Question For Fellow Shrinks

Do you ever feel that there is just no hope of truly knowing whether a given person has a mental illness—let alone what the illness is? I mean, with all the possible confounding factors inherent in the history of any adult who has had even a moderately tough life— and with the fragility of the human brain (have you ever looked at this organ, out of a skull? It’s as sturdy as slightly overcooked oatmeal)-- how can you ever winnow out a diagnosis?

Example (purely fictitious, but hardly unusual in my practice): A 32 year old man presents with a wide variety of mental symptoms. Doesn’t even matter what they are—just assume they are many and varied—a mixture of mood, thought, cognitive, behavioral, and personality features.

You are lucky enough to get the following (unusually detailed) history: His mother was a smoker and drank heavily. He says “I almost died when I was being born.” He remembers his father beating his mother, but doesn’t know if his father ever beat him— he can’t recall anything before about age 6. The family lived in a run-down neighborhood and he had little supervision. When he was 9 he had an accident of some sort. He thinks he was unconscious for a time. He doesn’t remember the accident. His parents told him he fell off a deck. He also fell off a moped at some point and hit his head, without a helmet. In high school he drank heavily and used marijuana daily. He had few friends, but he hung out with a group who huffed inhalants (he says he “never tried it.”) He enjoyed asphyxiating himself for erotic arousal. His grades were always poor and he was frequently disciplined for bullying smaller children. He dropped out before graduation. He worked in a string of blue collar jobs including a smelting plant, an industrial cleaning service, and a cannery. He was arrested for possession of crack (which he says he was “holding” for a friend), as well as assault vs. the arresting officer. He was imprisoned for 9 months. He reports being raped in prison. He had a girlfriend but she took out a restraining order after accusing him of killing her ferret with a shotgun (which he denies). He says he has never been able to concentrate on anything, but felt this improved when he snorted cocaine (which he states he did only once.) He feels “jumpy” all the time.

The diagnos(es) is/are:

(a) Fetal alcohol syndrome
(b) PTSD from physical abuse from his parents
(c) PTSD from an accident
(d) PTSD from rape
(e) ADHD, lifelong, untreated
(f) Antisocial personality disorder
(g) Mild mental retardation, congenital.
(h) Mental disorder due to traumatic brain injury (“fall”)
(i) Mental disorder due to traumatic brain injury (moped accident)
(j) Mental disorder due to acute cerebral anoxia (at birth)
(k) Mental disorder due to repeated cerebral anoxia (autoasphyxiation)
(l) Mental disorder due to substances (childhood lead poisoning)
(m) Mental disorder due to substances (chronic alcoholism)
(n) Mental disorder due to substances (marijuana, crack, coke, PCP, heroin, LSD, mushrooms, god knows what.)
(o) Mental disorder due to substances (hydrocarbon inhalants)
(p) Mental disorder due to substances (heavy metals or other industrial toxins)
(q) Bipolar Disorder of any flavor
(r) Psychotic Disorder of any flavor
(s) Anxiety Disorder, of any flavor

Without some kind of time-machine, or magic CSI brain pathology decoder lab, it seems simply impossible to sort this out. So frustrating.