• Brain (cortex–occiput). Headache from mental exertion, especially occipital/vertex, with fullness and heaviness, better rest and cooling, worse continued study [Allen], [Clarke].
• Spine (cervico-lumbar). Burning or hot aching along spine, lassitude, weak knees, cannot stand long; correlates with neurasthenic state [Boger], [Boericke].
• Male generative. Sexual debility, nocturnal emissions with great exhaustion, erections feeble; mental overwork and heat typical aetiologies [Hering], [Clarke].
• Urinary tract. Irritable bladder, frequent urging, dribbling after urination; weakness of neck of bladder mirrors spinal atony [Allen], [Clarke].
• Lower limbs. Heaviness, numb–tired legs, giving way at knees after study or heat; “lead-like” fatigue [Boger], [Clarke].
• Eyes (functional strain). Brow–eye fatigue after reading; lids heavy; ache tracks with head symptoms [Allen], [Clarke].
• Heart–vagus (effort-intolerance). Palpitation and faintness on slight exertion during exhausted states; relieved by rest [Boericke], [Nash].
• General trophic field. Prostration, worse summer heat/sun, mental labour, sexual excess; better rest, cooling, quiet [Clarke], [Boericke].

• Rest; cessation of study/work — core improvement of headache, back, sexual weakness [Allen], [Clarke].
• Cool air/cooling applications — soothes burning spine and throbbing occiput; confirms heat polarity [Clarke], [Boericke].
• Lying down; reclining with head supported — eases occipital pressure and lumbar weakness [Boger], [Allen].
• Gentle motion after brief rest — steadies heavy legs without taxing reserves [Clarke].
• Quiet; mental disengagement — reduces brain-fag and palpitant unrest [Nash], [Clarke].
• Cold bathing (some) — braces spine and genitals temporarily [Boericke], [Clarke].
• Early sleep — restores for a time; a practical management cue [Tyler].
• Pressure to occiput/neck — mitigates pressing pain while resting [Allen].

• Mental exertion; protracted study — precipitates occipital headache, spinal burn, sexual drain [Allen], [Clarke].
• Heat of summer; sun; warm rooms — heightens prostration, headache, palpitation [Clarke], [Boericke].
• Sexual excess; frequent emissions — deepens lassitude, backache, mental dulness [Hering], [Clarke].
• Standing long; ascending — knees give way, lumbar ache [Boger].
• Afternoon to evening — brain-fag mounts with day’s load [Clarke].
• Alcohol/coffee (some) — overstimulates, then worse exhaustion [Allen], [Nash].
• Crowded, hot rooms — head throbs, faintness [Clarke].
• Attempting coition — failure with exhaustion and backache after [Hering], [Clarke].

The mental state is that of overworked exhaustion: ideas come slowly, are hard to hold, and application quickly induces occipital pressure with a feeling of spinal heat rising to the head—an exact echo of the worse for mental exertion and worse heat modalities already recorded [Allen], [Clarke]. A student who endures long sessions reports dulness, sleepiness, and a wish to lie down, yet sleep is not deeply refreshing when the spinal burning persists; relief comes with cool air and quiet, reiterating the listed ameliorations [Clarke], [Tyler]. Unlike Nux-v., there is no irritable combativeness; unlike Gelsemium, there is not heavy drowsy stupefaction but rather spent clarity—the mind knows the task but the nervous battery is flat [Kent], [Nash]. Anxiety is secondary and practical (“I cannot finish”), increasing toward evening with palpitation on slight effort, then subsiding in rest, which aligns with Heart and Generalities [Boericke], [Clarke]. The will falters around sexual weakness, with discouragement after failures or nocturnal emissions; this feeds back into study-avoidance, establishing the classic Pic-ac. triad—brain-fag, spinal burn, sexual atony [Hering], [Clarke]. Heat in summer induces nervous apathy and head aversion to effort; the same subject works tolerably in the cool months, a seasonal polarity integral to this remedy [Clarke], [Boericke]. [Proving] [Clinical]

Headache is occipital–vertex, pressing/heavy, often with heat or burning line from nape upward after study; reclining, cool air, and pressure to the occiput relieve, while warm rooms, sun, and continued mental work renew the pain, reproducing modalities precisely [Allen], [Clarke]. The scalp may feel tight, and eyes grow tired with brow ache, linking Head and Eyes [Allen]. Morning can be fair, but afternoon/evening brings a dull, congestive weight that enforces rest; a short nap restores for a time, then the cycle repeats with any attempt at application, mirroring the economy of the remedy [Clarke], [Tyler]. Unlike Phos-ac., the pain is less “white-apathic” and more heated, congestive, spinal-linked; unlike Cocculus, there is no night-watching nausea as the prime driver; unlike Kali-phos., burning spine and heat-worse are distinctive [Kent], [Boger]. [Proving] [Clinical]

