignored. Our opinion in Hill v.
Tangherlini, 724 F.3d 965 (7th Cir. 2013), recounts the circuit’s
flirtation with a doctrine that allows judges to disregard self-
serving statements, and it overrules any precedents that so
much as hinted in that direction. It is dismaying to see plau-
sible allegations labeled “self-serving” and then swept aside
after Hill and its predecessors such as Payne v. Pauley, 337
F.3d 767 (7th Cir. 2003).
    Having called Sanders’s allegations self-serving, the dis-
trict court added that they amount to a threat to engage in
volitional harm. How much control over his actions a men-
tally ill person such as Sanders possesses may be a difficult
medical, philosophical, or religious question that is not suit-
ed to summary resolution, but we assume for current pur-
No. 17-1938                                                  5

poses that he exercises at least some. That assumption does
not support the district court’s decision, however.
   The court assumed that volitional harm cannot be “im-
minent danger of serious physical injury.” Suppose a pris-
oner who has three or more strikes files a new suit protest-
ing the absence of a tennis court and adds: “If you do not al-
low me to proceed in forma pauperis, I will prick my finger
the very day you issue your decision; and as that would be
imminent physical injury, you must allow me to proceed
without prepaying the $400 fee.” Permitting such an attempt
at manipulation would effectively blot §1915(g) out of the
United States Code.
   But it does not follow that no volitional conduct satisfies
the statute. Suppose a prisoner alleges that a guard has
placed one of his fingers in a vise and turned the handle,
causing him anguishing pain but no physical harm. A state-
ment along the lines of “if this goes on for another week, I
will cut off the finger as the only way to get relief” would
identify imminent physical harm. The threat of self-
mutilation would not be a ploy to avoid an unwelcome stat-
utory rule. It would be a means of mitigating damages.
    When the prospect of self-harm is a consequence of the
condition that prompted the suit, a court should treat the al-
legation (if true) as imminent physical injury. And this is the
kind of allegation Sanders has advanced. He contends that
solitary confinement not only is injurious by itself but also
causes prisoners to lose the benefit of mental-health care,
and that only self-mutilation (or a credible threat of self-
mutilation) restores that care. That Sanders makes a choice
in this process does not negate the possibility that the com-
plained-of conduct forced this choice on him as the lesser
6                                                   No. 17-1938

evil. Note what we are not saying. We do not conclude that
all threats of self-harm by mentally ill prisoners permit them
to proceed in forma pauperis. Our conclusion, rather, is that
the potential self-harm that Sanders alleges may well be
caused by the complained-of conduct.
    Having found that Sanders has made a plausible allega-
tion of imminent, serious physical harm, we must remand
for further proceedings to determine whether the allegation
is true. The court cannot disregard the allegation as self-
serving, but neither must the court accept whatever a pris-
oner says. See, e.g., Fletcher v. Menard Correctional Center, 623
F.3d 1171, 1172–73 (7th Cir. 2010); Taylor, 623 F.3d at 485–86.
    A complaint’s allegations are just that: allegations. To
avoid the three-strikes rule of §1915(g), the complaint must
allege imminent, serious physical harm. This Sanders has
done. But if a claim is challenged by the defense, or seems
fishy to the judge, it must be supported by facts presented in
affidavits or, if appropriate, hearings. This is how allegations
of jurisdiction are handled. A plaintiff who alleges injury
caused by the defendant’s conduct—an allegation essential
to standing—must provide proof if challenged by the de-
fendant or the judge. See, e.g., Lujan v. Defenders of Wildlife,
504 U.S. 555, 559–62 (1992). Similarly, in litigation filed un-
der the diversity jurisdiction of 28 U.S.C. §1332, a plaintiff’s
allegations about the parties’ citizenship are accepted unless
they are challenged or seem collusive, and then they must be
proved. Determining the validity of allegations that a pris-
oner makes in an effort to avoid the three-strikes clause
should proceed similarly.
   If Sanders’s allegations of imminent physical harm are
untrue, then he must pay the whole filing fee promptly. Tay-
No. 17-1938                                                   7

lor, 623 F.3d at 486. See also Newlin v. Helman, 123 F.3d 429
(7th Cir. 1997) (describing means to collect fees owed by
prisoners who have struck out yet continue filing suits). And
if it turns out that Sanders has lied in an effort to manipulate
the judge, the case may be dismissed with prejudice as a
sanction even if he comes up with the $400. See, e.g., Thomas
v. General Motors Acceptance Corp., 288 F.3d 305, 306–07 (7th
Cir. 2002); Ammons v. Gerlinger, 547 F.3d 724, 725–26 (7th Cir.
2008).
     Sanders has not yet been directed to substantiate his alle-
gations. Once the defendants have been served with process
and responded to the complaint, the district court should
decide whether proof is necessary and, if it is, conduct ap-
propriate evidentiary proceedings. Rule 12(b) of the Federal
Rules of Civil Procedure was adopted before the enactment
of §1915(g) in 1996, and neither that Rule nor any other spec-
ifies a procedure for resolving disputes about the require-
ments of §1915(g)—or, indeed, any other issue relevant to
litigating in forma pauperis, such as a dispute about the plain-
tiff’s available assets. Until the Civil Rules make specific
provision for this issue, questions should be handled the
same way judges resolve disputes about jurisdiction or ven-
ue, with hearings and findings of fact under Rule 12(b)(1),
Rule 12(b)(2), and Rule 12(b)(3).
   The judgment is vacated, and the case is remanded for
proceedings consistent with this opinion.