Ocular fatigue coincides with brow pressure; print blurs after a short effort; lids feel heavy, and aching tracks to the occiput; rest, darkness, and cool air assist, matching Better-for-rest/cooling [Allen], [Clarke]. There is little photophobia; the issue is effort-intolerance. In the overworked, conjunctival injection may accompany the headache; cold sponging relieves. Compare Ruta (eye strain with scleral soreness) and Physostigma (true ciliary spasm with vagal sinking); Pic-ac. is the over-heated student with occipital pressure and spinal burn [Kent], [Clarke]. [Clinical]

Fullness and ringing during congestive headaches; noise and close rooms intensify head symptoms, so quiet, cool surroundings are preferred—again affirming the environmental modalities [Clarke]. Sharp neuralgias are not typical; if present, look to Spigelia. [Clinical]

Congestive stuffiness with a hot head during study or in warm rooms; open air clears; coryza is not central unless heat or fatigue is extreme [Clarke]. [Clinical]

Face grows flushed with head heat, then pale and tired after emissions or overwork; cool applications to nape/occiput ease the expression and pain, cross-linking to Head [Clarke]. [Clinical]

Dryness of mouth with long study; tongue feels hot; desires cool water in heat; speech is slow when the occipital pressure mounts, and the patient answers briefly to conserve energy [Allen], [Clarke]. [Clinical]

Not a primary sphere; tooth pressure may appear in hot rooms with head congestion, easing in cool air. In dental fatigue after overwork, compare Nux-v. [Clinical]

Dry, hot throat in warm rooms; cool sips relieve; voice tires quickly if speaking while head is heavy; quiet suits the remedy [Clarke]. [Clinical]

Loss of appetite with head-congestion after study; nausea if effort is forced; better rest, cooling, and light food; alcohol/coffee give a brief lift followed by worse prostration, reflecting the worse stimulants note [Allen], [Clarke], [Nash]. [Clinical]

Atony with dragging fatigue; in heat, bowels may become sluggish with flatulence from inactivity; better cool air and gentle walking; if cramping predominates think Cocculus/Coloc. rather than Pic-ac. [Clarke], [Boger]. [Clinical]

Frequent urging, scanty flow, dribbling after urination, and a sense of neck-of-bladder weakness, especially after mental strain or emissions; cooling and rest lessen irritability, cross-linking to Affinity (urinary) [Allen], [Clarke]. [Clinical]

Constipated from fatigue or ineffectual urging in the exhausted; backache accompanies efforts; improvement follows rest and cooling; explosive diarrhoea is foreign to the centre (contrast Phos-ac.) [Clarke], [Allen]. [Clinical]

Nocturnal emissions with great prostration, erections feeble, desire reduced; attempt at coition often fails, followed by lumbar aching and occipital pressure; heat and overwork aggravate; cool bathing or a day of rest improves—a classic sphere for Pic-ac. [Hering], [Clarke], [Boericke]. Differentiate from Selenium (lascivious thoughts with weakness), Staphisagria (moral mortification), and Phos-ac. (painless drains with apathy rather than heated congestion) [Kent], [Clarke]. [Clinical]

Less characteristic, yet neurasthenic fatigue about menses with occipital headache and spinal heat suggests the remedy, especially in summer; sexual atony and palpitant effort-intolerance mirror the general state; rest/cooling are again decisive [Clarke], [Tyler]. [Clinical]

Short breath on exertion in warm rooms; better cool air; sighing when overdone; the breathing mirrors the energy economy and heat polarity [Clarke]. [Clinical]

Palpitation with faintness on ascending or after mental strain; pulse may be soft; quiet recumbency restores, matching Better-for-rest [Nash], [Clarke]. Not a structural heart remedy—functional fatigue dominates. [Clinical]

Oppression with palpitation on slight exertion during exhausted phases; warm rooms aggravate, cool air and rest ease; no primary bronchitic picture (contrast Gelsemium/Phosphorus); the chest shares the effort-intolerance theme [Boericke], [Clarke]. [Clinical]

Cardinal sphere with burning along the spine, lumbar weakness, knees give way; standing or prolonged sitting at work aggravates; lying, cooling, and pressure ameliorate, restating multiple modalities [Boger], [Boericke], [Clarke]. The nape-to-occiput tract transmits the head pain after study, making back care central to management. [Proving] [Clinical]

Heaviness and tired numbness of legs, particularly thighs/knees, after mental labour or heat; giving way on stairs; hands tremble slightly under pressure of work; improves with rest, cool air, and a brief nap, paralleling Generalities [Boger], [Clarke]. [Clinical]

In toxic states, yellow staining is known; clinically, sweaty, easily heated skin in summer, desire for cooling; eruptions are not a keynote for prescribing (contrast Sulphur) [Hughes], [Clarke]. [Toxicology] [Clinical]

Sleepiness from study; falls asleep early, wakes heavy if spinal burning persisted; short sleep may restore enough to finish a light task, but overuse quickly re-provokes occipital pressure and palpitation—the classic expend-and-crash cycle [Clarke], [Tyler]. Dreams of work undone reflect the same economy of weakness. Cooling the room improves quality. [Clinical]

Work-dreams, pressure to perform, climbing with weak legs, or sexual dreams followed by lassitude; awakening finds occipital weight unless cool and quiet have been secured—again cross-linking modalities [Clarke]. [Clinical]

Not a high-fever remedy; flushes of heat during study or in warm rooms, with sweat and faintness, all settling in cool air and repose. If adynamic fever with painless diarrhoea arises, think Phos-ac. instead [Clarke], [Boericke]. [Clinical]

Heat predominates: hot head, burning spine, summer aggravation; sweat follows slight effort; chill from exhaustion when overdone in hot weather; cooling corrects—clear polarity [Clarke], [Boericke]. [Clinical]

Desires cool water; alcohol/coffee may stimulate then collapse; light diet suits during recovery; overeating in heat worsens head and spine complaints [Allen], [Nash], [Clarke]. [Clinical]

Pic-ac. personifies cerebro-spinal exhaustion with occipital headaches from mental exertion, burning spine, lumbar weakness with giving-way knees, sexual atony with emissions, urinary dribbling, and effort-intolerance, all worse from study, heat of summer/sun, standing/ascending, sexual excess, hot rooms, and stimulants, and better from rest, cool air, lying, pressure to occiput, quiet, and sometimes cold bathing [Allen], [Hering], [Clarke], [Boger], [Boericke]. Differentiate from Phos-ac. (white, drained, painless diarrhoea, desire for cold drinks, short-sleep clarity), Kali-phos. (nerve prostration with anxiety/startle), Gelsemium (drowsy heaviness, drooping lids), Cocculus (night-watching, vertigo, nausea), Selenium (lascivious thoughts with weakness), and Nux-v. (irritable overwork) by the occipito-spinal burning, summer-heat aggravation, leg heaviness/giving way, and sexual atony of Pic-ac. [Kent], [Nash], [Clarke], [Boger]. [Proving] [Clinical]

Aetiology: mental overwork / study

• Kali-phos. — Nerve anxiety, startles, insomnia; Pic-ac.: burning spine, occipital pressure, heat-worse [Kent], [Clarke].
• Phos-ac. — Apathy, painless diarrhoea, cold-water desire; Pic-ac.: heated congestion, no diarrhoea, summer worse [Clarke], [Nash].
• Nux-v. — Irritable, spasmodic; Pic-ac.: quiet collapse, leg heaviness, sexual atony [Kent].

Headache from exertion

• Gelsemium — Drowsy, drooping lids, occipital ache; Pic-ac.: spinal burn, heat-worse, rest/cool better [Clarke].
• Cocculus — Night-watching, nausea/vertigo; Pic-ac.: no primary night-watch aetiology, more heat-congestive [Nash].
• Ruta — Eye-strain scleral/tenon soreness; Pic-ac.: occipital–spinal axis [Kent].

Sexual debility / emissions

• Selenium — Lascivious thoughts, oozing prostatic fluid; Pic-ac.: desire diminished, exhaustion marked [Clarke].
• Staphisagria — Mortification/anger causes sexual weakness; Pic-ac.: overwork/heat causation, spinal burn [Kent].
• Agnus-c. — Profound impotence, cold genitals; Pic-ac.: effort-linked head–spine features [Clarke].

Leg weakness / spinal atony

• Phosphorus — Burning, anxiety, emaciation; Pic-ac.: heaviness, giving way, heat-worse, less fear [Kent].
• Causticum — Paretoid weakness, contractures; Pic-ac.: fatigue weakness with occipital headache [Boger].

Urinary irritability

• Sabal/Pareira — Prostatic and colic features; Pic-ac.: post-exertion dribbling with spinal fatigue [Clarke].
• Gelsemium — Atonic bladder with drowsiness; Pic-ac.: heat-worse neurasthenia [Clarke].

• Complementary: Kali-phos. — After Pic-ac. lifts spino-cerebral burn, Kali-phos. consolidates nerve tone [Kent], [Clarke].
• Complementary: Phos-ac. — Where drain states remain without heat/congestion, to complete convalescence [Nash], [Clarke].
• Follows well: Nux-v. — When irritability from overwork has been calmed; Pic-ac. then restores spent battery [Kent].
• Follows well: Gelsemium. — After heavy drowsy occiput yields, residual spinal burn/sexual atony points to Pic-ac. [Clarke].
• Precedes well: Selenium. — If persistent sexual weakness with lascivious thoughts remains after Pic-ac. [Clarke].
• Compare: Cocculus, Ruta, Agnus-c., Caust., Phos. — select by modality (heat, exertion) and axis (head–spine vs eye strain vs fear) [Kent], [Boger], [Clarke].
• Antidotal tendencies (functional): Rest, cool air, mental abstinence, brief sleep—nursing that mirrors modalities and supports action [Clarke], [Tyler].

• Students/clerks with occipital headache, spinal burning, leg heaviness, sexual atony after overstudy/heat: Pic-ac. 6C–30C in short courses; enforce rest/cooling [Allen], [Clarke], [Boericke].
• Neurasthenia of summer (palpitation on slight effort, hot rooms intolerable): Pic-ac. 30C evening; ventilate and cool; alternate Kali-phos. later to consolidate [Clarke], [Kent].
• Emissions → prostration with lumbar ache and occipital pressure: single 200C then wait; counsel abstinence, cool bathing, early sleep [Hering], [Clarke].
• Workhead: if irritability dominates, begin Nux-v., then Pic-ac. to restore the battery [Kent], [Nash]. [Clinical]

Mind

• MIND – Prostration – mental exertion aggravates. Brain-fag keynote [Allen], [Clarke].
• MIND – Concentration difficult – from overwork. Exhaustive type [Allen].
• MIND – Anxiety – about work, evening. Effort-intolerance [Clarke].
• MIND – Aversion to mental labour – heat aggravates. Summer neurasthenia [Clarke].

Head

• HEAD – Pain – occiput/vertex – from mental exertion – heat aggravates – rest/cool air ameliorates. Central rubric [Allen], [Clarke].
• HEAD – Congestion – warm room aggravates. Environmental trigger [Clarke].
• HEAD – Pressure – nape to occiput. Spino-cranial axis [Boger].

Spine/Back

• BACK – Pain – burning – spine – heat aggravates – rest/cool ameliorates. Signature [Boger], [Boericke].
• BACK – Weakness – lumbar – standing aggravates – lying ameliorates. Giving way knees [Boger].

Male/Urinary

• MALE – Emissions – debilitating – erections feeble. Sexual atony [Hering], [Clarke].
• MALE – Impotence – from overwork/sexual excess. Aetiology-focused [Clarke].
• URINATION – Dribbling – after urination – weakness of bladder neck. Atony sign [Allen].
• URINE – Frequent urging – small quantities – mental exertion aggravates. Functional irritability [Clarke].

Extremities

• EXTREMITIES – Weakness – knees give way – on ascending. Functional collapse [Boger].
• EXTREMITIES – Heaviness – lower limbs – after mental exertion. Leg keynote [Clarke].

Generalities

• GENERALS – Exhaustion – from mental exertion. Master rubric [Allen], [Clarke].
• GENERALS – Heat – summer – aggravates. Seasonal polarity [Clarke], [Boericke].
• GENERALS – Rest ameliorates; exertion aggravates. Core polarity [Nash].
• GENERALS – Hot room aggravates; cool air ameliorates. Environment [Clarke].

Allen, T. F. — Encyclopaedia of Pure Materia Medica (1874–79): proving symptoms (head, spine, urinary), mental overwork, modalities.
Hering, C. — The Guiding Symptoms of our Materia Medica (1879): sexual atony, emissions with prostration, spinal weakness.
Hughes, R. — A Cyclopaedia of Drug Pathogenesy (1870): toxicology of picric acid; neuro-asthenic and spinal effects; heat aspects.
Clarke, J. H. — A Dictionary of Practical Materia Medica (1900): general picture; summer aggravation; urinary and sexual notes; relationships.
Boericke, W. — Pocket Manual of Homeopathic Materia Medica (1901): head–spine–sex triad; modalities; clinical hints.
Boger, C. M. — Synoptic Key of the Materia Medica (1915): spinal burning; leg giving way; modality synthesis and relations.
Kent, J. T. — Lectures on Homeopathic Materia Medica (1905): differentials (Nux-v., Gels., Kali-phos., Phos-ac., Selenium).
Nash, E. B. — Leaders in Homeopathic Therapeutics (1899): neurasthenia from overwork; stimulant aggravations; management contrasts.
Dewey, W. A. — Practical Homeopathic Therapeutics (1901): exhaustion states; rest/cooling regimen adjuncts.
Tyler, M. L. — Homoeopathic Drug Pictures (1942): “brain-fag” portraits; bedside management points for summer neurasthenia.
Phatak, S. R. — Materia Medica of Homoeopathic Medicines (1941): concise keynotes corroborating head–spine–sex sphere.